The temperature distribution throughout arrays of illuminated metal nanoparticles is investigated numerically and experimentally. two cases continuous femtosecond-pulsed illumination are addressed. In the case illumination, distinct regimes evidenced: a confinement regime, where increase remains confined at vicinity each nanosource heat, delocalization uniform whole nanoparticle assembly despite heat sources' nanometric size. We show that occurrence one regime or another simply depends on...

We demonstrate stimulated Raman microscopy with broadband pump and Stokes pulses, using spectral focusing to attain resolution rapidly acquire spectra within a window determined by the bandwidth of pulses. As pulse, we use redshifted soliton generated in photonic crystal fiber, which allows for simple shifting accessible window.

We propose a three-color, double-modulation scheme for the background-free detection of stimulated Raman scattering (SRS). call gain and opposite loss (SRGOLD). It exploits symmetric nature potential parasitic signals (cross phase modulation, two-photon absorption, thermal effects) to end suppressing them. Conversely, antisymmetric SRS provides twofold increase in magnitude signal. experimentally demonstrate SRGOLD spectroscopy microscopy on test samples as well mice skin samples.

Optical metasurfaces have shown to be a powerful approach planar optical elements, enabling an unprecedented control over light phase and amplitude. At that stage, where wide variety of static functionalities been accomplished, most efforts are being directed toward achieving reconfigurable elements. Here, we present our electrically controlled varifocal metalens operating in the visible frequency range. It relies on dynamically controlling refractive index environment silicon by means...

In recent decades, optogenetics has been transforming neuroscience research, enabling neuroscientists to drive and read neural circuits. The development in illumination approaches combined with two-photon (2P) excitation, either sequential or parallel, opened the route for brain circuit manipulation single-cell resolution millisecond temporal precision. Yet, high excitation power required multi-target photostimulation, especially under 2P illumination, raises questions about induced local...

Coherent Raman scattering processes such as coherent anti-Stokes and stimulated are described in a tutorial way keeping simple physical pictures derivations. The simplicity of the presentation keeps however most key features these resonant their intimate relation with spontaneous scattering. This provides digest introduction to fundamental physics at work, it does not focus on numerous technological implementations; rather, concepts tools understand extensive literature this field. is made...

Performing label free coherent anti-Stokes Raman scattering (CARS) and stimulated (SRS) in endoscope imaging is a challenge, with huge potential clinical benefit. To date, this goal has remained inaccessible because of the inherent noise that generated fiber itself. By developing double-clad hollow core photonic crystal fiber, we demonstrate an 'endoscope-like' scheme. Both excitation beams collected CARS SRS signals travel through same fiber. No are within even for temporally overlapping...

Abstract Single‐particle electrochemistry at a nanoelectrode is explored by dark‐field optical microscopy. The analysis of the scattered light allows in situ dynamic monitoring electrodeposition single cobalt nanoparticles down to radius 65 nm. Larger sub‐micrometer particles are directly sized optically super‐localization edges and contains complementary information concerning particle redox chemistry. This opto‐electrochemical approach used derive mechanistic insights about...

ConspectusInterest in nanoparticles has vigorously increased over the last 20 years as more and studies show how their use can potentially revolutionize science technology. Their applications span many different academically industrially relevant fields such catalysis, materials science, health, etc. Until past decade, however, nanoparticle mostly relied on ensemble studies, thus leaving aside chemical heterogeneity at single particle level. Over few years, powerful new tools appeared to...

We developed a technique based on the use of smart patterns gold nanoparticles under illumination to generate any temperature field microscale.

We propose and implement a broadband, compact, low-cost wavefront sensing scheme by simply placing thin diffuser in the close vicinity of camera. The local gradient is determined from translation speckle pattern. vector map computed thanks to fast diffeomorphic image registration algorithm integrated reconstruct profile. simple grains under tip/tilt ensured so-called "memory effect" diffuser. Quantitative measurements are experimentally demonstrated, both for few first Zernike polynomials...

We report a simple add-on for broadband stimulated Raman scattering (SRS) microscopes to enable fast and programmable spectroscopy acquisition. It comprises conventional dispersive spectrometer layout incorporating digital micromirror device (DMD). The approach is validated by acquiring SRS spectra of standard chemicals. demonstrate DMD's advantage in showing higher signal-to-noise ratio using multiplexed Hadamard spectral basis compressive sensing detection. Our results apply variety...

