Quantum dot photonic crystal lasers

Coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot photonic crystal lasers at room temperature. Threshold pump powers of 120 and 370 μW were observed for coupled cavities including two and four defect cavities defined in optimised photonic crystals

High spontaneous emission coupling factor in photonic crystal nanolasers

We have demonstrated high spontaneous emission coupling factor ~ 0.1 from photonic crystal nanolasers with quantum dots. This high coupling resulted from narrow homogenous broadening of the quantum dots and the small number of resonances

Scanning a photonic crystal slab nanocavity by condensation of xenon

Allowing xenon or nitrogen gas to condense onto a photonic crystal slab nanocavity maintained at 10–20 K results in shifts of the nanocavity mode wavelength by as much as 5 nm (~=4 meV). This occurs in spite of the fact that the mode defect is achieved by omitting three holes to form the spacer. This technique should be useful in changing the detuning between a single quantum dot transition and the nanocavity mode for cavity quantum electrodynamics experiments, such as mapping out a strong coupling anticrossing curve. Compared with temperature scanning, it has a much larger scan range and avoids phonon broadening

High spontaneous emission coupling factor in photonic crystal nanolasers

We have demonstrated high spontaneous emission coupling factor ~ 0.1 from photonic crystal nanolasers with quantum dots. This high coupling resulted from narrow homogenous broadening of the quantum dots and the small number of resonances

Quantum dot photonic crystal nanocavities: Transition from weak to strong coupling and nonlinear emissions

Photonic crystal slab nanocavities containing one layer of quantum dots have exhibited: strong coupling to a single quantum dot; tuning by condensation of xenon gas; linewidth broadening due to ensemble dot absorption; gain and lasing

Time-resolved Faraday rotation measurements of spin relaxation in InGaAs/GaAs quantum dots: Role of excess energy

The authors report measurements of room temperature spin dynamics in InGaAs quantum dots using time-resolved differential transmission and Faraday rotation techniques. They observe an enhancement of the electron spin lifetime by an order of magnitude for direct optical pumping of the quantum dot ground state compared to optical pumping of the GaAs barriers. These findings indicate that the optical excitation conditions can have a critical influence on the spin kinetics, a result which may account for the wide variation of spin lifetimes reported to date. The enhancement in spin lifetime observed here is attributed to the reduction of phonon-mediated spin-flip scattering

Strong-coupling and nonlinear emission from a quantum-dot photonic-crystal-slab nanocavity

An InAs quantum dot in a photonic crystal nanocavity exhibits vacuum Rabi splitting (strong coupling); a clear anti-crossing is seen between the quantum dot transition and the nanocavity mode as the temperature is scanned