The financial support by DFG (German research foundation, project CZ 55/30-1) for parts of this work is gratefully acknowledged.

1. Montaggio del setup sperimentale <ol><li> Preparazione della parte prossimale <ol><li> Posizionare e fissare il laser che emette un fascio di luce collimato - o utilizzare un laser accoppiato in fibra ottica con collimazione alla sfaccettatura all&#39;uscita della fibra. </li><li> Mettere il divisore di fascio polarizzante (PBS) per dividere il raggio laser in riferimento e fascio oggetto. Ruotare l&#39;orientamento delle piastre semionda (HWP) ruotando il HWP nella sua rotazione montare finché l&#39;alimentazione del fascio di riferimento e fascio oggetto (sul lato distale) è circa la stessa. Controllare questo mettendo uno schermo in entrambi riferimento e fascio oggetto. Scegliere l&#39;orientamento della PBS in modo che la polarizzazione del fascio di riferimento si inserisce il modulatore spaziale di luce polarizzazione-sensitive (SLM). </li><li> Mettere un divisore di fascio (BS) nel fascio di riferimento per dividere il fascio di riferimento in due fasci. Posizionare i modulatori ottici (OM) tali che questi due fasci provenienti da BS1 possono passare OM1 e OM2, rispettivamente. &lt;/ Li&gt; <li> Unire i due fasci di passaggio OM1 e OM2 a BS2 impiegando due specchi. Regolare i separatori di fasci e specchi in modo che entrambi i fasci sono spazialmente separate. </li><li> allineare attentamente BS5 per assicurare che la direzione di incidenza di entrambi i fasci è perpendicolare al piano pixel del SLM, BS3 ignorando e BS4 all&#39;inizio. In un primo momento, non viene visualizzato sul SLM, cioè, agisce come uno specchio fino al termine della taratura (durante il passaggio 2). </li><li> Regolare la posizione e la distanza tra le due lenti (L) costituente un telescopio kepleriano per ottenere un&#39;immagine nitida del piano SLM sulla telecamera Complementary Metal-Oxide Semiconductor (CMOS). Osservare il corretto orientamento di L1 e L2 (facce piane di fronte all&#39;altra) per minimizzare le aberrazioni. </li></ol></li><li> Preparazione della parte distale <ol><li> Utilizzare BS7 per dividere il fascio oggetto in due fasci e combinarle a BS8 impiegando due specchi. Anche in questo caso, regolare i separatori di fasci e mirrors modo che entrambi i fasci sono spazialmente separate. </li><li> Deviare entrambe le travi utilizzando BS9 loro mirare all&#39;obiettivo del microscopio (OBJ). Fuoco OBJ2 sull&#39;estremità distale della fibra multimodale (MMF). Controllare la messa a fuoco osservando il riflesso indietro dal MMF impiegando L3 e un dispositivo di fotocamera ad accoppiamento di carica (CCD). </li></ol></li><li> Prossimale Collegamento e parte distale <ol><li> Collimare la luce dal fascio oggetto uscita dal MMF impiegando OBJ1. </li><li> Dividere il fascio oggetto utilizzando BS6, ignorare il