Infrared Absorption in Crystals Term Paper by scribbler

Infrared Absorption in Crystals
A review of the research on infrared absorption enhancement in photonic crystals.
# 153349 | 1,706 words | 11 sources | APA | 2013 | US
Published on May 23, 2013 in Computer and Technology (Technology) , Physics (General)

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The paper explores the research on the use of infrared spectral imaging using photonic crystals and explains how the optical spectra of crystals are dependent upon their structure to determine their absorption properties. The paper discusses one of the most lucrative areas of development that is the use of photonic crystals in photodetectors and reviews the research on their development. The paper also notes that at present, the focus of research has been on the individual crystals and matrices of single compounds, however, research into multiple compound crystals will provide many avenues for research and development in the future.

Infrared Absorption in Crystals
Infrared Absorption in Photonic Crystals

From the Paper:

"The optical spectra of crystals are dependent upon their structure. They contain bands of varying frequency. Some of these bands are broad and some are narrow. Some are uniform over a large portion of the crystal. In the IR region, some bands exist that are associated with the transition between fluctuating energy levels that are a result of vibrational motions of the individual particles that comprise the crystal. These vibrational motions are accompanied by changes in the dipole moment at which point a photon is absorbed and a phonon is created. In a perfect crystal, these creations would be uniform. However, few, if any real perfect crystals exist. Crystals, rather natural or manmade have defects in their structure. These defects cause localized changes in vibration. When light interacts with lattice vibrations, it changes the polarity of the crystal as well. The combination of different vibrations throughout the crystal is much like a fingerprint that can be used to identify the crystal.
"Infrared absorption occurs using various types of mechanisms. H. Fan classified these mechanisms in 1956, as they applied to semiconductors. These classifications are still used today. The first is intrinsic absorption that is associated with electron excitation across the energy gap. The second is due to the presence of free carriers. The third is absorption due to impurities or lattice effects. The fourth classification is absorption associated with lattice vibration. Fan also explored the effects of temperature and carrier density."

Sample of Sources Used:

  • Berreman, D. 1963. Infrared Absorption at Longitudinal Optic Frequency in Cubic Crystal Films. Physics Review. 130 (6): 2193-2198.
  • Fan, H. 1956. Infra-red Absorption in Semiconductors. Rep. Prog. Phys. 19: 107
  • Kim. T., Warrender, J. and Aziz, M. 2006. Strong sub-band-gap infrared absorption in silicon supersaturated with sulfur. Applied Physics Letters 88, 241902 _2006_. Available [6 April 2011].
  • Livingston, E. and Zuzak, K. 2008. Patent application title: Characterization of a Near-Infrared Laparoscopic Hyperspectral Imaging System for Minimally Invasive Surgery. Available [6 April 2011].
  • MEMC Corporation. 2011. Measurement of Interstitial Oxygen in Silicon Ingots. Available [6 April 2011].

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APA Format

Infrared Absorption in Crystals (2013, May 23) Retrieved September 18, 2020, from

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