Anti-stokes coherent

Figure 2. Experimental arrangement for generating many orders of anti-Stokes coherent emission in H2 gas [8].

COHERENT ANTI-STOKES RAMAN SPECTROSCOPY (CARS)... 

Our first example of aP - signal is coherent anti-Stokes Raman spectroscopy, or CARS. Fomially, tire emission signal into direction k= - k + k. has 48 Feynman diagrams that contribute. Flowever, if the... 

Knopp G, Pinkas I and Prior Y 2000 Two-dimensional time-delayed coherent anti-Stokes Raman spectroscopy and wavepacket dynamics of high ground-state vibrations J. Raman Spectrosc. 31 51... 

Oudar J-L, Smith R W and Shen Y R 1979 Polarization-sensitive coherent anti-Stokes Raman spectroscopy Appi. Rhys. Lett. 34 758-60... 

Joe T and Albrecht A C 1993 Femtosecond time-resolved coherent anti-Stokes Raman spectroscopy of liquid benzene a Kubo relaxation function analysis J. Chem. Phys. 99 3244-51... 

Gross L P, Trump D D, MacDonald B G and Switzer G L 1983 10-Hz coherent anti-Stokes Raman spectroscopy apparatus for turbulent combustion studies Rev. Sc/. Instrum. 54 563-71... 

Depending on the relative phase difference between these temis, one may observe various experimental spectra, as illustrated in figure Bl.5.14. This type of behaviour, while potentially a source of confiision, is familiar for other types of nonlinear spectroscopy, such as CARS (coherent anti-Stokes Raman scattering) [30. 31] and can be readily incorporated mto modelling of measured spectral features. 

New metliods appear regularly. The principal challenges to the ingenuity of the spectroscopist are availability of appropriate radiation sources, absorption or distortion of the radiation by the windows and other components of the high-pressure cells, and small samples. Lasers and synchrotron radiation sources are especially valuable, and use of beryllium gaskets for diamond-anvil cells will open new applications. Impulse-stimulated Brillouin [75], coherent anti-Stokes Raman [76, 77], picosecond kinetics of shocked materials [78], visible circular and x-ray magnetic circular dicliroism [79, 80] and x-ray emission [72] are but a few recent spectroscopic developments in static and dynamic high-pressure research. 

Coherent anti-Stokes Raman spectroscopy (CARS) [59] has also found utility in the detemiination of the internal state distributions of products of chemical reactions. This is one of several coherent Raman spectroscopies based on the... 

Valentin J J 1985 Coherent anti-Stokes spectroscopy Spectrometric Techniques vol 4, ed G A Vanasse (New York Academic) pp 1-62... 

Coherent anti-Stokes Raman scattering spectroscopy... 

Coherent anti-Stokes Raman scatttering, or CARS as it is usually known, depends on the general phenomenon of wave mixing, as occurs, for example, in a frequency doubling crystal (see Section 9.1.6). In that case three-wave mixing occurs involving two incident waves of wavenumber v and the outgoing wave of wavenumber 2v. 

The scattered radiation V3 is to high wavenumber of Vj (i.e. on the anti-Stokes side) and is coherent, unlike spontaneous Raman scattering hence the name CARS. As a consequence of the coherence of the scattering and the very high conversion efficiency to V3, the CARS radiation forms a collimated, laser-like beam. 

Figure 9.22 Experimental arrangement for coherent anti-Stokes Raman scattering...

CARS. See Coherent anti-Stokes Raman spectroscopy. 

An interesting variation of Raman spectroscopy is coherent anti-Stokes Raman spectroscopy (CARS) (99). If two laser beams, with angular frequencies CO and CO2 are combined in a material, and if cjj — is close to a Raman active frequency of the material, then radiation at a new frequency CJ3 = 2cJ2 — may be produced. Detection of this radiation can be used to characterize the material. Often one input frequency is fixed and the other frequency, from a tunable laser, varied until matches the Raman frequency. CARS has the capabiHty for measurements in flames, plasmas, and... 

Fig. 0.4. Experimental nitrogen Q-branch of coherent anti-Stokes Raman scattering spectrum (CARS) measured at 700 K and different pressures [14].

The best resolution of Q-branch rotational structure in a N2-Ar mixture was achieved by means of coherent anti-Stokes/Stokes Raman spectroscopy (CARS/CSRS) at very low pressures and temperatures (Fig. 0.4). A few components of such spectra obtained in [227] are shown in Fig. 5.9. A composition of well-resolved Lorentzian lines was compared in [227] with theoretical description of the spectrum based on the secular simplification. The line widths (5.55) are presented as... 

Bouche Th., Drier Th., Lange B., Wolfrum J., Franck E. U., Schilling W. Collisional narrowing and spectral shift in coherent anti-Stokes Raman spectra of molecular nitrogen up to 2500 bar and 700 K, Appl. Phys. B50, 527-33 (1990). 

Smirnov V. V., Fabelinskii V. I. Pressure-induced change of the shape and width of the coherent anti-Stokes light scattering spectrum of the V2 oscillations of acetylene. JETP Lett. 27, 123-5 (1978) [Pis ma ZhETP, 27, 131-4 (1978)]. 

Farrow R. L., Rahn L. A. Interpreting coherent anti-Stokes Raman spectra measured with multimode Nd YAG pump lasers, J. Opt. Soc. Am. B2, 903-7 (1985). 

Koszykowski M. L., Farrow R. L., Palmer R. E. Calculation of collisionally narrowed coherent anti-Stokes Raman spectroscopy spectra, Opt. Lett. 10, 478-80 (1985). 

CARS see coherent anti-Stokes/Stokes Raman spectroscopy centrifugal sudden (CS) approximation 155, 166... 

The present study demonstrates that the analytic calculation of hyperpolarizability dispersion coefficients provides an efficient alternative to the pointwise calculation of dispersion curves. The dispersion coefficients provide additional insight into non-linear optical properties and are transferable between the various optical processes, also to processes not investigated here as for example the ac-Kerr effect or coherent anti-Stokes Raman scattering (CARS), which depend on two independent laser frequencies and would be expensive to study with calculations ex-plictly frequency-dependent calculations. 

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