polarizzatore lineare (LP) in un primo momento. Combinare entrambi i fasci di oggetto con entrambi i fasci di riferimento a BS3 e BS4 impiegano uno specchio. Regolare i divisori di fascio e specchi in modo che ciascuna coppia di riferimento e la sovrapposizione fascio oggetto allo SLM, intersecante con un piccolo angolo (meno di 1 °). </li><li> Assicurarsi che la potenza di riferimento e la trave oggetto sono all&#39;incirca uguali ruotando l&#39;orientamento del HWP, secondo la fase 1.1.2. </li><li> Controllare l&#39;interferenza pattern (fuori asse ologramma) alla telecamera CMOS e regolare l&#39;angolo di intersezione di conseguenza. Aumentare l&#39;angolo, fino a quando la distanza interferenza frangia è uguale o meno le dimensioni di due pixel della fotocamera CMOS. </li><li> Regolare l&#39;orientamento del LP per abbinare la polarizzazione del fascio di riferimento dell&#39;oggetto e per ottenere un contrasto massimo della figura di interferenza immagine della telecamera CMOS, in modo che l&#39;immagine della telecamera mostra frange distinti. </li></ol></li></ol> 2. Calibrazione del sistema <ol><li> Calibrazione della relazione pixel tra SLM e CMOS <ol><li> Illuminare tutta SLM utilizzando solo uno dei fasci di riferimento e bloccare l&#39;altro riferimento e oggetti travi. </li><li> Acquisire un&#39;immagine SLM con la fotocamera CMOS. </li><li> Ottenere le coordinate dell&#39;angolo superiore sinistro della SLM immagine della telecamera CMOS, ad esempio, utilizzando software di grafica e il cursore del mouse sul PC. Utilizzare queste coordinate pixel come il punto di origineper quanto riguarda l&#39;SLM. </li><li> Rimuovere tutti i blocchi del fascio. </li></ol></li><li> Calibrazione dei percorsi di segnale <ol><li> Bloccare entrambi riferimento fascio 2 e l&#39;oggetto del fascio 2. </li><li> Acquisire un&#39;immagine dell&#39;ologramma con la fotocamera CMOS. Valutare la fase nell&#39;ologramma registrati utilizzando il metodo dello spettro angolare 19. Calcolare la fase invertita nella regione corrispondente trave 1. </li><li> Rimuovere i blocchi ex fascio e ora bloccare sia di riferimento trave 1 e oggetto trave 1. </li><li> Acquisire un&#39;immagine dell&#39;ologramma con la fotocamera CMOS. Misurare la fase nell&#39;ologramma registrato con nuovo metodo spettro angolare. Calcolare la fase invertita al corrispondente regione del fascio 2. </li><li> Rimuovere tutti i blocchi del fascio. </li></ol></li></ol> 3. trasmettere i segnali <ol><li> Bloccare il fascio oggetto. </li><li> Unire le immagini di fase invertite calcolati ai corrispondenti regioni del fascio 1 e 2 insieme e visualizzare ilintera immagine sullo SLM, tipicamente utilizzando la porta grafica computerizzata. </li><li> Avviare la modulazione dei segnali di ingresso 1 e 2 attivando OM1 e OM2. </li><li> Osservare i segnali di uscita 1 e 2 sulla fotocamera CCD. </li></ol>

