Optical shifts

Vollmer, F. Braun, D. Libchaber, A. Khoshsima, M. Teraoka, I. Arnold, S., Protein detection by optical shift of a resonant microcavity, Appl. Phys. Lett. 2002, 80, 4057 4059... 

Stable, cubic phase, PbS nanoparticles were prepared in a polymeric matrix by exchanging Pb + ions in an ethylene - 15% methacrylic acid copolymer followed by reaction with H2S [91]. The size of the PbS nanoparticles was dependent on the initial concentration of Pb + ions with diameters ranging from 13 to 125 A. The smallest particles (13 A) are reported to be molecular in nature and exhibit discrete absorption bands in their optical spectra. Two theoretical models, which take into account the effect of nonparabolicity, were proposed in order to explain the observed size-dependent optical shifts for PbS nanocrystallites. The authors reported that the effective mass approximation fails for PbS nanocrystallites. 

Optical shifts [233-239] as well as mass changes [236, 45] produced by water sorption, are used to determine the packing density of thin films. 

Assay of Deoxyribonuclease. Hydrolysis of DNA is followed by methods similar to those used with RNA. Another unexpected optical shift occurs, an increase in density at 260 mu occurs on hydrolysis this may be caused by rupture of hydrogen bonds involving the bases. 

The molecular constants that describe the stnicture of a molecule can be measured using many optical teclmiques described in section A3.5.1 as long as the resolution is sufficient to separate the rovibrational states [110. 111 and 112]. Absorption spectroscopy is difficult with ions in the gas phase, hence many ion species have been first studied by matrix isolation methods [113], in which the IR spectrum is observed for ions trapped witliin a frozen noble gas on a liquid-helium cooled surface. The measured frequencies may be shifted as much as 1 % from gas phase values because of the weak interaction witli the matrix. 

The preparation of the reflecting silver layers for MBI deserves special attention, since it affects the optical properties of the mirrors. Another important issue is the optical phase change [ ] at the mica/silver interface, which is responsible for a wavelength-dependent shift of all FECOs. The phase change is a fimction of silver layer thickness, T, especially for T < 40 mn [54]. The roughness of the silver layers can also have an effect on the resolution of the distance measurement [59, 60]. 

Figure Cl.4.5. Population modulation as the atom moves through the standing wave in the Tin-periD-lin one dimensional optical molasses. The population lags the light shift such that kinetic is converted to potential energy then dissipated into the empty modes of the radiation field by spontaneous emission (after 1171).

Figure C 1.4.8. (a) An energy level diagram showing the shift of Zeeman levels as the atom moves away from the z = 0 axis. The atom encounters a restoring force in either direction from counteriDropagating light beams, (b) A typical optical arrangement for implementation of a magneto-optical trap.

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