The optical losses in dry-etched monolithic microresonators have been studied as a function of their lateral dimensions. Cylindrical microresonators with various radii have been etched from a planar GaAlAs/GaAs microcavity with a very high quality factor (Q≅11 700). Measurements of the resonance linewidth, using Ti-sapphire laser spectroscopy allowed to study the degradation of the Q factor at small radii. The Q factor is four times smaller in 1.1 μm radius microresonators, compared to the unprocessed cavity. This degradation is attributed to optical scattering from sidewalls, whose efficiency is shown to scale with the guided mode intensity at the microresonator edge.

We demonstrate second-harmonic generation in a doubly resonant semiconductor microcavity. The monolithic cavity consists of an AlGaAs active medium sandwiched between two AlGaAs/AlAs dual-wavelength mirrors. The mirrors do not have any apparent periodicity because, unlike single- or dual-wavelength Bragg reflectors, they are engineered with dispersion taken into account. Quasi-phase matching is obtained by addition of the appropriate phases at reflection so as to compensate for the dephasing between the fundamental and the second-harmonic fields.

Articles you may be interested inDifferential surface photovoltage spectroscopy characterization of a 1.3 μm InGaAlAs/InP vertical-cavity surfaceemitting laser structure Resonances between the cavity mode and five excitonic transitions in an In x Ga 1−x As/GaAs/AlAs/AlGaAs vertical-cavity surface-emitting laser structure using photomodulated reflectance

A monolithic vertical cavity bistable device based on the InGaAlAs system has been grown by low pressure metalorganic vapor phase epitaxy in a single run. First observation of all-optical bistability is reported in this new monolithic structure, with a contrast of 15:1 and a threshold power of less than 300 μW. X-ray diffraction and reflectivity measurements confirmed the high crystallographic and optical qualities of the material. This result shows that the InGaAlAs system is well suited to the fabrication of vertical cavity devices in the optical communication wavelength range.

We have investigated a 1.3 m InGaAlAs/InP vertical-cavity surface-emitting laser ͑VCSEL͒ structure using angle-and temperature-dependent wavelength-modulated differential surface photovoltage spectroscopy ͑DSPS͒. The DSPS measurements as functions of incident angle and temperature have been carried out in the ranges 0°рр60°and 300 KрTр420 K, respectively. Angle-dependent reflectance ͑R͒ and surface photovoltage spectroscopy ͑SPS͒ measurements have also been performed to illustrate the superior features of the DSPS technique. The differential surface photovoltage ͑DSPV͒ and SPV spectra exhibit both the fundamental conduction to heavy-hole excitonic transition of quantum well and cavity mode ͑CM͒ plus a rich interference pattern related to the mirror stacks, whereas in the R spectra only the CM and interference features are clearly visible. The energies of the excitonic transition and CM are accurately determined from the DSPV spectra. By changing the angle of incidence in the DSPS measurements the energy positions of the CM and distributed Bragg reflector features show a blueshift while the excitonic transition remains unchanged. At a fixed incident angle, the energy positions of the excitonic feature and CM show a different rate of redshift with increasing temperature, with the latter at a much slower pace. The results demonstrate considerable potential of DSPS for the nondestructive characterization of the VCSEL structures.