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<li>Lee, K., Lee, J., Park, J. H., Park, J. H., Park, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((One-wave+optical+phase+conjugation+mirror+by+actively+coupling+arbitrary+light+fields+into+a+single-mode+reflector%5BTitle%5D)+AND+%22Phys.+Rev.+Lett%22%5BJournal%5D)">One-wave optical phase conjugation mirror by actively coupling arbitrary light fields into a single-mode reflector.</a> Phys. Rev. Lett. 115 (15), 153902(2015).</li>
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</ol>

The authors have nothing to disclose.

Il montaggio del setup sperimentale (passaggio 1 nel protocollo) richiede un allineamento accurato dei componenti ottici rispetto all&#39;altro. L&#39;aspetto più importante è l&#39;incidenza rettangolare delle travi di riferimento e la SLM, al fine di garantire un elevato PBR. Al fine di migliorare la configurazione a più di due segnali trasmessi, separatori di fasci aggiuntivi potrebbero essere utilizzati. In alternativa, una implementazione a base di fibre sarebbe più compatta e robus...

La trasmissione di più segnali di luce attraverso una fibra multimodale (MMF) è evidente nelle comunicazioni di ingegneria 1 e 2 biofotonica. In Ingegneria delle telecomunicazioni, spazio-division multiplexing (SDM) si crede di essere una soluzione praticabile al fine di migliorare la capacità di trasmissione delle fibre ottiche per le future applicazioni di trasferimento dati che beneficiano di un maggiore utilizzo dello spazio limitato, rispetto a più fibre monomodali 3. In biofotonica, campioni biologici sono manipolati trasmettendo la luce attraverso un endoscopio MMF 4. Ad esempio, il controllo ottico indipendente dei singoli neuroni utilizzando endoscopi MMF è di interesse per optogenetics per studiare reti neuronali nel cervello 5. Tuttavia, la luce proiettata sulla sfaccettatura di ingresso MMF è soggetto a distorsione dovuta alla modalità di miscelazione e dispersione durante la propagazione al output aspetto del MMF. Come risultato, la propagazione della luce viene alterata, che rende difficile la trasmissione del segnale. Wavefront metodi di formatura 6, 7 sono applicati in dispersione media utilizzando modulatori spaziali di luce (SLM) e consentire la compensazione per la distorsione a causa di dispersione durante la propagazione della luce 8. Ci sono approcci iterativi che ottimizzano l&#39;uscita utilizzando un feedback ottico 9. Questi approcci sono piuttosto tempo a causa della necessità per numerose iterazioni e l&#39;alto grado di libertà, corrispondente ad un gran numero di elementi modulatori. Un altro approccio è quello di determinare completamente i distorsione ai MMF descritto dal suo matrice di trasmissione 10. Se il numero di modalità da trasmettere è grande, questo sarà tempo pure. In contrasto, digitale coniugazione di fase ottica (DOPC) è consideratoveloce e vantaggioso qui, dal momento che solo pochi punti focali devono essere generata nel sfaccettatura uscita del MMF. Approcci coniugazione di fase sono stati dimostrati per focalizzare o immagini attraverso tessuto biologico 12, 13, 14. Finora, DOPC stato impiegato per un singolo segnale volta solo 15, 16, ed è stato applicato per la trasmissione della luce attraverso un MMF 17. Un approccio DOPC per molteplici segnali indipendenti non è stato realizzato. Abbiamo sviluppato un metodo DOPC migliorata fornendo la trasmissione indipendente di più segnali luminosi utilizzando wavefront individuale sagomatura per ciascun segnale impiegando un singolo di sola fase SLM 18. A questo scopo, il SLM è segmentata in regioni, uno per ogni segnale da trasmettere. L&#39;apparato sperimentale proposto è mostrata in figura 1, Dove una calibrazione viene eseguita in a) prima della trasmissione effettiva accade in b). <img alt="Figura 1" src="/files/ftp_upload/55407/55407fig1.jpg" /> Figura 1: configurazione sperimentale. BS = divisore di fascio, CCD = dispositivo ad accoppiamento di carica, OM = modulatore ottico, CMOS = Complementary Metal-Oxide Semiconductor, HWP = metà piatto dell&#39;onda, L = lente, LP = polarizzatore lineare, MMF = fibra multimodale, obiettivo OBJ = microscopio, PBS = polarizzazione divisore di fascio, SLM = modulatore spaziale di luce (fase unica) - solo travi rilevanti per (a) la calibrazione e (b) la trasmissione sono raffigurati <a href="http://ecsource.jove.com/files/ftp_upload/55407/55407fig1large.jpg" target="_blank">cliccate qui per vedere una versione più grande di questa figura.</a>

