Patent ID: 7897924

Claim:
An apparatus for imaging an area at extended THz frequencies, comprising: an electro-magnetic wave source generating a continuous wave or pulsed output, generated coherently or incoherently; steering optics for the electro-magnetic wave, the steering optics providing angular variation of the wave onto the focusing optics; an optical converter converting an angular variation of an incident wave into a lateral variation; focusing optics focusing the electro-magnetic wave at or within a target to be imaged; collecting optics collecting the electro-magnetic wave leaving the target; an electro-magnetic wave detector detecting the collected wave, a frequency range of the electro-magnetic wave being between 1 GHz to 100 THz, said steering optics and focusing optics being configured so that the wave is focused on a planar region, and in a normal direction to the region, over substantially the entire image area, the collecting optics being arranged to receive the wave to be imaged along one or both of a co-propagation and counter-propagation direction relative to the wave incident on the target over substantially the entire image area, and to deliver energy from at least a portion of the collected wave to the electro-magnetic wave detector during steering of the wave, at least a portion of said steering optics, focusing optics, and collecting optics comprising a beam path compensator to limit one or both of beam walking and temporal variation of an optical path during steering of the wave, said wave to be imaged carrying spectral information in reflection, transmission, scattering, refraction or diffraction arranged to the specular direction.