Raman transitions - Quantiki | Quantum information wiki and portal. Raman spectroscopy is a spectroscopic technique used in condensed matter physics and chemistry to study vibrational, rotational, and other low-frequency modes in a system. In quantum computation, it is not only used for characterising physical systems, but to control their evolution by changing the population of atomic energy levels in a coherent manner.
It relies on inelastic scattering, or Raman scattering of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. When used for spectroscopy, Phonons or other excitations in the system are absorbed or emitted by the laser light, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the phonon modes in the system. Infrared spectroscopy yields similar, but complementary information. Raman spectroscopy has a stimulated version, analogous to stimulated emission, called stimulated Raman scattering. Basic theory Raman scattering red-shifted.
[physics/0008013] Negative Group Velocity. On the physical origins of the negative index of refraction. New J. Phys. 7 (2005) 213doi:10.1088/1367-2630/7/1/213PII: S1367-2630(05)97268-6 On the physical origins of the negative index of refraction David W Ward1,3, Keith A Nelson1 and Kevin J Webb2 1 Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA2 School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907-2035, USA 3 Author to whom any correspondence should be addressed.
Email: david@davidward.org Received 31 March 2005Published 7 October 2005 In 1968, Veselago [1] suggested that a material with a negative index of refraction would enjoy certain peculiar properties. In this paper, we explore the physical origins of the negative index of refraction. To illustrate how negative refraction might arise, consider Fermat's principle of least time [11] for the case of negative refractive index materials. The field radiated in the x-direction by a thin sheet of microscopic electric dipoles is where -direction. ). . . . References.
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