A Sub-Millimeter Wave Line Imaging Device

In this paper we present a single mode active device for sub-millimeter wave line imaging. The illuminated scene is imaged through focusing optics onto a device we have developed and have dubbed a spatially selective mask (SSM). This device transmits parts of the image onto a heterodyne receiver. Currently the SSM is capable of transmitting user-selectable parts of one line of the image that is focused on it. Multiple patterns are used to sample a line in the image. The voltage in the receiver resulting from each pattern constitutes an independent measurement of the illuminated scene along a line. A one dimensional image is reconstructed from the measurement results and a priori knowledge of the patterns using methods derived from the theory of compressive sensing. The theory behind the device and the design principles we use are reviewed. We show line images obtained at 640 GHz. Extension of this technique to two dimensional imaging is discussed.