Toward Better Light-Confinement in Micropillar Cavities

Abstract

We report on a two-step etching of ZnTe based micropillars. We demonstrate applicability of the technology and we analyze the optical properties of obtained structures. Microphotoluminescence spectra of individual micropillars show a typical mode pattern that confirms a successful growth of photonic structures. The reflectivity and photoluminescence spectra of a planar microcavity measured for various incident angles show that additional side distributed Bragg reflectors will be important for the further enhancement of photon confinement in micropillar cavity.

Inhibition and Enhancement of the Spontaneous Emission of Quantum Dots in Micropillar Cavities with Radial-Distributed Bragg Reflectors

“…A photoresist layer on top of the micropillar, which can be seen in Figure 2b, results from an optional twostep etching procedure of the initial micropillars described in ref 15.…”

“…It is a channel through which emitters in micropillars emit photons even if the emission energy is not a resonant energy of the micropillar. As observed for edge emission from planar cavities, 15 this channel is so effective that no inhibition of the emission is observed for detuned emitters. 16À18 Leaky modes also deteriorate the efficiency of single-photon sources, as their presence prevents the emitter from coupling 100% into the desired mode.…”

“…It is a channel through which emitters in micropillars emit photons even if the emission energy is not a resonant energy of the micropillar. As observed for edge emission from planar cavities, this channel is so effective that no inhibition of the emission is observed for detuned emitters. − Leaky modes also deteriorate the efficiency of single-photon sources, as their presence prevents the emitter from coupling 100% into the desired mode. For these reasons an inhibition of the unwanted emission into leaky modes, which outcouples QD emission in the undesirable planar direction, is one of the major challenges in the micropillar-based cavity technology.…”

MBE grown microcavities based on selenium and tellurium compounds

“…The best quality factor was obtained for microcavities in the mixed selenium/tellurium system. Such structures have already been studied [33,34,35,36,37], but we extend the range of application to shorter wavelengths (down to 563 nm - Fig. 5 b).…”

Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities

“…A pronounced photonic band gap and photonic modes are present only in the growth direction. The emitter can therefore couple to a quasi-continuum of "leaky" photon modes [22,23] and photons can be emitted in directions off the growth axis and collected due to a large numerical aperture of the lens used in the experiment (0.68).…”