Paul W. Kruse

Integrated uncooled infrared detector imaging arrays

The authors describe a new type of infrared (IR) focal plane consisting of a 2-D array of microminiature bolometers (microbolometers) fabricated, complete with readout electronics, as a monolithic silicon chip. These focal planes require no cooling for sensitive detection of IR radiation. The authors report high-quality IR imaging obtained with such focal planes.<<ETX>>

High-temperature superconducting microbolometer

A superconducting microbolometer employing a DyBaCuO film deposited upon a silicon microstructure was found to have a responsivity of 800 V/W at 89 K and a response time of 1 ms.

Photon Effects in Hg 1− x Cdx Te

Infrared detectors prepared from the alloy semiconductor Hg1−xCdxTe exhibit a family of relative response characteristics throughout the 1-μ to 14-μ spectral interval. Both photoconductive and photovoltaic effects are observed. The relative spectral responses shift to longer wavelengths with decreasing temperature. Photoconductive response time measurements at 77°K reveal values no greater than 10−7 sec. Detectors are limited by either thermal noise or current (1/f) noise, depending upon measurement frequency and magnitude of bias current.

Chapter 2 Principles of Uncooled Infrared Focal Plane Arrays

Publisher Summary This chapter describes the most widely used thermal detection mechanisms and provides an analysis of the fundamental performance limits common to all of them. It also discusses specific approaches to uncooled thermal imaging. The best way to design a high-performance uncooled thermal-imaging focal plane array based on a thermal detection mechanism is to begin with the design of the structure, for it is the structure that establishes the temperature fluctuation noise limit to the array performance. Furthermore, much of the array processing cost is structure-dependent. A monolithic thin-film approach based on Si technology appears to be the best. The approach described in this chapter is a simplified synopsis of an approach to designing uncooled IR arrays based on thermal detection mechanisms. The linear process described is in reality an iterative one, with choices made, evaluated, modified, re-evaluated, and so on. However, the overall approach presented in this chapter is believed by the author to be best.

Optical phase conjugation in Hg 1 − xCdxTe

We have observed phase-conjugate signals at 12, 77, and 295 K in n-type Hg1 - xCdxTe (x = 0.216-0.232) using degenerate four-wave mixing at 10.6 microm. The external power-reflection coefficient increases with the product of pump-power densities and saturates at 9%. The values of the third-order nonlinear susceptibility X(3) derived from these measurements agree with the theory of Wolff and Pearson [Phys. Rev. Lett. 17, 1015 (1966)] for X(3) that is due to conduction-band nonparabolicity.

Long wavelength photoeffects in mercury selenide, mercury telluride, and mercury telluride-cadmium telluride

Abstract Mercury selenide, mercury telluride, and mercury telluride-cadmium telluride are semiconductors which have been investigated as intrinsic infrared detecting materials. Mercury selenide and mercury telluride in the photoelectromagnetic-Nernst configuration exhibit spectral and frequency responses indicative of thermal rather than photon behavior. The signal is believed due to the Nernst thermal effect rather than the PEM photon effect. Mercury telluride-cadmium telluride exhibits photoconductivity at 77 °K and 4.2°K with a spectral response extending past 15 μ.

Solid‐State Infrared‐Wavelength Converter Employing High‐Quantum‐Efficiency Ge‐GaAs Heterojunction

An n‐p‐n heterojunction structure, formed by the epitaxial growth of n‐Ge on a p‐GaAs substrate having a diffused n‐GaAs region on the opposite face, has been employed to convert 1.5‐μ radiation incident on the n‐Ge face to 0.9‐μ radiation emitted from the n‐GaAs face. The internal quantum efficiency of the n‐Ge, p‐GaAs heterojunction is 0.62; the spectral response of the heterojunction is typical of photon effects in Ge. The internal wavelength conversion efficiency is 2.8×10−5, limited principally by the low electroluminescent quantum efficiency of the GaAs p‐n junction at low injection current densities.

Indium Antimonide Photoelectromagnetic Infrared Detector

The theory of operation, construction, and performance data of an infrared detector based upon the PEM effect in InSb are presented. Theoretical derivations of the spectral noise equivalent input, noise equivalent power, and responsivity are made which show the dependence of these figures of merit upon the electrical properties of the semiconductor, sample thickness, surface area, front and back surface recombination velocities, and magnetic induction. Performance of the detector operating at room temperature shows a spectral response extending to 7.5 microns and a response time of less than 1 microsecond. The noise equivalent input of a detector having a 0.71‐mm2 sensitive area has a minimum value at 6.6 microns of 6.7×10−10 w.

Bandgap-resonant optical phase conjugation in n-type Hg 1−x Cd x Te at 10.6 μm

We have observed phase-conjugate signals in n-type Hg(1-x) Cd(x) Te through bandgap-resonant degenerate fourwave mixing by using a chopped cw-CO(2) laser pump operating at 10.6 microm and ~1 W/cm(2). The observed signals are attributed to the strong resonant third-order nonlinearity [chi((3))] arising from the electron-hole pair production the pump laser. Our data translate into a value of chi((3))~3 x 10(-2) esu, which is in good agreement with that calculated using the model of Jain et al. [Appl. Phys. Lett. 35, 494 (1979)].

Observation of first Stokes, second Stokes, and anti‐Stokes radiation from a mercury cadmium telluride spin‐flip Raman laser

Single‐crystal Hg0.77Cd0.23Te has been employed in a spin‐flip Raman laser to generate first Stokes and anti‐Stokes radiation when pumped at 10.60 μm, and first Stokes, second Stokes, and anti‐Stokes radiation when pumped at 10.28 μm.