Le financement a été assuré par l&#39;Université de l&#39;Utah. Nous tenons à remercier le Dr J. Xu (UC Merced) et Dr. Reddy BJN (UC Irvine) pour des discussions utiles.

1. Installation de 980 nm de longueur d&#39;onde unique piège optique <ol><li> Piégeage optique à 980 nm longueur d&#39;onde est souvent optimal pour des expériences de biophysique et de diodes laser bon marché sont disponibles avec une puissance aussi élevée que 300 mW. Il est préférable pour une diode laser à queue de cochon à maintien de polarisation fibre monomode avec un diamètre de champ de mode connue. La fibre doit être suffisamment long pour agir comme un filtre de mode et est généralement terminée par un navigateur FC / PC ou un connecteur FC / APC. Parmi ceux-ci, FC / APC est préférable de minimiser la rétro-réflexion des instabilités de rétroaction de lumière et de potentiel. </li><li> Fixer la diode laser à 980 nm dans un support qui permet de puissance et de contrôle de la température. Il est préférable de fixer la monture sur une table optique directement à maximiser la dissipation thermique passive et minimiser ainsi le risque d&#39;échec de la diode en raison d&#39;un dysfonctionnement du régulateur de température. </li><li> Monter le connecteur de fibre PC / APC à des optiques de collimation du faisceau. Il estessentiel afin d&#39;assurer que le faisceau collimaté de manière encore divergence minimale ports fibre réglables sont plus utiles. Assurez-vous que le port de fibre choisie correspond au diamètre du champ de mode de la fibre amorce de diode. Si le faisceau doit être tramée en utilisant des déflecteurs acousto-optiques (AOD) ou par des déflecteurs électro-optiques (NEM), la taille du faisceau laser collimaté doit être légèrement inférieure à la dimension de l&#39;ouverture du déflecteur. </li><li> Fixer l&#39;adaptateur collimateur de la table optique à une distance suffisante du microscope pour permettre faisceau de routage, l&#39;expansion et le placement des autres composants souhaités. Réglez le port fibre pour assurer taille du faisceau cohérent sur des distances comparables à la trajectoire globale du faisceau du microscope. </li><li> Installer des miroirs indiqués sur la figure 1. Retirer l&#39;objectif du microscope et d&#39;utiliser des miroirs pour acheminer le faisceau à travers l&#39;ouverture dans l&#39;étage de montage objectif. Si l&#39;on préfère, le placement des miroirs dichroïques DM1 et DM3 peut être omis jusqu&#39;àplus tard. DM2 et DM3 sont à la fois Shortpass et transmettre la lumière visible, tout en reflétant le proche infrarouge et au-dessus. </li><li> Il est utile de monter temporairement un pointeur laser rouge à la place de l&#39;objectif, aligné sur l&#39;axe optique du microscope. Un adaptateur mécanique sur mesure est nécessaire pour assurer la concentration du pointeur laser. Faisceau visible à partir du pointeur laser peut alors être acheminé vers le centre de l&#39;ouverture du port de la fibre et peut ensuite être utilisé pour installer les lentilles (voir ci-dessous). </li><li> Installez le 980 nm élargisseur de faisceau (L8 et L9) à une distance convenable du port fibre pour permettre l&#39;insertion future des composants de la direction (AOD ou EOD) si nécessaire 1. Le faisceau élargi doit légèrement déborder l&#39;ouverture focal arrière de l&#39;objectif. (Ici, des focales de 125 mm et 60 mm sont dans un arrangement de Kepler à environ le double de la taille du faisceau). Utilisez faisceau du pointeur laser visible (voir section 1.6) pour assurer le placement de la lentille et l&#39;alignement approximatif. </li><li> Install les lentilles de direction de 980 nm (L2 et L3) dans un système de télescope comme indiqué (ici les deux ont 60 mm de focale) 1. L3 est monté dans un plan conjugué au plan focal arrière de l&#39;objectif. L3 mont sur une platine de positionnement de précision XYZ pour permettre de direction de faisceau. Il est utile pour la phase XYZ de disposer d&#39;indicateurs numériques pour ses micromètres, ce qui permet un positionnement répétable et le repositionnement de la trappe. La «plage de déplacement 0,5 est généralement suffisant, mais plus voyager pour le positionnement L3 long de l&#39;axe optique peut être utile. Utilisez faisceau du pointeur laser visible (voir section 1.6) pour assurer le placement de la lentille et l&#39;alignement approximatif. </li></ol> 2. Installation du détecteur laser <ol><li> Installez le DM3 miroir dichroïque dessus du condenseur comme le montre la figure 1. Un support personnalisé est généralement requis. Fixer la photodiode quadruple (DOU) ou un détecteur sensible à la position (PSD) 8 sur le côté de l&#39;assemblage de condenseur et ensure que le faisceau laser 980 nm traduit par DM3 est frappant c&#39;est à peu près au centre. Lors de l&#39;utilisation DOU, veiller à ce que il est monté sur une petite scène XY pour permettre le centrage précis de la sonde sur le faisceau laser. </li><li> Installation L1 (typiquement une lentille de 30 mm) entre le capteur et DM3. L1 de position de manière à focaliser le faisceau à un seul point sur le capteur. </li><li> Installer le filtre coupe-bande, juste avant L1 pour bloquer le faisceau de 1064 nm, ainsi que toutes les réflexions parasites de lumière visible à partir de l&#39;illuminateur de microscope et l&#39;éclairage ambiant. </li></ol> 3. Installation de 1,064 nm de longueur d&#39;onde holographique Piège <ol><li> La partie holographique de l&#39;installation est construite autour d&#39;un ensemble matériel / logiciel disponible dans le commerce Les miroirs holographiques utilisés dans ce paquet sont évalués à un maximum de puissance incidente de 5 ou 10 W / cm 2. Monomodes TEM00 poutres