Frequency difference generation in the terahertz region using LTG-GaAs photodetector
Résumé
We demonstrated Terahertz generation by optical frequency difference with a continuous tuning between 0.2 1 micro W and 3 THz 1 nW. To this aim, high speed photodetectors with an interdigited photoconductor scheme on a submicron scale, loaded by THz log-periodic antennas, were deposited on a 1 micrometer-thick Low Temperature Grown 200 deg C GaAs epilayer. Two TiSapphire laser beams 30 mW focused onto the device yield Terahertz radiation collimated through Silicon lens and detected by means of lock-in bolometer detection. The generated power and frequency, consistent with semiconductor and circuit time constants, are discussed in the prospects of antenna arrays and optical cavities.