Current science, 2009

Journal of Raman Spectroscopy, 2013

are highlighted in this review and reflect topics and advances at the frontier of Raman spectroscopy, a field that is expanding rapidly as a sensitive photonic probe of matter at the molecular level in an ever widening sphere of novel applications.

2015 Fotonica AEIT Italian Conference on Photonics Technologies, 2015

We give a detailed theoretical analysis of the simplest variant of femtosecond stimulated Raman spectroscopy, where a picosecond Raman pump pulse and a femtosecond Raman probe pulse are applied resonantly to a chromophore in thermal equilibrium in the ground electronic state. We demonstrate that this technique is capable of the detection of dephasing-free Raman-like lines revealing vibrational modes not only in the electronic ground state but also in the excited electronic state of the chromophore. The analytical results obtained with simplifying assumptions for the shape of the laser pulses are substantiated by numerical simulations with realistic laser pulses, employing the equation-of-motion phase-matching approach.

The Journal of chemical …, 2009

Scientific Reports, 2016

Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by...

Journal of the Optical Society of America B, 1985

We discuss a technique for nonlinear Raman spectroscopy that utilizes two orthogonally polarized, frequency-degenerate pump waves whose relative phase is modulated. A phase-modulated signal wave results from the mixing of the pump waves and a probe wave through the third-order, nonlinear susceptibility X 3 . Heterodyne detection of the signal wave yields signals linear in X3, permits measurement of both the real and the imaginary parts of X 3 , and routinely provides shot-noise-limited sensitivities. Expressions for signal voltages are derived and typical spectra quantitatively analyzed. Cf c) cc Ua +Q : H. We 0 C. U 0 C.) J U a) G. J. Rosasco and W. S. Hurst Vol. 2, No. 9/September 1985/J. Opt. Soc. Am. B 0 U, Q 0 c.) C) W an Ud M G.

Curr Sci India, 2008

2010

Femtosecond stimulated Raman spectroscopy (FSRS) is a new ultrafast spectroscopic technique that provides vibrational structural information with high temporal (50-fs) and spectral (10-cm −1) resolution. As a result of these unique capabilities, FSRS studies of chemical and biochemical reaction dynamics are expected to grow rapidly, giving previously unattainable insight into the structural dynamics of reactively evolving systems with atomic spatial and femtosecond temporal resolution. This review discusses the experimental and theoretical concepts behind FSRS, with an emphasis on the origins of its unique temporal and spectral capabilities. We illustrate these capabilities with vibrational studies of ultrafast electronic dynamics, as well as the direct structural observation of nonstationary vibrational wave-packet motion in small molecules and in complex biochemical reaction dynamics. Reaction coordinate: specific path on one or more potential energy surfaces that describes the geometric and electronic changes occurring in a chemical transformation

Applied Spectroscopy, 2003

Femtosecond stimulated Raman spectroscopy (FSRS) is a new technique that produces high-quality vibrational spectra free from background uorescen ce. FSRS combines a narrow-bandwidth picosecond Raman pump pulse with an ;80 fs continuum probe pulse to produce stimulated Raman spectra from the pump-induced gain in the probe spectrum. The high intensity of the Raman pump combined with the broad bandwidth of the probe produces high signalto-noise vibrational spectra with very short data acquisition tim es. FSRS spectra of standard solutions and solvents such as aqueous Na 2 SO 4 , aqueous KNO 3 , methanol, isopropanol, and cyclohexane are collected in seconds. Furthermore, stim ulated Raman spectra can be obtained using just a single pump-probe pulse pair that illuminates the sample for only ;1 ps. Fluorescence rejection is demonstrated by collecting FSRS spectra of dyes (rhodamine 6G, chlorophyll a, and DTTCI) with varying degrees of uorescence background and reso nance enhancement. The high signal-to-noise, short data acquisition time, uorescence rejection, and high spectral and temporal resolution of femtosecond stimulated Raman spectroscopy make it a valuable new vibrational spectro scopic technique.

Journal of Molecular Structure, 1990