dans cette gamme de puissance peuvent être facilement proviennent d&#39;un laser DPSS à 1,064 longueur d&#39;onde nm. </li><li> Montez le laser 1064 nm sur une élévationplate-forme pour correspondre à peu près à la hauteur de la trajectoire du faisceau de la ligne 980 (voir section 1). </li><li> Si ce n&#39;est pas directement contrôlable, la puissance du laser peut être réglé manuellement par l&#39;installation d&#39;une plaque demi-onde (HWP) et un polariseur (PBS) juste après l&#39;ouverture de sortie du laser. Il est utile de monter le polariseur dans un étage rotatif pour être en mesure de faire correspondre exigence de miroir holographique de polarisation du faisceau. </li><li> Installez le nm élargisseur de faisceau 1,064 (L6 et L7). La taille du faisceau laser doit être élargie pour correspondre à la diagonale du miroir holographique. Pour des taux d&#39;expansion grandes (au-dessus de 10X), il peut être une préoccupation de maintenir la taille de l&#39;extenseur petit. Ainsi, il peut être souhaitable d&#39;utiliser des lentilles avec inhabituellement faible distance focale (ici: 16 mm et 175 mm). </li><li> Installez les autres miroirs comme indiqué pour diriger le faisceau de 1,064 nm à travers l&#39;objectif. <ol><li> Sécurisé DM1 dichroïque (45 ° d&#39;angle d&#39;incidence) dans une monture cinématique et placer l&#39;ensemble dans le trajet de faisceau de 980 nm de sorte qu&#39;il permet de undiminishetransmission d de ce faisceau. </li><li> Activez la lumière de pointeur laser. Le miroir DM1 doit refléter une quantité suffisante de lumière visible afin de positionner correctement le modulateur spatial de lumière (SLM), sur le trajet de ce faisceau. Le SLM doit également être incliné de sorte que les faisceaux laser entrants et sortants sont aussi proches que possible de l&#39;incidence normale. Toutefois l&#39;angle d&#39;incidence doit être suffisamment grand pour que le faisceau laser ne soit pas coupé par les montures de lentille et d&#39;autres composants optiques. Un angle de 5 ° devrait être facilement réalisable et est suffisamment petit. Enfin, la distance de DM1 au SLM doit être mesuré avec précision pour que l&#39;insertion des lentilles L4 et L5 (voir 3.6 ci-dessous) peut conjuguer le plan de miroir SLM et le plan focal arrière de l&#39;objectif. </li><li> Installation d&#39;un miroir pour diriger la lumière à partir de 1064 nm élargisseur de faisceau au SLM. Assurez-vous que la lumière du pointeur laser frappe l&#39;ouverture d&#39;élargisseur de faisceau au centre. </li></ol></li><li> Installez lentilles L4 et L5 (ici: lentilles avec 125 mm et 200 mm respectivement). Cette paire de lunette conjugue le plan de miroir SLM au plan focal arrière de l&#39;objectif et permet également de réduire la taille du faisceau à seulement légèrement déborder le retour de l&#39;ouverture de l&#39;objectif. Nous avons choisi des focales longues à l&#39;espace du SLM loin de DM1. Ce n&#39;est pas seulement efface place à la deuxième ligne de laser, mais tend aussi à rendre plus facile l&#39;alignement. </li><li> Retirez le pointeur laser. Laissez l&#39;adaptateur de montage pour servir ouverture d&#39;alignement grossier. </li></ol> 4. Installation et alignement Notes de système <ol><li> Lentille L3 et SLM doivent être positionnés de manière à être optiquement conjugué au plan focal arrière de l&#39;objectif. Le point focal commun de L4 et L5 est optiquement conjugué au plan de l&#39;échantillon si les faisceaux de piégeage optique sont injectés dans l&#39;espace de débordement du microscope. </li><li> chanter IR carte spectateur aligner le faisceau de 980 nm pour aller le long de l&#39;axe central de l&#39;ouverture dans l&#39;adaptateur de pointeur laser. </li><li> Utilisez la carte IR to faire en sorte que le faisceau de 1064 nm frappe au même endroit que le faisceau de 980 nm à DM1, L2 et L3 et que le faisceau de 1064 nm va le long de l&#39;axe central de l&#39;ouverture dans l&#39;adaptateur de pointeur laser. </li><li> Remplacer l&#39;adaptateur de montage pointeur laser avec un objectif. Numérique huile ou d&#39;eau objectif d&#39;ouverture élevé est typique. </li><li> Aligner le piège à 980 nm tel que décrit dans neuf par &quot;marche&quot; du faisceau laser jusqu&#39;à ce qu&#39;un motif d&#39;interférence radialement symétrique est visible sur la caméra. </li><li> Avec l&#39;arrêt de miroir holographique (ie agissant comme un miroir passive) utiliser SLM et DM1 de «marcher» le faisceau diffracté 1,064 nm pour aligner le piège de 1,064 nm. </li><li> Le SLM produit un faisceau non diffracté importante qui se traduit par une forte piège laser immobile dans le champ de vision. Ceci est utile pour l&#39;alignement, mais peut-être pas souhaitable pour des expériences. Pour bloquer ce piège, on peut insérer un petit objet opaque dans le trajet de la lumière non diffractée dans le conjugué de l&#39;emplacement par rapport au plan de l&#39;échantillon (par exemple ee point focal commun de L4 et L5). La taille de ce bloqueur de tache centrale doit être un peu plus grand que le diamètre de la tache d&#39;Airy pour la lumière focalisée (un bloqueur de 100-300 um de diamètre pour le système décrit). </li><li> djust 1,064 polarisation du faisceau nm en utilisant le filtre pour correspondre à l&#39;orientation SLM. Faire pivoter la lame demi-onde pour régler la puissance de sortie du faisceau si besoin. </li><li> Si vous le souhaitez, insérez AOD ou NEM éléments de direction faisceau dans la ligne de laser 980 nm. Veiller à la bonne conjugaison de ces éléments au plan focal arrière de l&#39;objectif et de réaligner le piège. Il est utile de monter les éléments de direction sur une scène de goniométrie. </li></ol>

