Advanced Blue-Green Electro-Optics: Very Narrow Bandwidth, Wide Field-of-View Detectors

摘要

Underwater optical communication in the presence of ambient daytime solar illumination requires a detector with very small bandwidth (preferably or approx. = 3 steradians) and sensitivity capable of approaching the quantum limit in the 400 to 550 nm spectral range. Basic feasibility and principles of operation of Quantum-Limited Optical Resonance Detectors (QLORDs) are discussed, which exploit atomic resonance transitions in potassium, rubidium, and cesium vapors. QLORD operation is experimentally demonstrated and shown to satisfy all three basic detector requirements. A potassium detector operating at 5323.28 A matches frequency-doubled, space-qualified Nd-YAG laser transmitters, as well as at 4642.37 A or 4641.88 A, near optimum ocean transmission. A rubidium detector operates at 5165.06 A, 5165.18 A, as well as at 4215.52 A or 4201.79 A where it may match solid-state frequency-doubled Erbium-YLF transmitters. The cesium detector has been operated at 4555.28 A and 4593.17 A, and a sensitive bandwidth of 0.02 A, with an unoptimized detector sensitivity of 50 nanowatts, has been demonstrated. Measured and calculated technical data, as well as salient system parameters, are given for design and operation of the QLORD over this spectral range. (ERA citation 04:024407)