OPTICAL SWITCHES AND DETECTORS UTILIZING INDIRECT NARROW-GAP SUPERLATTICES AS THE OPTICAL MATERIAL.

摘要

The present invention relates to novel optical devices operating in the infrared, based on indirect narrow-gap superlattices (INGS) as the active optical materials. The novel optical devices include (1) wideband all-optical switches, which combine small insertion loss at low light intensities with efficient optical switching and optical limiting at high efficiency and low tunneling noise currents, suitable for use in longwave infrared focal plane arrays. INGS comprise multiple semimetal (22) semiconductor (26) layers having compatible crystal symmetry across each heterojunction between a given semimetal (22) sandwiched between semiconductor layers (26). Each semiconductor layer (26) is thin enough that there is coupling between adjacent semiconductor layers (26). The present invention utilizes INGS, which are fabricated to meet the criteria Eindg θφ Edirg, especially where θφ 100 meV, as the optical material for optical switches. The present invention also utilizes INGS as optical detectors if they are fabricated such that Eindg Edirg θφ, especially where θφ is less than 100 meV.