<ol>
	<li>Svoboda, K., Block, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+applications+of+optical+forces.">Biological applications of optical forces.</a> Annu. Rev. Biophys. Biomol. Struct. 23, 247-285 (1994).</li><li>Ashkin, A., Schutze, K., Dziedzic, J. M., Euteneuer, U., Schliwa, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Force+generation+of+organelle+transport+measured+in+vivo+by+an+infrared+laser+trap.">Force generation of organelle transport measured in vivo by an infrared laser trap.</a> Nature. 348, 346-348 (1990).</li><li>Shubeita, G. T., Tran, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consequences+of+motor+copy+number+on+the+intracellular+transport+of+kinesin-1-driven+lipid+droplets.">Consequences of motor copy number on the intracellular transport of kinesin-1-driven lipid droplets.</a> Cell. 135, 1098-1107 (2008).</li><li>Polin, M., Ladavac, K., Lee, S. H., Roichman, Y., Grier, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimized+holographic+optical+traps.">Optimized holographic optical traps.</a> Opt Express. 13, 5831-5845 (2005).</li><li>Sun, B., Roichman, Y., Grier, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theory+of+holographic+optical+trapping.">Theory of holographic optical trapping.</a> Opt. Express. 16, 15765-15776 (2008).</li><li>Moffitt, J. R., Chemla, Y. R., Smith, S. B., Bustamante, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+optical+tweezers.">Recent advances in optical tweezers.</a> Annu. Rev. Biochem. 77, 205-228 (2008).</li><li>Grier, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+revolution+in+optical+manipulation.">A revolution in optical manipulation.</a> Nature. 424, 810-816 (2003).</li><li>Neuman, K. C., Block, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+trapping.">Optical trapping.</a> Rev. Sci. Instrum. 75, 2787-2809 (2004).</li><li>Sheetz, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+tweezers+in+cell+biology.">Laser tweezers in cell biology.</a> Introduction. Methods Cell Biol. 55, xi-xii (1998).</li><li>Spudich, J. A., Rice, S. E., Rock, R. S., Purcell, T. J., Warrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+traps+to+study+properties+of+molecular+motors.">Optical traps to study properties of molecular motors.</a> Cold Spring Harb. Protoc. 2011, 1305-1318 (2011).</li><li>Visscher, K., Gross, S. P., Block, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+of+multiple-beam+optical+traps+with+nanometer-resolution+position+sensing.+Selected+Topics+in+Quantum+Electronics.">Construction of multiple-beam optical traps with nanometer-resolution position sensing. Selected Topics in Quantum Electronics.</a> IEEE Journal of. 2, 1066-1076 (1996).</li><li>Valentine, M. T., Guydosh, N. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+steering+of+an+optical+trap+by+electro-optic+deflection.">Precision steering of an optical trap by electro-optic deflection.</a> Opt Lett. 33, 599-601 (2008).</li></ol>