<table><tbody><tr><td>spatial light modulator</td><td>Holoeye</td><td>PLUTO-VIS-016</td><td></td></tr><tr><td>CMOS camera</td><td>Mikrotron</td><td>MC4082</td><td></td></tr><tr><td>diode-pumped solid state laser</td><td>Laser Quantum</td><td>torus 532</td><td></td></tr><tr><td>CCD camera</td><td>IDS</td><td>U3-3482LE-M CMOS</td><td>camera; suitable as well</td></tr><tr><td>lens 1</td><td>Qioptiq</td><td>G063204000</td><td></td></tr><tr><td>lens 2</td><td>Qioptiq</td><td>G063203000</td><td></td></tr><tr><td>lens 3</td><td>Thorlabs</td><td>AC508-180-A-ML</td><td></td></tr><tr><td>multimode fiber</td><td>Thorlabs</td><td>M14L02</td><td></td></tr><tr><td>beam splitters</td><td>Thorlabs</td><td>BS013</td><td>9x</td></tr><tr><td>polarizing beam splitters</td><td>Thorlabs</td><td>PBS251</td><td></td></tr><tr><td>mirrors</td><td>Thorlabs</td><td>PF10-03-P01</td><td>5x</td></tr><tr><td>microscope objectives</td><td>Thorlabs</td><td>RMS20X</td><td>2x</td></tr><tr><td>half wave plates</td><td>Thorlabs</td><td>WPH10M-532</td><td>2x</td></tr><tr><td>linear polarizer</td><td>Thorlabs</td><td>LPVISB050-MP2</td><td></td></tr><tr><td>optical modulators</td><td>Thorlabs</td><td>MC2000B-EC</td><td>2x</td></tr><tr><td>linear and rotation stage for CMOS camera</td><td>Thorlabs</td><td>XYR1/M</td><td></td></tr><tr><td>fiber connector</td><td>Thorlabs</td><td>S120-SMA</td><td>2x</td></tr><tr><td>reducing ring for microscope objectives</td><td>Qioptiq</td><td>G061621000</td><td>2x</td></tr><tr><td>xy adjustment for objective adapters</td><td>Qioptiq</td><td>G061025000</td><td>2x</td></tr><tr><td>z translation mount for fiber adapter</td><td>Thorlabs</td><td>SM1Z</td><td>2x</td></tr><tr><td>rods for fiber alignment to objectives</td><td>Qioptiq</td><td>G061210000</td><td>8x</td></tr><tr><td>mounts for lenses 1 and 2 plus two phantom mounts</td><td>Qioptiq</td><td>G061047000</td><td>4x</td></tr><tr><td>rail carriers for objective and lens mounts</td><td>Qioptiq</td><td>G061372000</td><td>6x</td></tr><tr><td>rail for rail carriers</td><td>Qioptiq</td><td>G061359000</td><td>2x</td></tr><tr><td>adapter for CCD camera to 1 post</td><td></td><td></td><td>in-house</td></tr><tr><td>adapter for laser to 4 posts</td><td></td><td></td><td>in-house</td></tr><tr><td>mount for lens 3</td><td>Thorlabs</td><td>LMR2/M</td><td></td></tr><tr><td>mounts for half wave plates</td><td>Thorlabs</td><td>RSP1D/M</td><td>2</td></tr><tr><td>mounts for mirrors</td><td>Thorlabs</td><td>KM100</td><td>5x</td></tr><tr><td>mount for linear polarizer</td><td>Thorlabs</td><td>RSP05/M</td><td></td></tr><tr><td>mounts for beam splitters and SLM</td><td>Thorlabs</td><td>KM100PM/M</td><td>11x</td></tr><tr><td>clamping arms for beam splitters and SLM</td><td>Thorlabs</td><td>PM4/M</td><td>11x</td></tr><tr><td>posts for mounts, rail carriers and adapters</td><td>Thorlabs</td><td>TR75/M</td><td>29x</td></tr><tr><td>holders for posts</td><td>Thorlabs</td><td>PH50/M</td><td>29x</td></tr><tr><td>pedestals for holders</td><td>Thorlabs</td><td>BE1/M</td><td>29x</td></tr><tr><td>clamping forks for pedestals</td><td>Thorlabs</td><td>CF125</td><td>29x</td></tr></tbody></table>

transmission of multiple signals through an optical fiber using wavefront shaping

La trasmissione di più segnali ottici indipendenti attraverso una fibra multimodale viene eseguita mediante formatura fronte d&#39;onda al fine di compensare la distorsione della luce durante la propagazione all&#39;interno della fibra. La nostra metodologia si basa su digitale coniugazione di fase ottica utilizzando solo un singolo modulatore spaziale di luce, in cui il fronte d&#39;onda ottica è modulata individualmente in diverse regioni del modulatore, una regione al segnale luminoso. approcci coniugazione di fase ottica digitali sono considerati più veloce di altri wavefront modellatura approcci, dove (per esempio) viene eseguita una determinazione completa del comportamento di propagazione dell&#39;onda della fibra. Al contrario, il metodo presentato è tempo efficiente poiché richiede soltanto una calibrazione per ogni segnale luminoso. Il metodo proposto è potenzialmente appropriato per spaziale multiplexing divisione in Ingegneria delle telecomunicazioni. Ulteriori campi di applicazione sono la consegna luce endoscopica in biofotonica, in particolare in optogenetics, dove le cellule singole in tessuto biologico devono essere selettivamente illuminati con alta risoluzione spaziale e temporale.

