Strong light-matter coupling in ultrathin double dielectric mirror GaN microcavities

Strong light-matter coupling is demonstrated at low temperature in an ultrathin GaN microcavity fabricated using two silica/zirconia Bragg mirrors, in addition to a three-period epitaxial (Al,Ga)N mirror serving as an etch stop and assuring good quality of the overgrown GaN. The λ/2 cavity is grown by molecular beam epitaxy on a Si substrate. Analysis of angle-resolved data reveal key features of the strong coupling regime in both reflectivity and transmission spectra at 5 K: anticrossing with a normal mode splitting of 43±2 meV and 56±2 meV for reflectivity and transmission, respectively, and narrowing of the lower polariton linewidth near resonance

Mode Coupling and Intersubband Transition Rabi Splitting in Microcavities

We theoretically study the absorption in grating coupled quantum wells in a cavity. We describe the coupling between the three oscillators present in the structure: the intersubband transition, the grating and cavity modes. We show that optical mode anticrossings should be observed. The splitting between the cavity mode and the intersubband transition is calculated but its experimental observation would require electronic coherence times longer than what was measured

Light-ion beam for microelectronic applications

In this paper we describe the structure and the composition of (Al,Ga)N/GaN Bragg reflectors obtained from Rutherford backscattering spectroscopy. Bragg reflectors constitute a part of blue ($\lambda$ = 450 nm) resonant cavity light emitting diodes. To improve the measurement accuracy, three tilt angles have been used (10\degres, 25\degres and 50\degres). In a second part of the paper, ion beam induced charges study has been carried out, with a 2 MeV $^4$He$^+$ micro-beam, on metal–semiconductor–metal UV photodetectors. Results have been taken into account for the design of the photodetector electrodes

Recent ROB developments on wide bandgap based UV sensors

The next ESA spatial mission planned to study the Sun, Solar Orbiter (SO), necessitates very innovative EUV detectors. The commonly used silicon detectors suffer important limitations mainly in terms of UV robustness and dark current level. An alternative comes from diamond or III-nitride materials. In these materials, the radiation hardness, solar blindness and dark current are improved due to their wide bandgap. This paper presents the new developments on wide bandgap materials at the Royal Observatory of Belgium (ROB). We present also the LYRA instrument, the BOLD project, and the EUI instrument suite

Effect of In-segregation on subbands in GaInNAs/GaAs quantum wells emission around 1.3 and 1.55 micron

10.1007/s11082-006-9042-8Optical and Quantum Electronics3812-14963-972OQEL