AIP Digital Archive
Electrical Engineering, Measurement and Control Technology
We have built a relatively simple, highly efficient, THz emission and detection system centered around a 15 fs Ti:sapphire laser. In the system, 200 mW of laser power is focused to a 120 μm diam spot between two silverpaint electrodes on the surface of a semi-insulating GaAs crystal, kept at a temperature near 300 K, biased with a 50 kHz, ±400 V square wave. Using rapid delay scanning and lock-in detection at 50 kHz, we obtain probe laser quantum-noise limited signals using a standard electro-optic detection scheme with a 1-mm-thick (110) oriented ZnTe crystal or a (110) oriented 0.1-mm-thick GaP crystal. The maximum THz-induced differential signal that we observe is ΔI/I=7×10−3, corresponding to a THz peak amplitude of 95 V/cm. The THz average power was measured to be about 40 μW, to our knowledge, the highest power reported so far generated with Ti:sapphire oscillators as a pump source. The system uses off-the-shelf electronics and requires no microfabrication techniques. © 2002 American Institute of Physics.
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