n-Type GaAs/AlGaAs heterostructure detector with a 3.2 THz threshold frequency.

Terahertz detection using the free-carrier absorption requires a small internal work function of the order of a few millielectron volts. A threshold frequency of 3.2 THz (93 microm or approximately 13 meV work function) is demonstrated by using a 1 x 10(18) cm(-3) Si-doped GaAs emitter and an undoped Al(0.

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

The quality factor (Q), mode volume (V(eff)), and room-temperature 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 Veff can be as small as 2(lambda/n)(3) while maintaining radiation-limited Qs in excess of 10(5). Microdisks of diameter 2 microm are fabricated in an AlGaAs material containing a single layer of InAs QDs with peak emission at lambda = 1317 nm.