El financiamiento fue proporcionado por la Universidad de Utah. Nos gustaría dar las gracias al Dr. J. Xu (UC Merced) y Dr. Reddy BJN (UC Irvine) útil para los debates.

1. La instalación de 980 nm Longitud de onda única trampa óptica <ol><li> Trampas ópticas a 980 nm de longitud de onda es a menudo óptima para experimentos biofísica y diodos láser de bajo costo están disponibles con una salida de potencia de hasta 300 mW. Es preferible que un láser de diodo que se trenza con la polarización de preservación de fibra monomodo con un diámetro de campo de modo conocido. La fibra tiene que ser suficientemente largo para actuar como un filtro de modo y por lo general se termina ya sea con una FC / PC o conector FC / APC. De éstos, es preferible minimizar la reflexión posterior de luz y el potencial de inestabilidades de retroalimentación FC / APC. </li><li> Asegure el diodo láser 980 nm en un montaje que permite el poder y control de temperatura. Lo mejor es fijar el soporte a una mesa óptica directamente a maximizar la disipación de calor pasiva y así minimizar el riesgo de fracaso del diodo debido a un mal funcionamiento del controlador de temperatura. </li><li> Monte el conector de fibra PC / APC a los colimadores ópticas de haz. Escrítico para asegurar que el haz colimado tiene divergencia angular mínima para puertos de fibra ajustables son más útiles. Asegúrese de que el puerto de fibra elegida coincide con el diámetro del campo modal de la fibra de la coleta del diodo. Si el haz es para ser rastered utilizando deflectores acústico-ópticos (AOD) o deflectores electro-ópticos (EOD), entonces la cintura del haz láser colimado también debe ser ligeramente menor que el tamaño de la abertura del deflector. </li><li> Fije el adaptador de colimación a la mesa óptica a distancia suficiente del microscopio para permitir el enrutamiento de haz, la expansión, y la colocación de otros componentes deseados. Ajuste el puerto de fibra para asegurar cintura del haz consistente en distancias comparables a la trayectoria de haz total al microscopio. </li><li> Instalar espejos indicados en la Figura 1. Retire el objetivo del microscopio y el uso de los espejos para dirigir el haz a través de la abertura en la etapa de montaje de objetivo. Si se prefiere, la colocación de los espejos dicroicos DM1 y DM3 se puede omitir hastamás tarde. DM2 y DM3 son tanto paso corto y transmitir la luz visible, mientras que refleja IR cercano y más. </li><li> Es útil para montar temporalmente un puntero láser rojo en lugar del objetivo, alineados en el eje óptico del microscopio. Un adaptador mecánico personalizado es necesario para asegurar el centrado del puntero láser. Haz visible desde el puntero láser a continuación, se puede encaminar de nuevo al centro de la abertura del puerto de fibra y luego se puede utilizar para instalar los lentes (ver más abajo). </li><li> Instalar el expansor de haz 980 nm (L8 y L9) a una distancia adecuada desde el puerto de fibra para permitir la inserción futuro de componentes de la dirección (AOD o EOD) según sea necesario 1. La viga mayor, tiene que llenar demasiado poco la apertura focal posterior del objetivo. (Aquí, las lentes con distancias focales de 125 mm y 60 mm están en una disposición kepleriano a aproximadamente el doble de la cintura del haz). Utilice la luz de puntero láser visible (ver sección 1.6) para asegurar la colocación apropiada de la lente y la alineación aproximada. </li><li> Instalarl de las lentes de dirección 980 nm (L2 y L3) en una disposición de telescopio, como se indica (en este caso ambos tienen longitud focal 60 mm) 1. L3 se monta en un plano conjugado al plano de back-focal del objetivo. Montaje de L3 en una etapa de posicionamiento XYZ precisión para permitir la orientación del haz. Es útil para la etapa de XYZ contar con indicadores digitales para sus micrómetros, lo que permite un posicionamiento repetible y el reposicionamiento de la trampa. El &quot;rango de desplazamiento 0.5 suele ser suficiente, sin embargo ya viajes para el posicionamiento L3 a lo largo del eje óptico puede ser útil. Utilice puntero láser visible (ver sección 1.6) para asegurar la colocación apropiada de la lente y la alineación aproximada. </li></ol> 2. La instalación del detector de láser <ol><li> Instalar el espejo dicroico DM3 encima del condensador, como se muestra en la Figura 1. Normalmente se requiere un montaje personalizado. Asegure el fotodiodo cuádruple (QPD) o un detector sensible a la posición (PSD) 8 hacia el lado del conjunto de condensador y ensure que el rayo láser 980 nm refleja en DM3 está golpeando es más o menos en el centro. Cuando se utiliza QPD, asegurarse de que está montado en una pequeña etapa de XY para permitir el centrado exacto del sensor en el haz de láser. </li><li> Instalar L1 (típicamente una lente de 30 mm) entre DM3 y el sensor. Posición L1 para enfocar el haz a un solo punto del sensor. </li><li> Instalar el filtro de muesca justo antes de L1 para bloquear el haz de 1064 nm, así como cualquier reflexión de luz visible callejeros del iluminador microscopio y la iluminación ambiente. </li></ol> 3. La instalación de 1.064 nm de longitud de onda holográfica Trampa <ol><li> La parte holográfica de la instalación se construye en torno a un paquete de hardware / software disponible en el mercado Los espejos holográficos utilizados en este paquete están clasificados para una potencia máxima de incidencia de 5 a 10 W / cm 