Modelling and fabrication of GaAs photonic-crystal cavities for cavity quantum electrodynamics

Abstract

In this paper, we present recent progress in the growth, modelling, fabrication and characterization of gallium arsenide (GaAs) two-dimensional (2D) photonic-crystal slab cavities with embedded indium arsenide (InAs) quantum dots (QDs) that are designed for cavity quantum electrodynamics (cQED) experiments. Photonic-crystal modelling and device fabrication are discussed, followed by a detailed discussion of different failure modes that lead to photon loss. It is found that, along with errors introduced during fabrication, other significant factors such as the presence of a bottom substrate and cavity axis orientation with respect to the crystal axis, can influence the cavity quality factor (Q). A useful diagnostic tool in the form of contour finite-difference time domain (FDTD) is employed to analyse device performance.

Progress in growth, fabrication, and characterization of semiconductor photonic crystal nanocavities

“…We observe that the cavity Qs depend on polarization of the light in the fiber, of contact position on the nanobeam, and of angle between the nanobeam and the fiber [12]. We also present recent progress in the growth and fabrication of 2D photonic crystal slab nanocavities in GaAs with InAs QDs [6,7]. Fig.…”

“…Higher values of Q lead to longer photon lifetimes in the cavity (improved chance of light-matter interaction), and smaller values of V lead to higher field intensities (stronger light-matter interaction). The importance of the ratio Q/V can be seen in the expression for Purcell enhancement (F p / Q/V) of spontaneous emission and for vacuum Rabi splitting (VRS / Q/HV) [1,2,[5][6][7]. The pursuit of high Q, small V nanocavities has thus been a major focus of efforts in the semiconductor cavity QED community.…”

Soft-mask fabrication of gallium arsenide nanomembranes for integrated quantum photonics

“…There are situations, however, where introducing an additional mask layer is not desirable, especially when oxides or metals have been already deposited on the sample for other purposes, e.g., for the fabrication of superconducting single photon detectors [16]. In this letter we present a soft-mask process where a circuit is etched directly into a GaAs membrane through the patterned electron-beam resist [17,18]. Unlike hard-mask processes, this method involves fewer fabrication steps, reduces the need for expensive deposition equipment and operates at lower temperatures.…”

High-Q Defect-Free 2D Photonic Crystal Cavity from Random Localised Disorder

“…Inevitably, the inability to accurately fabricate features with a size which is on the order of a visible wavelength leads to imperfection. Structural characteristics which are affected during fabrication include surface roughness, sidewall angle, and the size and position of holes [25]. This has attracted much research to determine the tolerance of structures to variation of physical parameters which perturb the photonic bandgap [19,[26][27][28].…”