Exact expressions for thermal contrast detected with thermal and quantum detectors

Seán M. Stewart, R. Barry Johnson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


The detected thermal contrast is a recently defined figure of merit introduced to describe the overall performance of a detector detecting radiation from a thermal source. We examine the detected thermal contrast for the case where the target emissivity can be assumed to be a function of the temperature and independent of the wavelength within a narrow wavelength interval of interest. Exact expressions are developed to evaluate the thermal contrast detected by both thermal and quantum detectors for focal-plane radiation detecting instruments. Expressions for the thermal contrast of a blackbody, an intrinsic radiative quantity of a body independent of the detection process, and simplified expressions for the detected thermal contrast for target emissivities which are well approximated by the grey body approximation are also given. It is found the contribution in the detected thermal contrast consists of two terms. The first results from changes occurring in the emissivity of a target with temperature while the second results from purely radiative processes. The size of the detected thermal contrast is found to be similar for the two detector types within typical infrared wavelength intervals of interest, contradicting a result previously reported in the literature. The exact results are presented in terms of a polylogarithmic formulation of the problem and extend a number of approximation schemes that have been proposed and developed in the past.

Original languageEnglish
Title of host publicationElectro-Optical and Infrared Systems
Subtitle of host publicationTechnology and Applications XI
EditorsDavid A. Huckridge, Reinhard Ebert
ISBN (Electronic)9781628413120
Publication statusPublished - Jan 1 2014
EventElectro-Optical and Infrared Systems: Technology and Applications XI - Amsterdam, Netherlands
Duration: Sep 23 2014Sep 24 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherElectro-Optical and Infrared Systems: Technology and Applications XI


  • Blackbody radiation
  • Detectors
  • Emissivity
  • Polylogarithms
  • Radiometry
  • Thermal contrast

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Exact expressions for thermal contrast detected with thermal and quantum detectors'. Together they form a unique fingerprint.

Cite this