THz Emission Studies on Semiconductor Alloy, InAsBi

This paper reports the measurements of the THz emission from InAs films which have been grown by molecular beam epitaxy on a semi-insulating (100) GaAs substrate without, and with different Bi fluxes. The emission is excited with a femtosecond pulsed Er-Fibre laser (λ ~ 1550 nm, 100 fs). The set of InAs film samples are without Bi and with different percentage of Bi. The fs pulsed laser beam is directed onto the sample surface at an angle of incidence 45°. The output THz radiation is collamated through a pair of parabolic lenses through a Germanium detector to remove all non-THz radiation, and finally focussed onto a Microtech Golay cell. An optical chopper set at 20Hz is placed between the collimating optics and the bolometer to provide a reference for a Stanford SR580 lockin amplifier, which takes as an input the Goley cell signal output