Les auteurs n&#39;ont rien à révéler.

Nous avons construit un instrument qui combine deux pièges optiques de différents types (Figure 1) pour fournir des installations de piégeage séparés pour la manipulation d&#39;objets et de mesure. Le piège optique &quot;classique&quot; est construit autour d&#39;une diode laser à 980 nm. Ce faisceau est élargi, dirigé et ensuite injecté dans notre microscope inversé (poutre &quot;lumière rouge&quot; dans la figure 1). Le piège optique holographique est construit autour d&#...

Piégeage optique est l&#39;une des techniques clés en biophysique 6. Un progrès important dans le piégeage optique a été le développement de pièges holographiques qui permettent la création de modèles de piégeage en trois dimensions plutôt que les pièges de points classiques 7. Ces pièges holographiques possèdent l&#39;avantage de la polyvalence dans le positionnement des objets de réfraction. Cependant pièges classiques peuvent être facilement alignées est plus symétrique que les kits holographiques disponibles dans le commerce. Ils permettent également pour le suivi rapide et précis des objets piégés. Ici, nous décrivons un système (Figure 1) qui combine les deux approches de piégeage dans un seul instrument et permet à l&#39;utilisateur d&#39;exploiter les avantages des deux, selon le cas. Les considérations générales de la construction de pièges optiques (basé sur des faisceaux laser unique ou multiple) sont discutés en détail ailleurs 8-10. Ici, nous décrivons les considérations spécifiques à notre sEtup et fournir les détails de notre procédure d&#39;alignement. Par exemple, les systèmes avec deux faisceaux de piégeage optique ont été décrits précédemment (par exemple ref. 11), typiquement en utilisant un faisceau laser pour piéger un objet de réfraction et à l&#39;aide de l&#39;autre (faisceau de puissance intentionnellement bas) pour la lecture découplé de la position de l&#39;objet piégé . Ici cependant, les deux faisceaux laser doivent être de haute puissance (300 mW ou ultérieure) parce que les deux doivent être utilisés pour le piégeage. Pour les mesures des systèmes biologiques, les lasers utilisés pour le piégeage devraient baisser de façon optimale dans une fenêtre NIR spécifique de longueur d&#39;onde afin de minimiser la dégradation des protéines induite par la lumière 1. Ici, nous avons choisi d&#39;utiliser 980 diode nm et 1064 nm lasers DPSS en raison de leur faible coût, de haute disponibilité et de facilité d&#39;utilisation. Nous avons également choisi d&#39;utiliser un modulateur spatial de lumière (SLM) de créer et de manipuler plusieurs pièges simultanément en temps réel 4,5. Ces dispositifs sont disponibles dans le commercemais leur intégration dans une installation complète présente des défis uniques. Nous décrivons ici une approche pratique qui aborde ces difficultés potentielles et fournit un instrument très polyvalent. Nous donnons un exemple explicite de la configuration spécifique décrite qui peut être utilisé comme un guide pour les dessins modifiés.

