Patent ID: 7929580

Claim:
Apparatus for generating pulses of electromagnetic signals in a terahertz region, comprising: a mode-locking generator for supplying a first electrical signal and a second electrical signal, said mode-locking generator operatively arranged to shift a phase of the first electrical signal to generate the second electrical signal; a first mode-locked semiconductor laser diode for supplying first pulses of light, with the mode-locking of said first semiconductor laser diode controllable so that a phase of the first pulses of light is controlled by the first electrical signal; a first Auston switch optically coupled to said first laser diode, said first Auston switch being biased so that, when said first pulses of light from said first laser diode are incident on said first Auston switch, corresponding electromagnetic pulses are generated in the terahertz region; a second mode-locked semiconductor laser diode for supplying second pulses of light, with the mode-locking of said second semiconductor laser diode controllable so that a phase of the second pulses of light is controlled by the second electrical signal; and a second Auston switch optically coupled to said second laser diode to receive said second pulses of light, said second Auston switch being unbiased and being arranged to receive at least a portion of the energy of said terahertz region pulses.