Optically-switched submillimeter-wave oscillator and radiator having a switch-to-switch propagation delay

A free-space radiating multi-watt submillimeter wave source, comprising:

• an integrated circuit substrate;
• an optically active semiconductor layer overlying said substrate;
• a linear array of opposing metal finger pairs overlying said optically active layer with thin gaps between opposing fingers of each pair, adjacent ones of said gaps being separated by a uniform spacing D for a gap-to-gap propagation delay corresponding to a submillimeter wave frequency regime;
• a pair of bias bus conductors connected to respective ones of said opposing metal finger pairs;
• an antenna connected at a first terminal thereof to one of said bias bus conductors at one end of said linear array;
• and
• a thin film capacitor having one capacitor plate overlying a major portion of one of said bias bus conductors and connected to a second terminal of said antenna and a dielectric layer lying between said capacitor plate and the underlying one bias bus conductor.

A submillimeter wave-generating circuit, comprising:

• a two-dimensional planar array of photoconductive switches comprising plural linear arrays of said plural photoconductive switches;
• means for biasing said switches across a common voltage source;
• an output load connected to one end of each one of said linear arrays;
• and
• means for applying an optical pulse beam of repetition rate f.sub.0 to said plural switches so as to generate electrical pulses from said switches traveling along each one of said linear arrays toward the respective output loads, wherein said plural switches within each linear array are spaced apart by a spacing D to provide a corresponding switch-to-switch propagation delay of said electrical pulses, whereby arrival times of said electrical pulses at each one of said output loads are spaced apart by an arrival period corresponding to a desired submillimeter wave frequency f which is a function of said switch-to-switch propagation delay.

A submillimeter wave source, comprising:

• a photoconductive switch biased across a voltage source and having an output load coupled thereto;
• means for generating multiple delayed reflections of a single pulsed optical beam of repetition rate f.sub.0, successive ones of said reflections being spaced in time by successive optical delay differences corresponding to a submillimeter wave frequency f;
• and
• means for focusing said multiple delayed reflections of said beam onto said photoconductive switch.