<table border="1">
	<tbody>
		<tr>
			<td>Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Optical table</td>
			<td>Newport corporation</td>
			<td>ST-UT2-56-8</td>
			<td>Irvine, CA</td>
		</tr>
		<tr>
			<td>Microscope, Inverted, Eclipse Ti</td>
			<td>Nikon USA</td>
			<td>MEA53220</td>
			<td>Melville, NY</td>
		</tr>
		<tr>
			<td>Plan apo 100X oil objective (1.4 NA)</td>
			<td>Nikon USA</td>
			<td>MRD01901</td>
			<td>Melville, NY</td>
		</tr>
		<tr>
			<td>Oil condenser Lens 1.4 NA</td>
			<td>Nikon USA</td>
			<td>MEL41410</td>
			<td>Melville, NY</td>
		</tr>
		<tr>
			<td>EMCCD camera</td>
			<td>Andor technology USA</td>
			<td>Ixon DU897</td>
			<td>South Windsor, CT</td>
		</tr>
		<tr>
			<td>1/3" CCD IEEE1394 camera</td>
			<td>NET USA Inc</td>
			<td>Foculus FO124SC</td>
			<td>Highland IN</td>
		</tr>
		<tr>
			<td>Laser, TEM00, SLM, 1,064 nm wavelength</td>
			<td>Klastech Laser Technologies</td>
			<td>Senza-1064-1000</td>
			<td>Dortmund; Germany</td>
		</tr>
		<tr>
			<td>laser diode, TEM00, SLM, 980 nm</td>
			<td>Axcel Photonics</td>
			<td>BF-979-0300-P5A</td>
			<td>Marlborough, MA</td>
		</tr>
		<tr>
			<td>laser diode mount</td>
			<td>ILX Lightwave</td>
			<td>LDX-3545, LDT-5525, and LDM-4984</td>
			<td>Bozeman, MT</td>
		</tr>
		<tr>
			<td>adjustable fiber ports</td>
			<td>Thorlabs</td>
			<td>PAF-X-11-B</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>holographic system</td>
			<td>Arryx</td>
			<td>HOTKIT-ADV-1064</td>
			<td>Chicago, IL</td>
		</tr>
		<tr>
			<td>holographic mirror</td>
			<td>Boulder Non-linear Systems</td>
			<td>this is a part of HOTKIT-ADV-1064</td>
			<td>Lafayette, CO</td>
		</tr>
		<tr>
			<td>Calcite polarizer</td>
			<td>Thorlabs</td>
			<td>GL10-B</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>half-wave plate</td>
			<td>Thorlabs</td>
			<td>WPH05M-1064</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>Polarizer rotation mount</td>
			<td>Thorlabs</td>
			<td>PRM1</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>half-wave plate rotation mount</td>
			<td>Thorlabs</td>
			<td>RSP1</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>Shutter</td>
			<td>Thorlabs</td>
			<td>SH05</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>dichroic mirrors (DM2 &amp; DM3); 45&deg; AOI</td>
			<td>Chroma Technology</td>
			<td>t750spxrxt</td>
			<td>Bellows Falls, VT</td>
		</tr>
		<tr>
			<td>dichroic mirror (DM1); 45&deg; AOI</td>
			<td>Thorlabs</td>
			<td>DMSP1000R</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>custom mechanical adapter</td>
			<td>Thorlabs</td>
			<td>SM1A11 and AD12F with enlarged inner bore</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>notch filter</td>
			<td>Semrock</td>
			<td>FF01-850/310-25</td>
			<td>Rochester, NY</td>
		</tr>
		<tr>
			<td>Acousto-Optic deflector (2-axis)</td>
			<td>intraAction</td>
			<td>DTD-584CA28</td>
			<td>Bellwood, IL</td>
		</tr>
		<tr>
			<td>goniometric stage</td>
			<td>New Focus</td>
			<td>9081</td>
			<td>Santa Clara, CA</td>
		</tr>
		<tr>
			<td>60 mm steering lenses</td>
			<td>Thorlabs</td>
			<td>LA1134-B</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>16 mm aspherical expander lens</td>
			<td>Thorlabs</td>
			<td>AC080-016-C</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>175 mm expander lens</td>
			<td>Thorlabs</td>
			<td>LA1229-C</td>
			<td>Newton, NJ</td>
		</tr>
		<tr>
			<td>Spot blocker (cabron-steel sphere)</td>
			<td>Bal-Tec</td>
			<td>0.0100" diameter</td>
			<td>Los Angeles, CA</td>
		</tr>
		<tr>
			<td>Microspheres (Carboxyl-polystyrene)</td>
			<td>Spherotech</td>
			<td>CP-45-10</td>
			<td>Lake Forest, IL</td>
		</tr>
	</tbody>
</table>

