Three-Dimensional Anisotropic Microlaser from GaN-Based Self-Bent-Up Microdisk

Abstract

Microcavities with whispering gallery modes (WGM), usually formed by two-dimensional (2D) circular structures, are significant elements in integrated optics, quantum information, and topological photonics. We report three-dimensional (3D) WGM from self-bent-up microdisks consisting of strain-released AlGaN/GaN bilayers, which provide an extra degree of freedom of the WGM photons in the vertical dimension, in contrast with the 2D WGM whose field mainly distributes in the horizontal plane. Despite the ultrathin and deformed cavity layer, the 3D WGM shows a reasonably high quality factor for GaN-based microdisks (∼1300) and exhibits single mode lasing due to the anisotropic feature of the bent-up disk, a unique advantage over the conventional planar microdisks of the same material and size. Such devices provide altitude dependence of emitting direction and are promising for applications in multilevel integrated photonics circuits.

Tunable Open‐Access Microcavities for Solid‐State Quantum Photonics and Polaritonics

“…One of the elementary excitations in semiconductors is the exciton, a bound state of an electron and a hole via Coulomb interaction that can be created and annihilated by absorbing and emitting a photon. The cavity with an exciton inside is described by the Hamiltonian of the coupled system [21] H = ω câ †â + ω Xb †b + g â †b +b †â + αb †b †bb (10) whereâ andb are the annihilation operators of a cavity photon and an exciton respectively, and ω c and ω X are the resonance frequencies of the cavity and exciton modes. The third term describes the exciton-cavity coupling, which adds off-diagonal elements to the Hamiltonian, resulting in new eigenstates for the coupled system named exciton-polaritons.…”

“…[2,3] Otherwise, the system stays in the weak coupling regime in which the emitter and cavity lifetimes are modified by each other, resulting in cavity-enhanced or cavity-prohibited spontaneous emission, known as the Purcell effect. [4,5] Microcavities play a significant role in a wide range of research areas including light-matter interaction, [2] nonlinear optics, [6] quantum information, [7] and topological photonics, [8,9] serving as crucial elements of on-chip microlasers, [10] optical switches, [11] isolators, [12,13] sensors, [14] photonic logic gates, [15] quantum simulators, [16,17] and high-efficiency quantum light sources. [18] The main advantage of the microcavities over the macroscopic cavities is the small mode volume that is a necessity for enhancing light-matter interaction.…”

“…Microcavities play a significant role in a wide range of research areas including light–matter interaction, nonlinear optics, quantum information, and topological photonics, serving as crucial elements of on‐chip microlasers, optical switches, isolators, sensors, photonic logic gates, quantum simulators, and high‐efficiency quantum light sources . The main advantage of the microcavities over the macroscopic cavities is the small mode volume that is a necessity for enhancing light–matter interaction.…”

Ultra-thin curved visible microdisk lasers with three-dimensional whispering gallery modes

“…Usually, the WGMs show a two-dimensional (2D) spatial intensity distribution in the horizontal plane of mechanically inflexible 2D planar microdisk lasers, owing to the high intrinsic stiffness. While, 3D WGMs can provide an extra degree of freedom for the confined photons compared with 2D WGMs, which can be realized by directly growing strained semiconductor active layers based on the selfrolling-up mechanism [14].…”

“…Here, we demonstrated ultra-thin curved visible microdisk lasers with a thickness ∼80 nm, of which the 3D curved architecture is formed by strain induced rolling mechanism [14][15][16]. Compared with directly epitaxial growth of stained active layers for self-rolling microcavities [14,16], the strain relaxation of active materials was achieved by wet-etching the III-V cladding layers from a generally thick planar structure. The method used here makes it possible to achieve strain relaxation of grown thick III-V slab structures for a wide range of material systems.…”