Cavity Q, mode volume, and lasing threshold in small diameter AlGaAs microdisks with embedded quantum dots

Abstract

Abstract:The quality factor (Q), mode volume (V eff ), and roomtemperature lasing threshold of microdisk cavities with embedded quantum dots (QDs) are investigated. Finite element method simulations of standing wave modes within the microdisk reveal that V eff can be as small as 2(λ/n) 3 while maintaining radiation-limited Qs in excess of 10 5 . Microdisks with a 2 µm diameter are fabricated in an AlGaAs material containing a single layer of InAs QDs with peak emission at λ = 1317 nm. For devices with V eff ∼2 (λ/n) 3 , Qs as high as 1.2×10 5 are measured passively in the 1.4 µm band, using an optical fiber taper waveguide. Optical pumping yields laser emission in the 1.3 µm band, with room temperature, continuous-wave thresholds as low as 1 µW of absorbed pump power. Out-coupling of the laser emission is also shown to be significantly enhanced through the use of optical fiber tapers, with a laser differential efficiency as high as ξ ∼ 16% and out-coupling efficiency in excess of 28% measured after accounting for losses in the optical fiber system.

Dielectric microcavities: Model systems for wave chaos and non-Hermitian physics

“…The Purcell enhancement of optical density of states by the WGM dramatically increases light emission and scattering (Chang and Campillo, 1996;Vahala, 2004). Strong coupling of a single emitter (atom or quantum dot) to a WGM of a microdisk or a microtoroid has been achieved (Aoki et al, 2006;Peter et al, 2005;Srinivasan and Painter, 2006), facilitating the studies of cavity quantum electrodynamics. The strong buildup of intracavity optical field greatly enhances nonlinear coupling of light with matter (Chang and Campillo, 1996).…”

Room-temperature continuous wave lasing in deep-subwavelength metallic cavities under electrical injection

“…Size reduction of semiconductor lasers have in the past enabled studies of many rich physics on an ever decreasing spatial scale and the development of many technological applications. The quantum optics and laser physics community has witnessed dramatic progress over the past few decades in making increasingly smaller lasers using pure dielectric structures such as microdisk lasers, [15][16][17] photonic wire lasers, 18 photonic crystal (PC) lasers, [19][20][21][22] or nanowire lasers. 10,[23][24][25][26] These lasers represented the smallest lasers made of pure dielectric structures, and further miniaturization becomes exceedingly challenging.…”

Observation of whispering gallery modes from hexagonal ZnO microdisks using cathodoluminescence spectroscopy

“…Microdisk resonators support propagation of whispering gallery modes (WGMs), enabling technologies such as bright LEDs, sensing, and low threshold lasers. [8][9][10][11] For the WGMs emission, the light wave propagates circularly around the interface of material/air due to multiple total internal reflections. As a result, the optical losses can be significantly reduced so that the WGMs can provide an attractive means to increase luminescence efficiency in optical resonators.…”