2. Monomodo TEM00 vigas en este rango de potencia pueden ser fácilmente obtienen de un láser DPSS a 1064 nm de longitud de onda. </li><li> Montar el láser 1064 nm en un elevadoplataforma para que coincida con la altura de la trayectoria del haz de la línea 980 (véase la sección 1). </li><li> Si no directamente controlable, la potencia del láser se puede ajustar manualmente mediante la instalación de una placa de media onda (PMR) y un polarizador (PBS) inmediatamente después de la abertura de salida del láser. Es útil para montar el polarizador en una etapa rotatoria para ser capaz de igualar requisito espejo holográfico para la polarización del haz. </li><li> Instale el 1,064 nm expansor de haz (L6 y L7). La cintura del haz láser debe ser ampliado para que coincida con el tamaño de la diagonal del espejo holográfico. Para grandes relaciones de expansión (por encima de 10 veces) que puede ser una preocupación para mantener el tamaño del expansor pequeña. Por lo tanto, puede ser deseable usar lentes con distancia focal inusualmente pequeña (aquí: 16 mm y 175 mm). </li><li> Instalar los otros espejos como se indica para dirigir el haz de 1.064 nm a través del objetivo. <ol><li> Secure DM1 dicroico (45 ° ángulo de incidencia) en una montura cinemática y colocar el conjunto en la trayectoria del haz de 980 nm de modo que permite undiminishetransmisión d de que el haz. </li><li> Activar luz de puntero láser. El espejo DM1 debe reflejar la suficiente cantidad de luz visible para colocar correctamente el modulador espacial de luz (SLM) en la trayectoria de este haz. El SLM también tiene que ser en ángulo de manera que los haces de láser entrantes y salientes están tan cerca como sea posible a la incidencia normal. Sin embargo, el ángulo de incidencia debe ser suficientemente grande para asegurar que el rayo láser no se recorta por montajes de lentes y otros componentes ópticos. Un ángulo de 5 ° debe ser fácil de lograr y es lo suficientemente pequeño. Por último la distancia desde DM1 al SLM deberá medirse con precisión de manera que la inserción de las lentes de L4 y L5 (ver 3.6 más abajo) puede conjugar el plano de simetría de SLM y el plano posterior-focal del objetivo. </li><li> Instale un espejo para dirigir la luz desde 1064 expansor de haz nm para el SLM. Asegúrese de que la luz del puntero láser incide en el expansor de apertura del haz en el centro. </li></ol></li><li> Instale lentes de L4 y L5 (en este caso las lentes con 125 mm y 200 mm, respectivamente). Este par telescopio conjuga el plano de simetría SLM con el plano focal posterior del objetivo y también reduce la cintura del haz de sobrellenado sólo ligeramente de la abertura trasera del objetivo. Elegimos objetivos con distancias focales largas para separar el SLM lejos de DM1. Esto no sólo elimina espacio para la segunda línea de láser, pero también tiende a hacer más fácil la alineación. </li><li> Retire el puntero láser. Deje el adaptador de montaje para servir como abertura de alineación aproximada. </li></ol> 4. Instalación y alineación Notas sobre el sistema <ol><li> Lente L3 y SLM deben estar colocados de forma que sea ópticamente conjugada con el plano focal posterior del objetivo. El punto focal común de L4 y L5 es ópticamente conjugado con el plano de la muestra si los haces ópticos de captura no se inyectan en el espacio infinito del microscopio. </li><li> cantar Tarjeta de infrarrojos visor de alinear el haz de 980 nm para ir a lo largo del eje central de la abertura en el adaptador de puntero láser. </li><li> Utilice IR tarjeta de to asegurarse de que el haz de 1064 nm golpea en el mismo lugar que el haz de 980 nm en DM1, L2, y L3 y que el haz de 1064 nm va a lo largo del eje central de la abertura en el adaptador de puntero láser. </li><li> Vuelva a colocar el adaptador de montaje puntero láser con un objetivo. Aceite o agua objetiva apertura numérica alta es típico. </li><li> Alinear la trampa 980 nm como se describe en el 9 por &quot;caminar&quot; el rayo láser hasta que un patrón de interferencia radial simétrica se ve en la cámara. </li><li> Con el espejo holográfico off (es decir, actúa como un espejo pasivo) utilizar SLM y DM1 a &quot;caminar&quot; el haz no difractado 1064 nm para alinear la trampa de 1.064 nm. </li><li> El SLM produce un haz no difractado significativa que se traduce en una fuerte trampa láser inamovible en el campo de visión. Esto es útil para la alineación, pero puede no ser deseable para los experimentos. Para bloquear esta trampa se puede insertar un pequeño objeto opaco en el camino de la luz no difractada en el conjugado de ubicación con respecto al plano de la muestra (por ejemplo, thpunto focal común e de L4 y L5). El tamaño de este bloqueador de punto central tiene que ser algo mayor que el diámetro del disco de Airy para la luz enfocada (un bloqueador con 100-300 m de diámetro para el sistema descrito). </li><li> JUSTE 1064 la polarización del haz nm usando el polarizador para que coincida con la orientación SLM. Gire la placa de media onda para ajustar la potencia de salida del haz lo deseas. </li><li> Si lo desea, introduzca AOD o EOD elementos de orientación del haz en la línea de láser 980 nm. Asegúrese de conjugación adecuada de estos elementos para el avión de vuelta-focal del objetivo y volver a alinear la trampa. Es útil para montar los elementos de dirección en un escenario goniométrica. </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>

