GHz modulation of tunable THz radiation from photomixing at 1.55μm

摘要

We report the transfer of a GHz modulation from an optical carrier at telecom wavelengths to a free space THz beam. THz radiation -tunable from 300GHz to 1.2THz- is generated by mixing two telecom lasers with an offset frequency in an ultrafast In{sub}0.53Ga{sub}0.47As photoconductive device coupled to a broadband antenna. A maximum modulation rate of 20GHz has been achieved, and the bandwidth is independent of the carrier frequency.