Generation of THz radiation from resonant absorption in strained multiple quantum wells in a magnetic field

Optically excited THz-radiation from ten molecular-beam epitaxy (MBE)-grown strained multiple quantum wells (MQWs) on a (100)-oriented semi-insulating GaAs substrate is studied in a 1-T magnetic field. Wavelength-dependent TH z-radiation clearly exhibits a resonance behavior at the excitation wavelen gth near 830 nm, the peak wavelength of photoluminescence (PL). We also obs erve and explain an emission spectrum from the MQW with slightly enhanced h igher-frequency components compared to that of bulk GaAs. In the thin MQW s ample, the THz emission is still significant. This indicates the possibilit y of designing MQWs as efficient THz emitters in the future.