Los autores no tienen nada que revelar.

Hemos construido un instrumento que combina dos trampas ópticas de diferentes tipos (Figura 1) para proporcionar instalaciones de captura separadas para la manipulación de objetos y medición. La trampa óptica &quot;convencional&quot; se basa en un láser de diodo de 980 nm. Este haz se expande, dirigió y luego se inyecta en el microscopio invertido (haz &quot;luz roja&quot; en la Figura 1). La trampa óptica holográfica está construido alrededor de una nm láser DPSS 1064. El haz...

Atrapamiento óptico es una de las técnicas principales en la biofísica 6. Un avance crucial en la captura óptica ha sido el desarrollo de trampas holográficas que permiten la creación de patrones de trampas tridimensionales en lugar de trampas de punto convencionales 7. Tales trampas holográficas poseen la ventaja de la versatilidad en el posicionamiento de los objetos de refracción. Sin embargo trampas convencionales pueden ser fácilmente alineados a ser más simétrico que los kits holográficas disponibles comercialmente. También permiten rápido seguimiento preciso de los objetos atrapados. Aquí se describe un sistema (Figura 1) que combina los dos enfoques de captura en un solo instrumento y permite al usuario explotar los beneficios de ambos según sea apropiado. Las consideraciones generales de la construcción de trampas ópticas (basados ​​en rayos láser simples o múltiples) se discuten en detalle en otra parte 8-10. A continuación, resumimos los aspectos específicos de nuestro sETUP y proporcionar los detalles de nuestro proceso de alineación. Por ejemplo, los sistemas con dos haces ópticos de captura no se han descrito antes (por ejemplo, ref. 11), típicamente usando un haz de láser para atrapar un objeto de refracción y el uso de la otra (rayo de energía intencionalmente bajo) para la lectura desacoplado de la posición del objeto atrapado . Aquí, sin embargo, los dos haces de láser deben ser de alta potencia (300 mW o superior) debido a que ambos se van a utilizar para la captura. Para las mediciones de los sistemas biológicos, los láseres utilizados para la captura deberían caer de manera óptima dentro de una ventana de longitud de onda NIR específica para minimizar la degradación de la proteína inducida por la luz 1. Aquí se ha optado por utilizar el diodo 980 nm y 1064 nm láser DPSS debido a su bajo costo, alta disponibilidad y facilidad de operación. También hemos optado por utilizar un modulador espacial de luz (SLM) para crear y manipular múltiples trampas simultáneamente en 4,5 tiempo real. Estos dispositivos están disponibles comercialmentesin embargo, su integración en una instalación completa presenta desafíos únicos. Aquí se describe un enfoque práctico que aborda estas dificultades potenciales y proporciona un instrumento muy versátil. Se presenta un ejemplo explícito para la configuración específica descrita, que puede ser utilizado como una guía para los diseños modificados.

