Laser polarization spectroscopy

Wieman, C. and Hansch, T.W. (1976). Doppler-free laser polarization spectroscopy, Phys. Rev. Lett., 36, 1170-1173. 

Fluorescence and stimulated emission on transitions (p = 0 -> p" > 0) lead to a fast rise of the population densities A (p") of high vibrational levels in the Sq state. This would result in a self-termination of the laser oscillation if these levels were not depopulated quickly enough by collisions. The relaxation of N(v") toward the thermal equilibrium population No(v") can again be probed by a weak visible probe laser. Polarization spectroscopy (Sect. 2.4) with femtosecond pulses allows one to separately determine the decay times tvib of population redistribution and the dephasing times [814]. 

R.E. Teets, F.V. Kowalski, W.T. HiU, N. Carlson, T.W. Hansch, Laser polarization spectroscopy, in Advances in laser Spectroscopy. SPIE Proc., vol. 113 (1977), p. 80 R. Teets, Laser polarisation spectroscopy. PhD thesis, Physics Department, Stanford University, 1978... 

M. Katar, S. Kasahara, W. Demtrbder, Y. Tamamitani, A. Doi, H. Kato Doppler-free laser polarization spectroscopy and optical-optical double resonances of a large molecule Naphthalene. J. Chem. Phys. 119, 3691 (2003)... 

Zircon belongs to the tetragonal system and is a positive uniaxial. The typical form shows the ill and the 110 planes. The two orientations selected for luminescence polarization study were the (110) plane, parallel to the basal section and the [100] row. In such cases the axis perpendicular to the (110) plane will be called X. The orientation notation is made according to the so-called Porto notation (Porto et al. 1956). The Xi(ZX2)Xi orientation means that the laser light entered parallel to the Xi axis of the crystal and is polarized in the Z direction, while the emission is collected along the Xi axis with X2 polarization. By polarization spectroscopy with a high spectral resolution (less then 0.1 nm) six lines are observed for the Dq- Fi transition of the Eu-II center instead of the maximum three allowed for an unique site (Fig. 5.12). In Z(XX)Z geometry which corresponds to observation of a-polarized luminescence we... 

A very new approach to improve the sensitivity of NMR spectroscopy is the injection of laser-polarized Xe isotopes into the sample volume of the NMR... 

Fig. 5. Schematic represntation of equipment for laser-polarized Xe in NMR spectroscopy. Reproduced with peimission from (J6). Copyright 1999 American Chemical Society.

Because of the limitations of NMR spectroscopy by the decrease of the signal-to-noise ratio at elevated temperatures, the application of laser-polarized Xe isotopes for enhancing the polarization of resonating nuclei may help to expand the accessible temperature range in the future. 

In the future, we can expect the development of novel experimental techniques in solid-state NMR spectroscopy for investigation of functioning catalysts. Important goals are (i) the enhancement of the sensitivity of solid-state NMR spectroscopy, for example, by a selective enhancement of the nuclear polarization taking advantage of laser-polarized xenon, (ii) increases in the temperature range accessible for the characterization of solid-catalyzed reactions, and (iii) the coupling of NMR spectroscopy with other techniques such as mass spectrometry. Furthermore, modern two-dimensional techniques of solid-state NMR spectroscopy such as MQMAS NMR spectroscopy will be applied to improve the resolution of the spectra. 

The authors of [297] have presented the most consistent classical approach for the description of the polarization of a molecular gas by a strong light wave. The basic and principal difference between the methods of polarization spectroscopy and laser probing of dichroism consists of the fact that polarization spectroscopy demands the application of monochromatic single-frequency radiation, whilst probing of dichroism is based on the employment of a broad spectral irradiation. 

Summary. X-ray line emissions from ultrashort high-intensity laser-produced plasma were studied in order to clarify the physics of energy transport associated with the generation of ultrashort X-ray pulses for use in various applications. This article reviews two topics. The first is the application of Ka spectroscopy to the study of energy transport in laser-produced plasma. The second topic is the application of X-ray polarization spectroscopy to measurements of the anisotropy of hot electrons generated with ultrashort high-intensity laser pulses. 

Kieffer JC, Matte JP, Chaker, Beaudoin Y, Chien CY, Coe S, Mourou G, Dubau J, Inal MK (1993) X-ray-line polarization spectroscopy in laser-produced plasmas. Phys Rev E 48 4648-4658... 

Inubushi Y, Nishimura H, Ochiai M, Fujioka S, Izawa S (2004) X-ray polarization spectroscopy for measurement of anisotropy of hot electrons generated with ultraintense laser pulse. Rev Sci Instrum 75 3699-3701... 

The seminal work of Marcus and Hush has had a significant impact on the development of PET. Pioneering efforts by Sutin, Hopfield, Jortner, and others established the connection between thermal electron transfer and photoelectron transfer [6]. This work set the stage for a notable series of experiments where laser flash spectroscopy [7], chemically induced nuclear polarization [8], resonance Raman spectroscopy [9], time-resolved microwave conductivity [10], and time-resolved photoacoustic calorimetry [11], to site only a few examples, have been successfully employed to chart the dynamics of PET in homogeneous solution, the solid-state, and organized assemblies. 

---