Optical resonance tuning and polarization of thin-walled tubular microcavities

摘要

We present experimental and finite-difference time-domain simulation results on the tunability of opticalnresonant modes of spiral microtube cavities, rolled-up from square patterned SiO/SiO2 thin nanomem-nbranes on glass substrates. The peak positions of resonant TM modes shift to lower energies by coating thenmicrotube wall with Al2O3 monolayers, which is well described by simulations. Moreover, a second group ofntunable resonant modes appears beyond a certain critical thickness of the coated Al2O3. The polarization ofnthis group of modes is TE, as we find out by a detailed analysis of the polarization-dependent photolumi-nnescence spectra. © 2009 Optical Society of America