Coherent millimeter-wave generation by heterodyne conversion in low-temperature-grown GaAs photoconductors

Abstract

An analysis has been carried out of optical heterodyne conversion with an interdigitated-electrode photomixer made from low-temperature-grown (LTG) GaAs and pumped by two continuous-wave, frequency-offset pump lasers. The analytic prediction is in excellent agreement with the experimental results obtained recently on a photomixer having 1.0~pm-wide electrodes and gaps. The analysis predicts that a superior photomixer having 0.2~pm-wide electrodes and gaps would have a temperature-limited conversion efficiency of 2.0% at a low difference frequency, 1.6% at 94 GHz, and 0.5% at 300 GHz when connected to a broadband 100 fi load resistance and pumped at hv=2.0 eV by a total optical power of 50 mW. The predicted 3-dB bandwidth (193 GHz) of this photomixer is limited by both the electron-hole recombination time (0.6 ps) of the LTG-GaAs material and the RC time constant (0.5 ps) of the photomixer circuit.

Quantum dot materials for terahertz generation applications

“…Such carrier lifetime shortening mechanisms in the QD structure has also been reported earlier in similar structures [8], and were confirmed for our samples later [36]. In addition to pulsed THz signals, CW THz radiation by heterodyne conversion [37] may be generated. We have already demonstrated the CW THz emission by photomixing of ∼850 nm laser diodes pump in optimised QD structures [13].…”

Generation of Terahertz radiation with two color semiconductor lasers

“…Accordingly, the most common concept for the generation of cw THz radiation with diode laser sources is photomixing. The concept is described in detail in the literature [47,48] and we review it only shortly here. The basic idea is shown in Fig.…”

Four-leaf Clover-shaped Antenna for THz Photomixer for High Output Power

“…연속파 광원기술로 포토믹서(photomixer)와 핫홀 레이저 (hot hole laser), 자유전자 레이저 (free electron laser), 양자 캐스 케이드 레이저 (quantum cascade laser) 등이 있으나, [10][11][12][13] …”