construction of a high resolution microscope with conventional and holographic optical trapping capabilities

Systèmes de microscope à haute résolution avec des pièges optiques permettent la manipulation précise d&#39;objets divers de réfraction, tels que des billes diélectriques 1 ou organites cellulaires 2,3, ainsi que pour la haute lecture de la résolution spatiale et temporelle de leur position par rapport au centre du piège. Le système décrit ici a un tel &quot;traditionnel&quot; piège fonctionnant à 980 nm. Il fournit en outre un second système de piégeage optique qui utilise un ensemble holographique disponible dans le commerce afin de créer et de manipuler simultanément les modèles de piégeage complexes dans le champ de vision du microscope 4,5 à une longueur d&#39;onde de 1064 nm. La combinaison des deux systèmes permet la manipulation de plusieurs objets de réfraction en même temps tout en menant simultanément une vitesse élevée et mesures à haute résolution du mouvement et de la production de force au nanomètre et l&#39;échelle de piconewton.

La configuration assemblée permet à l&#39;opérateur de piéger plusieurs objets de réfraction en temps réel et les positionner dans les trois dimensions dans le champ de vision. Nous illustrons les capacités holographiques de l&#39;instrument en piégeant 11 microsphères (figure 2). Le piège confinant chaque objet est manuellement repositionné sur le piégeage de sorte que l&#39;arrangement final représente le logo de l&#39;Université de l&#39;Utah, où cette expérience a été réalisée. U...

Watch this Scientific Journal Video about Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities at JoVE.com

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

Le système décrit ici utilise un piège optique traditionnel ainsi qu&#39;une ligne de piégeage optique holographique indépendant, capable de créer et de manipuler de multiples pièges. Cela permet la création d&#39;arrangements géométriques complexes de particules réfraction tout en permettant à grande vitesse des mesures simultanées à haute résolution, de l&#39;activité des enzymes biologiques.

Construction d&#39;un microscope à haute résolution avec des capacités de piégeage optique classique et holographique

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

construction-high-resolution-microscope-with-conventional-holographic

Research

JoVE Journal

Engineering

12.0K vues.  University of Utah. Le système décrit ici utilise un piège optique traditionnel ainsi qu'une ligne de piégeage optique holographique indépendant, capable de créer et de manipuler de multiples pièges. Cela permet la création d'arrangements géométriques complexes de particules réfraction tout en permettant à grande vitesse des mesures simultanées à haute résolution, de l'activité des enzymes biologiques.

