Optical loss and lasing characteristics of high-quality-factor AlGaAs microdisk resonators with embedded quantum dots

Optical characterization of AlGaAs microdisk resonant cavities with a quantum dot active region is presented. Direct passive measurement of the optical loss within AlGaAs microdisk resonant structures embedded with $\mathrm{In}\mathrm{As}∕\mathrm{In}\mathrm{Ga}\mathrm{As}$ dots-in-a-well (DWELL) is performed using an optical-fiber-based probing technique at a wavelength $(\lambda \sim 1.4\mu \mathrm{m})$ that is red detuned from the dot emission wavelength $(\lambda \sim 1.2\mu \mathrm{m})$ . Measurements in the $1.4\mu \mathrm{m}$ wavelength band on microdisks of diameter $D=4.5\mu \mathrm{m}$ show that these structures support modes with cold-cavity quality factors as high as $3.6\times {10}^5$ . DWELL-containing microdisks are then studied through optical pumping at room temperature. Pulsed lasing at $\lambda \sim 1.2\mu \mathrm{m}$ is seen for cavities containing a single layer of InAs dots, with threshold values of $\sim 17\mu \mathrm{W}$ , approaching the estimated material transparency level. Room-temperature continuous-wave operation is also observed.