The time-resolved optical Kerr responses of several simple molecular liquids are probed with 65-fs laser pulses. Four dynamically distinct responses associated with the nonlinear susceptibility are observed in every liquid that possesses a permanent anisotropic polarizability. A simple model that specifically includes inertial effects provides an excellent description of the entire temporal profile of the Kerr signal of each liquid investigated. The role of coherent-coupling effects in the interpretation of optical Kerr data is outlined both experimentally and theoretically. >

Femtosecond optical Kerr studies on the origin of the nonlinear responses in simple liquids

High intensity Raman interactions

A review of the salient features of five coherent Raman techniques is given, including typical spectra produced by each technique. The resonant and nonresonant signal contributions in the monochromatic plane wave limit are calculated for: (1) Coherent AntiStokes Raman Spectroscopy(CARS); (2) a polarization technique referred to as ASTERISK; (3) Raman-induced Kerr-effect Spectroscopy(RIKES); (4) Optically Heterodyned RIKES (OHD-RIKES); (5) Stimulated Raman Spectroscopy (SRS). The relevant noise contribution to each of these techniques is developed within the framework of a comparative signal-to-noise analysis, and realistic detection limits are discussed. The OHD-RIKES technique is selected as the most viable of the coherent Raman techniques which satisfies the following criteria: (A) suppression of nonresonant background signals and enhanced signal-to-noise ratio; (b) simplicity of operation and interpretation of results. This is the first known application of optical heterodyne detection and optimization to coherent Raman spectroscopy, and the principles developed are generally applicable to all forms of third-order nonlinear spectroscopu.

Coherent Raman spectroscopy

Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast nonlinear optical technique that provides vibrational structural information with high temporal (sub-50 fs) precision and high spectral (10 cm(-1) ) resolution. Since the first full demonstration of its capabilities ≈15 years ago, FSRS has evolved into a mature technique, giving deep insights into chemical and biochemical reaction dynamics that would be inaccessible with any other technique. It is now being routinely applied to virtually all possible photochemical reactions and systems spanning from single molecules in solution to thin films, bulk crystals and macromolecular proteins. This review starts with an historic overview and discusses the theoretical and experimental concepts behind this technology. Emphasis is put on the current state-of-the-art experimental realization and several variations of FSRS that have been developed. The unique capabilities of FSRS are illustrated through a comprehensive presentation of experiments to date followed by prospects.

https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10.1002/cphc.201600331

Femtosecond Stimulated Raman Spectroscopy

Combustion diagnostics by laser Raman and fluorescence techniques

A new effect is demonstrated in which a laser pulse can be made to induce a Kerr effect only at Raman-shifted frequencies. This permitted the observation of a Raman spectrum with a single dye-laser pulse. The pulse power required is a small fraction of that required to produce stimulated instabilities. The spectral information emerges in a coherent beam, phase matching is not necessary, and spectra can be obtained at any scattering angle.

M. D. Levenson

Papers

Raman-Induced Kerr Effect

Measurement of the diamagnetic Zeeman shift of potassium S and D Rydberg states

The raman induced kerr effect and related phenomena

Oscillation Properties of Anisotropic Lasers