In 1998, Bender and Boettcher found that a wide class of Hamiltonians, even though non-Hermitian, can still exhibit entirely real spectra provided that they obey parity-time requirements or PT symmetry. Here we demonstrate experimentally passive PT-symmetry breaking within the realm of optics. This phase transition leads to a loss induced optical… (More)
We study experimentally and numerically the nonlinear scattering of wave packets by local multisite guiding centers embedded in a continuous dielectric medium as a function of the input power and angle of incidence. The extent of trapping into the linear modes of different sites is manipulated as a function of both the input power and the angle of… (More)
We report on design, simulation and fabrication of ultimate and compact 3D close-geometries optical microcavities. These are based on the extension of the so-called 2.5D nanophotonic approach where a quasi 3D control of the photons has been soon demonstrated by our group. A tight control of photons, spectrally and spatially, in a small air region inside a… (More)
We report on Chemical Beam Epitaxy (CBE) growth of wavelength tunable InAs/GaAs quantum dots (QD) based superluminescent diode's active layer suitable for Optical Coherence Tomography (OCT). The In-flush technique has been employed to fabricate QD with controllable heights, from 5 nm down to 2 nm, allowing a tunable emission band over 160 nm. The emission… (More)
The high power density in AlGaN/GaN High Electron Mobility Transistors (HEMTs) can notably produce strong self-heating in the device. This effect leads to performance degradation and reliability concerns. Thermal performance of the device is strongly dependent on the epitaxial structure and substrate material. This work puts into perspective the thermal… (More)
We report on the investigation of the coupling between the high-Q mode of a tri-dimensional hollow silicon-based micro-resonator and PbS quantum dots in the near-infrared range, using near-field scanning optical microscopy and far-field spectroscopy.
Modal phase-matched second harmonic generation is obtained in sub-micron AlGaAs waveguides using a continuous-wave laser at telecommunication wavelengths. The tunability and robust fabrication process make this device ideal for integrated wavelength conversion.
We propose a tunable hybrid silicon evanescent laser with vertical sidewalled sampled grating distributed Bragg reflectors (SG-DBR) on SOI. The device utilizes a Vernier comb and the electrooptic effect in silicon for tuning within a 30 nm range.
Superluminescent diodes are used in numerous sensing and testing applications. To achieve the wide emission spectrum and high power required from such devices, we studied an innovative design constituting in several different bandgap energy sections independently electrically pumped. Bandgap modification was obtained by the UV laser quantum well intermixing… (More)