26 research outputs found
Coherent anti-Stokes Raman Fourier ptychography
International audienceWe present a theoretical and numerical study of coherent anti-Stokes Raman scattering Fourier ptychography microscopy (CARS-FPM), a scheme that has not been considered so far in the previously reported CARS wide-field imaging schemes. In this approach, the distribution of the Raman scatterer density of the sample is reconstructed numerically from CARS images obtained under various angles of incidences of the pump or Stokes beam. Our inversion procedure is based on an accurate vectorial model linking the CARS image to the sample and yields both the real and imaginary parts of the susceptibility, the latter giving access to the Raman information, with an improved resolution
Metasurface optical characterization using quadriwave lateral shearing interferometry
An optical metasurface consists of a dense and usually non-uniform layer of
scattering nanostructures behaving as a continuous and extremely thin optical
component, with predefined phase and intensity transmission/reflection
profiles. To date, various sorts of metasurfaces (metallic, dielectric,
Huygens-like, Pancharatman-Berry, etc.) have been introduced to design
ultrathin lenses, beam deflectors, holograms, or polarizing interfaces. Their
actual efficiencies depend on the ability to predict their optical properties
and to fabricate non-uniform assemblies of billions of nanoscale structures on
macroscopic surfaces. To further help improve the design of metasurfaces,
precise and versatile post-characterization techniques need to be developed.
Today, most of the techniques used to characterize metasurfaces rely on light
intensity measurements. Here, we demonstrate how quadriwave lateral shearing
interferometry (QLSI), a quantitative phase microscopy technique, can easily
achieve full optical characterization of metasurfaces of any kind, as it can
probe the local phase imparted by a metasurface with high sensitivity and
spatial resolution. As a means to illustrate the versatility of this technique,
we present measurements on two types of metasurfaces, namely Pancharatnam-Berry
and effective-refractive-index metasurfaces, and present results on uniform
metasurfaces, metalenses and deflectors
Aberration-corrected large-scale hybrid metalenses
Hybrid components combining the optical power of a refractive and a diffractive optical system can form compact doublet lenses that correct various aberrations. Unfortunately, the diffraction efficiency of these devices decreases as a function of the deflection angle over the element aperture. Here, we address this issue, compensating for chromatic dispersion and correcting for monochromatic aberrations with centimeter-scale hybrid-metalenses. We demonstrate a correction of at least 80% for chromatic aberration and 70% for spherical aberration. We finally present monochromatic and achromatic images that clearly show how these hybrid systems outperform standard refractive lenses. The possibilities to adjust arbitrary spatial amplitude, phase, polarization, and dispersion profiles with hybrid metasurfaces offer unprecedented optical design opportunities for compact and broadband imaging, augmented reality/virtual reality, and holographic projection
Metasurface-enhanced Light Detection and Ranging Technology
Deploying advanced imaging solutions to robotic and autonomous systems by
mimicking human vision requires simultaneous acquisition of multiple fields of
views, named the peripheral and fovea regions. Low-resolution peripheral field
provides coarse scene exploration to direct the eye to focus to a highly
resolved fovea region for sharp imaging. Among 3D computer vision techniques,
Light Detection and Ranging (LiDAR) is currently considered at the industrial
level for robotic vision. LiDAR is an imaging technique that monitors pulses of
light at optical frequencies to sense the space and to recover
three-dimensional ranging information. Notwithstanding the efforts on LiDAR
integration and optimization, commercially available devices have slow frame
rate and low image resolution, notably limited by the performance of mechanical
or slow solid-state deflection systems. Metasurfaces (MS) are versatile optical
components that can distribute the optical power in desired regions of space.
