RESUMO
We have designed photonic crystal suspended membranes with optimized optical and mechanical properties for cavity optomechanics. Such resonators sustain vibration modes in the megahertz range with quality factors of a few thousand. Thanks to a two-dimensional square lattice of holes, their reflectivity at normal incidence at 1064 nm reaches values as high as 95%. These two features, combined with the very low mass of the membrane, open the way to the use of such periodic structures as deformable end mirrors in Fabry-Perot cavities for the investigation of cavity optomechanical effects.
RESUMO
We demonstrate the possibility of mapping the transverse spatial distribution of optical noise at the output of photonic devices. Maps of local low-frequency noise are obtained by using statistics on multiple-sampling data from near-field scanning optical microscopy (NSOM). On selected laser diodes, the signatures of basic types of transverse mode instabilities (relative phase and amplitude of modes) are unambiguously obtained. On more complex systems, the types of mode instability can be identified and their intensity can be monitored. Such noise mapping opens a new path for analyzing noise origins and for optimizing device design.
Assuntos
Análise de Falha de Equipamento/métodos , Microscopia Eletrônica de Varredura/métodos , Modelos Teóricos , Óptica e Fotônica/instrumentação , Simulação por Computador , Desenho de Equipamento , Luz , Fótons , Espalhamento de RadiaçãoRESUMO
Quantum cascade devices processed into double metal cavities with subwavelength thickness and a grating on top are studied at terahertz frequencies. The power extracted from the devices as a function of the device thickness and the grating period is analyzed owing to electrodynamical modeling of dipole emission based on a modal method in multilayer systems. The experimental data thus reveal a strong Purcell enhancement, with Purcell factors up to approximately 50.