Vidéo: Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

Base de silicium polycristallin à couche mince des cellules solaires avec plasmonique amélioré par Light-piégeage

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

Recherche

Ingénierie

Construction and Testing of Coin Cells of Lithium Ion Batteries

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have also been considered to be used in electric and hybrid vehicles1 or even electrical grid stabilization systems2. All these applications simulate a dramatic increase in the research and development of battery materials3-7, including new materials3,8, doping9, nanostructuring10-13, coatings or surface modifications14-17 and novel binders18. Consequently, an increasing number of physicists, chemists and materials scientists have recently ventured into this area. Coin cells are widely used in research laboratories to test new battery materials; even for the research and development that target large-scale and high-power applications, small coin cells are often used to test the capacities and rate capabilities of new materials in the initial stage. 
 In 2010, we started a National Science Foundation (NSF) sponsored research project to investigate the surface adsorption and disordering in battery materials (grant no. DMR-1006515). In the initial stage of this project, we have struggled to learn the techniques of assembling and testing coin cells, which cannot be achieved without numerous help of other researchers in other universities (through frequent calls, email exchanges and two site visits). Thus, we feel that it is beneficial to document, by both text and video, a protocol of assembling and testing a coin cell, which will help other new researchers in this field. This effort represents the "Broader Impact" activities of our NSF project, and it will also help to educate and inspire students.
In this video article, we document a protocol to assemble a CR2032 coin cell with a LiCoO2 working electrode, a Li counter electrode, and (the mostly commonly used) polyvinylidene fluoride (PVDF) binder. To ensure new learners to readily repeat the protocol, we keep the protocol as specific and explicit as we can. However, it is important to note that in specific research and development work, many parameters adopted here can be varied. First, one can make coin cells of different sizes and test the working electrode against a counter electrode other than Li. Second, the amounts of C black and binder added into the working electrodes are often varied to suit the particular purpose of research; for example, large amounts of C black or even inert powder were added to the working electrode to test the "intrinsic" performance of cathode materials14. Third, better binders (other than PVDF) have also developed and used18. Finally, other types of electrolytes (instead of LiPF6) can also be used; in fact, certain high-voltage electrode materials will require the uses of special electrolytes7.

A protocol to construct and test coin cells of lithium ion batteries is described. The specific procedures of making a working electrode, preparing a counter electrode, assembling a cell inside a glovebox and testing the cell are presented.

Construction et d&#39;essai des Piles de batteries lithium-ion

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime.  Lithium ion ...

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

Le piégeage optique de nanoparticules

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats &amp; Spheres

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~&#955;/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.

A novel optical polishing process, called &#8220;Convergent Polishing&#8221;, which enables faster, lower cost polishing, is described. Unlike conventional polishing processes, Convergent Polishing allows a glass workpiece to be polished in a single iteration and with high surface quality to its final surface figure without requiring changes to polishing parameters.

Convergent Polissage: un simple, processus rapide, pleine ouverture de polissage de haute qualité optiques Flats &amp; Sphères

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial ...

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

We present a compact reflection digital holographic system (CDHM) for inspection and characterization of MEMS devices. A lens-less design using a diverging input wave providing natural geometrical magnification is demonstrated. Both static and dynamic studies are presented.

Compact numérique Holographic Microscope pour les MEMS Inspection et caractérisation de Lens-moins

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...

Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few can observe immobilized particles. Moreover, a limited number of studies have experimentally measured the exertable forces on the particles. The designs can be classified as the protruding nanodisk type or the suppressed nanohole type. For the latter, microscopic observation is extremely challenging. In this paper, a new plasmonic tweezer system is introduced to monitor particles, both in directions parallel and orthogonal to the symmetric axis of a plasmonic nanohole structure. This feature enables us to observe the movement of each particle near the rim of the nanohole. Furthermore, we can quantitatively estimate the maximal trapping forces using a new fluidic channel.

A microchip fabrication process that incorporates plasmonic tweezers is presented here. The microchip enables the imaging of a trapped particle to measure maximal trapping forces.

Plasmonique et Piégeage Libération de Nanoparticules dans un environnement de surveillance

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few ...