<html> Segnali di uscita Tipici a lato distale della fibra 2 m di lunghezza sono descritte nella Figura 2. Si noti che il punto focale desiderata (picco) è accompagnato da un speckle indesiderato (background), che è dovuto all&#39;imperfezione della DOPC come questione di principio. Il corrispondente rapporto picco-a-fondo (PBR) è pari a 53 (solo il segnale 1 è &#39;on&#39;), 36 (solo segnale 2 è &#39;on&#39;) e 20 (entrambi i segnali 1 e 2 sono &#39;on&#39;) qui, ri...

Watch this Scientific Journal Video about Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping at JoVE.com

Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping

We demonstrate the transmission of multiple independent signals through a multimode fiber using wavefront shaping employing a single spatial light modulator. By modulating the wavefront for each signal individually, spatially separated foci are transmitted. Potential applications are multiplexed data transfer in communications engineering and endoscopic light delivery in biophotonics.

La trasmissione di segnali multipli attraverso una fibra ottica Utilizzando Wavefront Shaping

The transmission of multiple independent optical signals through a multimode fiber is accomplished using wavefront shaping in order to compensate for the ...

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9.8K Views.  TU Dresden. We demonstrate the transmission of multiple independent signals through a multimode fiber using wavefront shaping employing a single spatial light modulator. By modulating the wavefront for each signal individually, spatially separated foci are transmitted. Potential applications are multiplexed data transfer in communications engineering and endoscopic light delivery in biophotonics.

Video: Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping

Microwave Photonics Systems Based on Whispering-gallery-mode Resonators

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various areas of technology and applied science, such as aerospace and communication engineering, sensing, metrology, nonlinear photonics, and quantum optics. In this article, we present the principal techniques used in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators. First detailed in this article is the protocol for resonator polishing, which is based on a grind-and-polish technique close to the ones used to polish optical components such as lenses or telescope mirrors. Then, a white light interferometric profilometer measures surface roughness, which is a key parameter to characterize the quality of the polishing. In order to launch light in the resonator, a tapered silica fiber with diameter in the micrometer range is used. To reach such small diameters, we adopt the "flame-brushing" technique, using simultaneously computer-controlled motors to pull the fiber apart, and a blowtorch to heat the fiber area to be tapered. The resonator and the tapered fiber are later approached to one another to visualize the resonance signal of the whispering gallery modes using a wavelength-scanning laser. By increasing the optical power in the resonator, nonlinear phenomena are triggered until the formation of a Kerr optical frequency comb is observed with a spectrum made of equidistant spectral lines. These Kerr comb spectra have exceptional characteristics that are suitable for several applications in science and technology. We consider the application related to ultra-stable microwave frequency synthesis and demonstrate the generation of a Kerr comb with GHz intermodal frequency.

The customized techniques developed in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators are presented. The protocols to obtain and characterize these resonators are detailed, and an explanation of some of their applications in microwave photonics is given.

Microonde Photonics sistemi basati su risonatori-galleria-mode Whispering

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various ...

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Ingegneria

Quasi-light Storage for Optical Data Packets

Today's telecommunication is based on optical packets which transmit the information in optical fiber networks around the world. Currently, the processing of the signals is done in the electrical domain. Direct storage in the optical domain would avoid the transfer of the packets to the electrical and back to the optical domain in every network node and, therefore, increase the speed and possibly reduce the energy consumption of telecommunications. However, light consists of photons which propagate with the speed of light in vacuum. Thus, the storage of light is a big challenge. There exist some methods to slow down the speed of the light, or to store it in excitations of a medium. However, these methods cannot be used for the storage of optical data packets used in telecommunications networks. Here we show how the time-frequency-coherence, which holds for every signal and therefore for optical packets as well, can be exploited to build an optical memory. We will review the background and show in detail and through examples, how a frequency comb can be used for the copying of an optical packet which enters the memory. One of these time domain copies is then extracted from the memory by a time domain switch. We will show this method for intensity as well as for phase modulated signals.

