Reststrahlen effect

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The Reststrahlen effect (German: “residual rays”) is a reflectance phenomenon in which electromagnetic radiation within a narrow energy band cannot propagate within a given medium due to a change in refractive index concurrent with the specific absorbance band of the medium in question; this narrow energy band is termed the Reststrahlen band.

As a result of this inability to propagate, normally-incident Reststrahlen band radiation experiences strong-reflection or total-reflection from that medium.

The energies at which Reststrahlen bands occur vary and are particular to the individual compound.

Numerous physical attributes of a compound will have an effect on the appearance of the Reststrahlen band these include but are not limited to; phonon band-gap, particle/grain size, strongly absorbing compounds, compounds with optically opaque bands in the infrared.

Appearance[edit]

Reststrahlen bands manifest in diffuse reflectance infrared absorption spectra as complete band reversal, or in infrared emission spectra as a minima in emissivity.

Application[edit]

The Reststrahlen effect is used to investigate the properties of semiconductors, it is also used in geophysics and meteorology.

See also[edit]

References[edit]

  • Elachi, C. et al. (2006) Introduction to the physics and techniques of remote sensing. John Wiley and Sons.
  • Griffiths, P.R. (1983) Fourier transform infrared spectrometry. Science, 222, 297–302.
  • Goldberg, A. et al. (2003) Detection of buried land mines using a dual-band LWIR/LWIR QWIP focal plane array. Infrared Physics & Technology, 44 (5-6), 427-437.
  • Anderson, M. S. et al. (2005) Fourier transform infrared spectroscopy for Mars science. Rev. Sci. Instrum., 76 (3).