Demonstration of a Hyperlens-integrated Microscope and Super-resolution Imaging

The use of super-resolution imaging to overcome the diffraction limit of conventional microscopy has attracted the interest of researchers in biology and nanotechnology. Although near-field scanning microscopy and superlenses have improved the resolution in the near-field region, far-field imaging in real-time remains a significant challenge. Recently, the hyperlens, which magnifies and converts evanescent waves into propagating waves, has emerged as a novel approach to far-field imaging. Here, we report the fabrication of a spherical hyperlens composed of alternating silver (Ag) and titanium oxide (TiO2) thin layers. Unlike a conventional cylindrical hyperlens, the spherical hyperlens allows for two-dimensional magnification. Thus, incorporation into conventional microscopy is straightforward. A new optical system integrated with the hyperlens is proposed, allowing for a sub-wavelength image to be obtained in the far-field region in real time. In this study, the fabrication and imaging setup methods are explained in detail. This work also describes the accessibility and possibility of the hyperlens, as well as practical applications of real-time imaging in living cells, which can lead to a revolution in biology and nanotechnology.

The use of a hyperlens has been regarded as a novel super-resolution imaging technique due to its advantages in real-time imaging and its simple implementation with conventional optics. Here, we present a protocol describing the fabrication and imaging applications of a spherical hyperlens.

Démonstration d’un Microscope intégré Hyperlens et Super-resolution Imaging

The use of super-resolution imaging to overcome the diffraction limit of conventional microscopy has attracted the interest of researchers in biology and ...

Method for Recording Broadband High Resolution Emission Spectra of Laboratory Lightning Arcs

Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional camera film methods and then digital camera technology, from which several important characteristics have been derived. However, such work has always been limited due to the inherently random and non-repeatable nature of natural lightning events in the field. Recent developments in lightning test facilities now allow the reproducible generation of lightning arcs within controlled laboratory environments, providing a test bed for the development of new sensors and diagnostic techniques to understand lightning mechanisms better. One such technique is a spectroscopic system using digital camera technology capable of identifying the chemical elements with which the lightning arc interacts, with these data then being used to derive further characteristics. In this paper, the spectroscopic system is used to obtain the emission spectrum from a 100 kA peak, 100 &#181;s duration lightning arc generated across a pair of hemispherical tungsten electrodes separated by a small air gap. To maintain a spectral resolution of less than 1 nm, several individual spectra were recorded across discrete wavelength ranges, averaged, stitched, and corrected to produce a final composite spectrum in the 450 nm (blue light) to 890 nm (near infrared light) range. Characteristic peaks within the data were then compared to an established publicly available database to identify the chemical element interactions. This method is readily applicable to a variety of other light emitting events, such as fast electrical discharges, partial discharges, and sparking in electrical equipment, apparatus, and systems.

Emission spectroscopy techniques have traditionally been used to analyze inherently random lightning arcs occurring in nature. In this paper, a method developed to obtain the emission spectroscopy from reproducible lightning arcs generated within a laboratory environment is described.

Méthode d'enregistrement des spectres d'émission à haute résolution à large bande des arcs de foudre de laboratoire

Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional ...

Single-Digit Nanometer Electron-Beam Lithography with an Aberration-Corrected Scanning Transmission Electron Microscope

We demonstrate extension of electron-beam lithography using conventional resists and pattern transfer processes to single-digit nanometer dimensions by employing an aberration-corrected scanning transmission electron microscope as the exposure tool. Here, we present results of single-digit nanometer patterning of two widely used electron-beam resists: poly (methyl methacrylate) and hydrogen silsesquioxane. The method achieves sub-5 nanometer features in poly (methyl methacrylate) and sub-10 nanometer resolution in hydrogen silsesquioxane. High-fidelity transfer of these patterns into target materials of choice can be performed using metal lift-off, plasma etch, and resist infiltration with organometallics.

We use an aberration-corrected scanning transmission electron microscope to define single-digit nanometer patterns in two widely-used electron-beam resists: poly (methyl methacrylate) and hydrogen silsesquioxane. Resist patterns can be replicated in target materials of choice with single-digit nanometer fidelity using liftoff, plasma etching, and resist infiltration by organometallics.

Lithographie de faisceau d’électrons à un seul chiffre nanomètre avec une correction de l’Aberration Transmission Microscope électronique à balayage

We demonstrate extension of electron-beam lithography using conventional resists and pattern transfer processes to single-digit nanometer dimensions by ...