Étude en champ proche optique de cristaux photoniques bidimensionnels sur membrane suspendue

Nous presentons une etude experimentale en champ proche optique d'un cristal photonique 2D inscrit dans une membrane suspendue photoluminescente emettant a 1.5 μm. Les images obtenues mettent en evidence le guidage de la PL par la membrane, l'effet de bande interdite photonique ainsi que l'inhibition de l'emission de PL a l'interieur du cristal photonique.

Near-field probing of active photonic-crystal structures

We report a study of the optical near field of an active integrated component operating near the 1.55-mum telecommunications wavelength. The device is based on a two-dimensional photonic crystal etched in a suspended InP membrane. Topographic as well as optical information is collected by use of a scanning near-field optical microscope in collection mode, providing information about the local distribution of the losses.

Photovoltaics: Photonic Crystal-Driven Spectral Concentration for Upconversion Photovoltaics (Advanced Optical Materials 4/2015)

Real space observation of two-dimensional Bloch wave interferences in a negative index photonic crystal cavity

We report here the direct observation of two-dimensional (2D) Bloch wave interferences in a negative index photonic crystal by using optical near-field microscopy techniques. The photonic crystal is formed by a defectless honeycomb lattice of air holes etched in III-V semiconductor slab. A scanning near-field optical microscope is used to visualize spatially, as well as spectrally, the light distribution inside the photonic crystal. The recorded near-field spectra and maps presented here unambiguously demonstrate the Bloch wave interferences within the photonic crystal. Then, the spectral and spatial evolution of these interferences allows us to recover experimentally the 2D band diagram of…

Photonic Crystal‐Driven Spectral Concentration for Upconversion Photovoltaics

The main challenge for applying upconversion (UC) to silicon photovoltaics is the limited amount of solar energy harvested directly via erbium-based upconverter materials (24.5 W m–2). This could be increased up to 87.7 W m–2 via spectral concentration. Due to the nonlinear behavior of UC, this could increase the best UC emission by a factor 13. In this paper, the combined use of quantum dots (QDs)—for luminescent down-shifting—and photonic crystals (PCs)—for reshaping the emission—to achieve spectral concentration is shown. This implies dealing with the coupling of colloidal QDs and PC at the high-density regime, where the modes are shifted and broadened. In the first fabricated all-optica…

Near-field observation of subwavelength confinement of photoluminescence by a photonic crystal microcavity

We present a direct, room-temperature near-field optical study of light confinement by a subwavelength defect microcavity in a photonic crystal slab containing quantum-well sources. The observations are compared with three-dimensional finite-difference time-domain calculations, and excellent agreement is found. Moreover, we use a subwavelength cavity to study the influence of a near-field probe on the imaging of localized optical modes. © 2006 Optical Society of America.

Absorption enhancement in monocrystalline Si thin films using pseudodisordered structures

21-25 june 2015; International audience; no abstract

When nanophotonics meet thin crystalline-silicon photovoltaics

11-18 sept. 2015; International audience; no abstract