Statistical analysis of optical up-conversion passive imager receiver and image quality

Passive millimeter and terahertz wave imaging have emerged as a promising human security screening and scene surveillance technique. Due to the minimal contrast in brightness temperatures between the human body and concealed objects, enhancing the temperature sensitivity and spatial resolution of radiometers remains challenging. The measure of system sensitivity is noise equivalent temperature difference (NEΔT) and probability of detection (Pd). While conventional RF receivers down-convert the received signal using a mixer and local oscillator for image rendering, herein we present the latest developments of a state-of-the-art optical up-conversion receiver that up-converts the received RF signal onto the sideband of an optical carrier across a phased array antenna. After up-conversion, each signal is routed back to an optical fiber bundle that is subsequently spatially Fourier-transformed using a lens to render an image. In this presentation, a theoretical study and system-level simulations are used to illustrate the efficacy of this approach in terms of Pd.