The article describes a procedure to store optical data packets with an arbitrary modulation, wavelength, and data rate. These packets are the basis of modern telecommunications.

Stoccaggio Quasi-luce per ottiche pacchetti di dati

Today's telecommunication is based on optical packets which transmit the information in optical fiber networks around the world. Currently, the processing ...

Fabrication and Characterization of Disordered Polymer Optical Fibers for Transverse Anderson Localization of Light

We develop and characterize a disordered polymer optical fiber that uses transverse Anderson localization as a novel waveguiding mechanism. The developed polymer optical fiber is composed of 80,000 strands of poly (methyl methacrylate) (PMMA) and polystyrene (PS) that are randomly mixed and drawn into a square cross section optical fiber with a side width of 250 &mu;m. Initially, each strand is 200 &mu;m in diameter and 8-inches long. During the mixing process of the original fiber strands, the fibers cross over each other; however, a large draw ratio guarantees that the refractive index profile is invariant along the length of the fiber for several tens of centimeters. The large refractive index difference of 0.1 between the disordered sites results in a small localized beam radius that is comparable to the beam radius of conventional optical fibers. The input light is launched from a standard single mode optical fiber using the butt-coupling method and the near-field output beam from the disordered fiber is imaged using a 40X objective and a CCD camera. The output beam diameter agrees well with the expected results from the numerical simulations. The disordered optical fiber presented in this work is the first device-level implementation of 2D Anderson localization, and can potentially be used for image transport and short-haul optical communication systems.

We develop and characterize a disordered polymer optical fiber that uses transverse Anderson localization as a novel waveguiding mechanism. This microstructured fiber can transport a small localized beam with a radius that is comparable to the beam radius of conventional optical fibers.

Fabbricazione e caratterizzazione di polimeri disordinati fibre ottiche per la Trasversale localizzazione di Anderson di Luce

We develop and characterize a disordered polymer optical fiber that uses transverse Anderson localization as a novel waveguiding mechanism. The developed ...

Writing Bragg Gratings in Multicore Fibers

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong suppression at a single wavelength requires that all cores have matching transmission profiles. These gratings cannot be inscribed using the same method as for single-core fibers because the curved surface of the cladding acts as a lens, focusing the incoming UV laser beam and causing variations in exposure between cores. Therefore we use an additional optical element to ensure that the beam shape does not change while passing through the cross-section of the multicore fiber. This consists of a glass capillary tube which has been polished flat on one side, which is then placed over the section of the fiber to be inscribed. The laser beam enters the fiber through the flat surface of the capillary tube and hence maintains its original dimensions. This paper demonstrates the improvements in core-to-core uniformity for a 7-core fiber using this method. The technique can be generalized to larger multicore fibers.

We describe a technique for inscribing identical fiber Bragg gratings into each core of a multicore fiber. This is achieved by introducing an additional surface into the optical path to mitigate lensing by the curved surface of the fiber cladding.

Scrivendo di Bragg in fibra Multicore

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong ...

High-Throughput Total Internal Reflection Fluorescence and Direct Stochastic Optical Reconstruction Microscopy Using a Photonic Chip

Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced contrast due to optical sectioning. The conventional approach is to use high numerical aperture microscope TIRF objectives for both excitation and collection, severely limiting the field of view and throughput. We present a novel approach to generating TIRF excitation for imaging with optical waveguides, called chip-based nanoscopy. The aim of this protocol is to demonstrate how chip-based imaging is performed in an already built setup. The main advantage of chip-based nanoscopy is that the excitation and collection pathways are decoupled. Imaging can then be done with a low magnification lens, resulting in large field of view TIRF images, at the price of a small reduction in resolution. Liver sinusoidal endothelial cells (LSECs) were imaged using direct stochastic optical reconstruction microscopy (dSTORM), showing a resolution comparable to traditional super-resolution microscopes. In addition, we demonstrate the high-throughput capabilities by imaging a 500 &#181;m x 500 &#181;m region with a low magnification lens, providing a resolution of 76 nm. Through its compact character, chip-based imaging can be retrofitted into most common microscopes and can be combined with other on-chip optical techniques, such as on-chip sensing, spectroscopy, optical trapping, etc. The technique is thus ideally suited for high throughput 2D super-resolution imaging, but also offers great opportunities for multi-modal analysis.

