Search NASA⌕ Search

Engineering topics

Shaner, Eric A.

Publications and source records attributed to Shaner, Eric A..

All-epitaxial resonant cavity enhanced long-wave infrared detectors for focal plane arrays

Here, we demonstrate a monolithic all-epitaxial resonant-cavity architecture for long-wave infrared photodetectors with substrate-side illumination. An nBn detector with an ultra-thin (t ≈ 350 nm) absorber layer is integrated into a leaky resonant cavity, formed using semitransparent highly doped (n⁺⁺) epitaxial layers, and aligned to the anti-node of the cavity’s standing wave. The devices are characterized electrically and optically and demonstrate an external quantum efficiency of 25% at T ¼ 180 K in an architecture compatible with focal plane array configurations.

42 ENGINEERING↗

Tunable coherent light filter for optical sensing and imaging

Systems and methods are provided for filtering coherent infrared light from a thermal background for protection of infrared (IR) imaging arrays and detection systems. A Michelson interferometer is used for coherent light filtering. In an implementation, a system includes a fixed mirror, a beam splitter, and a moving mirror which can be controlled translationally, as well as tip/tilt. The Michelson interferometer may be used as an imaging system. For imaging applications, a system may comprise a tunable array of micro-electromechanical systems (MEMS) mirrors. A mid-wave IR interferometer with electronic feedback and MEMS mirror array is provided.

Wasserman, David↗

Apparatus and method to measure semiconductor optical absorption using microwave charge sensing

A time-resolved microwave reflectance apparatus comprises a pulsed or modulated optical source that irradiates a semiconductor sample with an excitation pump beam, a microwave oscillator that irradiates the sample with a continuous beam of microwaves, and a microwave detector that detects the microwaves reflected by the sample. Therefore, charge detection, rather than conventional absorption measurements (that detect the loss of photons), can be used to extract the absorption coefficient and band edge of a semiconductor material.

Shaner, Eric A.↗