Open AccessDesign of high-Q photonic crystal microcavities with a graded square lattice for application to quantum cascade lasers
Author(s) -
Yuki Wakayama,
Aniwat Tandaechanurat,
Satoshi Iwamoto,
Yasuhiko Arakawa
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.021321
Subject(s) - photonic crystal , optics , optoelectronics , cascade , laser , semiconductor laser theory , square lattice , materials science , photonics , quantum well , dielectric , physics , condensed matter physics , chemistry , chromatography , ising model
A high-Q photonic crystal (PC) microcavity for TM-like modes, which can be applied to quantum cascade lasers (QCLs), was successfully designed in an air-hole based PC slab with semiconductor cladding layers. In spite of no photonic badgaps for TM-like modes in air-hole based PC slabs, cavity Q reached up to 2,200 by utilizing a graded square lattice PC structure. This is approximately 18 times higher than those previously reported for PC defect-mode microcavities for QCLs. This large improvement is attributed to a suppression of the coupling between the cavity mode and the leaky modes thanks to the dielectric perturbation in the graded structure. We also predicted a dramatic reduction of the threshold current in the designed cavity down to one-fifteenth of that of a conventional QCL, due to a decreased optical volume.