Here, we report on an advanced LiDAR technology that uses ultrafast low FoV
deflectors cascaded with large area metasurfaces to achieve large FoV and
simultaneous peripheral and central imaging zones. This technology achieves MHz
frame rate for 2D imaging, and up to KHz for 3D imaging, with extremely large
FoV (up to 150{\deg}deg. on both vertical and horizontal scanning axes). The
use of this disruptive LiDAR technology with advanced learning algorithms
offers perspectives to improve further the perception capabilities and
decision-making process of autonomous vehicles and robotic systems.Comment: 25pages, 18 figures. Including supplementary material
Metasurface-enhanced light detection and ranging technology
: Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Among 3D computer vision techniques, LiDAR is currently considered at the industrial level for robotic vision. Notwithstanding the efforts on LiDAR integration and optimization, commercially available devices have slow frame rate and low resolution, notably limited by the performance of mechanical or solid-state deflection systems. Metasurfaces are versatile optical components that can distribute the optical power in desired regions of space. Here, we report on an advanced LiDAR technology that leverages from ultrafast low FoV deflectors cascaded with large area metasurfaces to achieve large FoV (150°) and high framerate (kHz) which can provide simultaneous peripheral and central imaging zones. The use of our disruptive LiDAR technology with advanced learning algorithms offers perspectives to improve perception and decision-making process of ADAS and robotic systems
Metasurface-enhanced light detection and ranging technology
Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Among 3D computer vision techniques, LiDAR is currently considered at the industrial level for robotic vision. Notwithstanding the efforts on LiDAR integration and optimization, commercially available devices have slow frame rate and low resolution, notably limited by the performance of mechanical or solid-state deflection systems. Metasurfaces are versatile optical components that can distribute the optical power in desired regions of space. Here, we report on an advanced LiDAR technology that leverages from ultrafast low FoV deflectors cascaded with large area metasurfaces to achieve large FoV (150°) and high framerate (kHz) which can provide simultaneous peripheral and central imaging zones. The use of our disruptive LiDAR technology with advanced learning algorithms offers perspectives to improve perception and decision-making process of ADAS and robotic systems
Effet du plasmon de surface localisé sur les propriétés des sources organiques (OLED)
L’utilisation de l’effet plasmonique de nanoparticules métalliques (NP) est l’une des voies les plus prometteuses pour améliorer les performances optiques et électriques des diodes électroluminescentes organiques (OLED). Le choix du métal, la taille et la position des NP sont liés aux propriétés physiques recherchées mais aussi aux approches et aux techniques permettant leur fabrication. Deux approches peuvent être utilisées : random metallic nanoparticules (RMN) et periodic metallic nanoparticules (PMN)
Effet du plasmon de surface localisé sur les propriétés des sources organiques (OLED)
L’utilisation de l’effet plasmonique de nanoparticules métalliques (NP) est l’une des voies les plus prometteuses pour améliorer les performances optiques et électriques des diodes électroluminescentes organiques (OLED). Le choix du métal, la taille et la position des NP sont liés aux propriétés physiques recherchées mais aussi aux approches et aux techniques permettant leur fabrication. Deux approches peuvent être utilisées : random metallic nanoparticules (RMN) et periodic metallic nanoparticules (PMN)
Quantitative model of the image of a radiating dipole through a microscope
International audienc
Space and Time Modulations of Light with Metasurfaces: Recent Progress and Future Prospects
International audienceIn this Perspective, we discuss the different opportunities offered by time-modulated metasurfaces for dynamic wavefront engineering and space-time photonics. Efforts in codesigning a photonic response while taking into careful consideration the switching/tuning mechanisms, including thermal, electronic, optical, chemical, and mechanical actuation, are essential for achieving sufficient amplitude, phase, and polarization modulation. Here, we examine in detail how the key enabling photonic technologies currently available and relying on similar tuning mechanisms can be applied for the conception of tunable metasurfaces. We review the latest developments and discuss the advantages and limitations of each approach, providing the reader with a clear vision of the current state of the art in active metasurfaces. We also address the readiness of each technological approach to drawing short- and long-term application perspectives. Finally, we discuss perspectives for spatiotemporal metasurface modulation opening new horizons toward unlimited wavefront engineering capabilities