New quantum-based communication and measurement systems that use single and correlated photons have been developed; however, the current tools for calibrating the components in these systems are inadequate for the emerging applications. For accurate calibration, a detector capable of determining the number of photons in a single pulse of light is needed. We are developing high-effi ciency detector systems with this capability in the three telecommunication windows (850 nm, 1310 nm, and 1550 nm). These new instruments will also aid in the understanding and advancement of new photon sources such as the single-photon turnstile and entangled photon sources. They can be used as a spectroscopic diagnostic tool or characterization tool for optical elements, optical materials, and optical systems at ultralow light levels. A near-term use of the detectors is for research in quantum key distribution, a method of communication where security is assured by the laws of quantum mechanics rather than by mathematical complexity.

Imaging in the ~100 GHz to ~2 THz range offers the possibility of concealed weapons detection and remote detection of contraband (for example, explosives under clothing) without the use of ionizing radiation. Spectroscopy in this frequency range has additional applications in industrial processing and remote identifi cation of chemicals. Industry and government agencies require unique capabilities in detectors, optics, and metrology methods and test-beds for improved imaging systems and unbiased, calibrated evaluations of systems and components.

Contact: Dr. Sae Woo Nam