Under illumination at their plasmonic resonance wavelength, metal nanoparticles can turn into efficient nanosources of heat by light absorption. Heating a small volume makes it possible to achieve fast dynamics. In this paper, we investigate theoretically, numerically, and experimentally the temperature distribution system generated modulated incoming light. particular, study response in amplitude phase variations. The cases single multiple are both addressed. Many parameters discussed such...

Aberrations and multiple scattering in biological tissues critically distort light beams into highly complex speckle patterns. In this regard, digital optical phase conjugation (DOPC) is a promising technique enabling in-depth focusing. However, DOPC becomes challenging when using fluorescent guide stars for four main reasons: the low photon budget available, large spectral bandwidth of signal, Stokes shift between emission excitation wavelength, absence reference beam preventing holographic...

Fluorescence microscopes can record the dynamics of living cells with high spatio-temporal resolution in a single plane. However, monitoring rapid and dim fluorescence fluctuations, e.g induced by neuronal activity brain, remains challenging for 3D-distributed emitters due to out-of-focus background, restricted photon budget, speed limit conventional scanning systems. Here, we introduce Thermally Adaptive Surface strategy, capable simultaneously recording, at camera framerate, objects. This...

<title>Abstract</title> Fluorescence microscopes can capture the dynamics of living cells with high spatio-temporal resolution in a single plane. However, monitoring rapid and dim fluorescence fluctuations, e.g. induced by neuronal activity brain, remains challenging for 3D-distributed emitters due to out-of-focus background, restricted photon budget, speed limit conventional scanning systems. Here, we introduce Thermally Adaptive Surface strategy, allowing parallel imaging objects at speeds...

By partially overcoming the diffraction limit, superlocalization techniques have extended applicability of optical down to nanometer size-range. Herein, cobalt oxide-based nanoparticles are electrochemically grown onto carbon nanoelectrodes and their individual catalytic properties evaluated through a combined electrochemical-optical approach. Using dark-field white light illumination, edges applied quantify changes in particle size during electrochemical activation with 20 nm precision. It...

Light propagation through scattering samples involves long optical path lengths typically resulting in short spectral correlation widths. Here, we demonstrate experimentally and theoretically a chromato-axial memory effect volumetric forward-scattering slabs of thickness lying the range between mean free transport path: shift impinging collimated beam results an axial homothetic dilation speckle pattern over large The center homothety is shown to lie at virtual plane located <mml:math...

We investigate how to extract information on the orientational order of molecular bonds in biological samples from polarized coherent anti-Stokes Raman scattering (CARS) and stimulated (SRS) microscopy. Experimentally, mean orientation angular distribution, as well its second fourth orders symmetry, are estimated by monitoring intensity signals under a varying incident polarization. provide generic method analysis both CARS SRS contrasts, apply it imaging lipid bonds' multilamellar vesicles....

Although extremely sensitive, electrical measurements are essentially unable to discriminate complex chemical events involving individual nanoparticles. The coupling of electrochemistry dark field imaging and spectroscopy allows the triggering electrodissolution an ensemble Ag nanoparticles (by electrochemistry) inference both oxidation dissolution processes spectroscopy) at level a single nanoparticle. Besides inspection process from optical scattering intensity, adding reveals changes...

Lighting is rapidly changing with the introduction of light-emitting diodes (LEDs) in our homes, workplaces, and cities. This evolution optical landscape raises major concerns regarding phototoxicity to retina since light exposure an identified risk factor for development age-related macular degeneration (AMD). In this disease, cone photoreceptors degenerate while retinal pigment epithelium (RPE) accumulating lipofuscin containing phototoxic compounds such as A2E. Therefore, it remains...

We report on an optical microscopy technique aimed at measuring the absolute absorption cross section of individual nanoparticles. It relies thermally induced variation refractive index surrounding medium subsequent to light by nanoparticle. The is illustrated gold nanoparticles featuring a well-defined plasmonic resonance. Different modes were evidenced and quantified. simplicity rapidity measurements make it possible investigate resonances absorbing nanostructures microstructures in...