Chip-based super-resolution optical microscopy is a novel approach to fluorescence microscopy and offers advantages in cost effectiveness and throughput. Here, the protocols for chip preparation and imaging are shown for TIRF microscopy and localization-based super-resolution microscopy.

Fluorescenza della riflessione interna totale ad alto consumo e microscopia della ricostruzione ottica stocastica diretta utilizzando un chip fotonico

Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced ...

Biochimica

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

The aim of this article is to visually demonstrate the utilization of an interferometric method for encoding complex fields associated with coherent laser radiation. The method is based on the coherent sum of two uniform waves, previously encoded into a phase-only spatial light modulator (SLM) by spatial multiplexing of their phases. Here, the interference process is carried out by spatial filtering of light frequencies at the Fourier plane of certain imaging system. The correct implementation of this method allows arbitrary phase and amplitude information to be retrieved at the output of the optical system.
It is an on-axis, rather than off-axis encoding technique, with a direct processing algorithm (not an iterative loop), and free from coherent noise (speckle). The complex field can be exactly retrieved at the output of the optical system, except for some loss of resolution due to the frequency filtering process. The main limitation of the method might come from the inability to operate at frequency rates higher than the refresh rate of the SLM. Applications include, but are not limited to, linear and non-linear microscopy, beam shaping, or laser micro-processing of material surfaces.

We show how to encode the complex field of laser beams by using a single phase element. A common-path interferometer is employed to mix the phase information displayed into a phase-only spatial light modulator to finally retrieve the desired complex field pattern at the output of an optical imaging system.

Modellare l'ampiezza e la fase dei fasci Laser utilizzando un modulatore di luce spaziale sola fase

The aim of this article is to visually demonstrate the utilization of an interferometric method for encoding complex fields associated with coherent laser ...

Low-cost Custom Fabrication and Mode-locked Operation of an All-normal-dispersion Femtosecond Fiber Laser for Multiphoton Microscopy

A protocol is presented to build a custom low-cost yet high-performance femtosecond (fs) fiber laser. This all-normal-dispersion (ANDi) ytterbium-doped fiber laser is built completely using commercially available parts, including $8,000 in fiber optic and pump laser components, plus $4,800 in standard optical components and extra-cavity accessories. Researchers new to fiber optic device fabrication may also consider investing in basic fiber splicing and laser pulse characterization equipment (~$63,000). Important for optimal laser operation, methods to verify true versus apparent (partial or noise-like) mode-locked performance are presented. This system achieves 70 fs pulse duration with a center wavelength of approximately 1,070 nm and a pulse repetition rate of 31 MHz. This fiber laser exhibits the peak performance that may be obtained for an easily assembled fiber laser system, which makes this design ideal for research laboratories aiming to develop compact and portable fs laser technologies that enable new implementations of clinical multiphoton microscopy and fs surgery.

A method is presented to build a custom low-cost, mode-locked femtosecond fiber laser for potential applications in multiphoton microscopy, endoscopy, and photomedicine. This laser is built using commercially available parts and basic splicing techniques.

Fabbricazione personalizzata a basso costo e funzionamento bloccato in modalità di un laser in fibra Femtosecond a dispersione all'innormale per la microscopia multifotone

A protocol is presented to build a custom low-cost yet high-performance femtosecond (fs) fiber laser. This all-normal-dispersion (ANDi) ytterbium-doped ...