<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

Sistemas de microscopio de alta resolución con trampas ópticas permiten la manipulación precisa de los diversos objetos de refracción, tal como perlas de dieléctricos 1 u orgánulos celulares 2,3, así como para la lectura de alta resolución espacial y temporal de su posición con respecto al centro de la trampa. El sistema descrito en este documento tiene como &quot;tradicional&quot; trampa funciona a 980 nm. Es, además, proporciona un segundo sistema de captura óptica que utiliza un paquete holográfica disponibles comercialmente para crear y manipular simultáneamente patrones de trampas complejos en el campo de visión del microscopio 4,5 a una longitud de onda de 1064 nm. La combinación de los dos sistemas permite la manipulación de varios objetos de refracción al mismo tiempo, mientras que la realización simultánea mediciones de alta resolución de movimiento y la fuerza de producción a escala nanométrica y picoNewton alta velocidad y.

La configuración ensamblada permite al operador para atrapar varios objetos de refracción en tiempo real y la posición de ellos en todas las tres dimensiones dentro del campo de visión. Nos ilustran las capacidades holográficas del instrumento al atrapar 11 microesferas (Figura 2). La trampa de confinar cada objeto se volverá a colocar manualmente sobre la captura de manera que la disposición final muestra el logotipo de la Universidad de Utah, donde se llevó a cabo este experimento. Una funció...

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

El sistema descrito en este documento emplea una trampa óptica tradicional, así como una línea de trampas ópticas holográficas independiente, capaz de crear y manipular múltiples trampas. Esto permite la creación de disposiciones geométricas complejas de partículas de refracción a la vez que permite mediciones simultáneas de alta velocidad, de alta resolución de la actividad de enzimas biológicas.

Construcción de un microscopio de alta resolución con capacidades de captura óptica convencional y holográfica

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 vistas.  University of Utah. El sistema descrito en este documento emplea una trampa óptica tradicional, así como una línea de trampas ópticas holográficas independiente, capaz de crear y manipular múltiples trampas. Esto permite la creación de disposiciones geométricas complejas de partículas de refracción a la vez que permite mediciones simultáneas de alta velocidad, de alta resolución de la actividad de enzimas biológicas.

Video: 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.

De silicio policristalino película delgada de células solares con plasmónica mejorada luz que atrapa

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

Investigación

Ingeniería

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.

Construcción y verificación de las células de la moneda de baterías de ion de litio

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.

Trampas ópticas de las nanopartículas

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.

De alta resolución, de alta velocidad, tridimensional de imágenes de vídeo con técnicas de proyección digital de Fringe

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.

Convergentes Pulido: Una simple, rápida, completa Apertura Pulido Proceso de alta calidad óptica Pisos y Esferas

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.

Compacto holográfica microscopio digital Lente menos por MEMS Inspección y Caracterización

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.

Plasmónica la captura y liberación de nanopartículas en un entorno de monitorización

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.

Demostración de un microscopio integrado de Hyperlens y proyección de imagen de súper resolución

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.

Método para la grabación de espectros de emisiones de alta resolución de banda ancha de arcos relámpagos de laboratorio

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.

Solo dígito nanómetros litografía de haz de electrones con una aberración-corregido exploración microscopio electrónico de transmisión

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