Characterization of SiN Integrated Optical Phased Arrays on a Wafer-Scale Test Station

Optical phased arrays (OPAs) can produce low-divergence laser beams and can be used to control the emission angle electronically without the need for moving mechanical parts. This technology is particularly useful for beam steering applications. Here, we focus on OPAs integrated into SiN photonic circuits for a wavelength in the near infrared. A characterization method of such circuits is presented, which allows the output beam of integrated OPAs to be shaped and steered. Furthermore, using a wafer-scale characterization setup, several devices can easily be tested across multiple dies on a wafer. In this way, fabrication variations can be studied, and high-performance devices identified. Typical images of OPA beams are shown, including beams emitted from OPAs with and without a uniform waveguide length, and with varying numbers of channels. In addition, the evolution of output beams during the phase optimization process and beam steering in two dimensions is presented. Finally, a study of the variation in the beam divergence of identical devices is performed with respect to their position on the wafer.

Here, we describe the operation of a SiN integrated photonic circuit containing optical phased arrays. The circuits are used to emit low divergence laser beams in the near infrared and steer them in two dimensions.

Caratterizzazione degli array ottici integrati sin sin su una stazione di test su scala Wafer

Optical phased arrays (OPAs) can produce low-divergence laser beams and can be used to control the emission angle electronically without the need for ...

Multicolor Fluorescence Detection for Droplet Microfluidics Using Optical Fibers

Fluorescence assays are the most common readouts used in droplet microfluidics due to their bright signals and fast time response. Applications such as multiplex assays, enzyme evolution, and molecular biology enhanced cell sorting require the detection of two or more colors of fluorescence. Standard multicolor detection systems that couple free space lasers to epifluorescence microscopes are bulky, expensive, and difficult to maintain. In this paper, we describe a scheme to perform multicolor detection by exciting discrete regions of a microfluidic channel with lasers coupled to optical fibers. Emitted light is collected by an optical fiber coupled to a single photodetector. Because the excitation occurs at different spatial locations, the identity of emitted light can be encoded as a temporal shift, eliminating the need for more complicated light filtering schemes. The system has been used to detect droplet populations containing four unique combinations of dyes and to detect sub-nanomolar concentrations of fluorescein.

Multicolor fluorescence detection in droplet microfluidics typically involves bulky and complex epifluorescence microscope-based detection systems. Here we describe a compact and modular multicolor detection scheme that utilizes an array of optical fibers to temporally encode multicolor data collected by a single photodetector.

Multicolore fluorescenza Detection per Droplet microfluidica tramite fibre ottiche

Fluorescence assays are the most common readouts used in droplet microfluidics due to their bright signals and fast time response. Applications such as ...

Bioingegneria

Optimizing Brillouin Optical Time-Domain Analyzers Based on Gain Spectrum Engineering

Demonstrated is a unique method for sensing performance enhancement in Brillouin optical time-domain analyzers (BOTDA). A Brillouin gain spectrum (BGS) is superimposed with two symmetric Brillouin loss spectra (BLS). This leads to a complex engineered spectrum shape that is more resistant to the sensing system noise. Instead of only one pump and probe interaction as in the conventional BOTDA setup, three optical probe waves are exploited, with one probe located in the BGS and the other two symmetrically in the BLS. Due to the resistance and insensitivity of the engineered spectrum shape to the noise, the sensing performance is enhanced by 60% and the measurand resolution is doubled.

<meta charset="utf8"></head><body>Ottimizzazione degli analizzatori ottici nel dominio del tempo Brillouin basati sull'ingegneria dello spettro del guadagno

A protocol for Brillouin optical time-domain analyzers based on gain spectrum engineering is presented. Enhancements in the sensing performance, including sensing range and measurand resolution are achieved and the excess Brillouin intensity noise is studied. The protocol introduces a new way to enhance distributed Brillouin sensing performance.

Ottimizzazione degli analizzatori ottici nel dominio del tempo Brillouin basati sull'ingegneria dello spettro del guadagno

Demonstrated is a unique method for sensing performance enhancement in Brillouin optical time-domain analyzers (BOTDA). A Brillouin gain spectrum (BGS) is ...