Simple model of coherent anti‐Stokes Raman scattering signals generated by means of linearly chirped ultrashort Gaussian laser pulses. (24th March 2018)

• Record Type: Journal Article
• Authors: Marrocco, M.
• Other Names: Schmitt Michael guestEditor.; Popp Jürgen guestEditor.; Kiefer Johannes guestEditor.; Moger Julian guestEditor.
• Is Part Of: Journal of Raman spectroscopy. Volume 49:Number 7(2018)
• Page Start: 1109
• Page End: 1115
• Publication Date: 2018-03-24
• Subjects: coherent anti‐Stokes Raman scattering -- laser spectroscopy -- ultrafast laser physics; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.5373
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract: Time and frequency dependences of coherent anti‐Stokes Raman scattering (CARS) are here found analytically for the increasingly popular experimental approach where the Raman preparation and probing are realized by means of very short linearly chirped laser pulses. These are chosen with Gaussian lineshapes that, besides being rather common in ultrashort laser physics, guarantee full solution to the nonlinear scattering problem at hand. The solution appears rather simple in spite of the complications arising from the treatment of optical nonlinearities of different nature (dielectric susceptibility of the third order for the Raman medium and quadratic phases of three laser fields). The simplicity of the solution allows versatile applications that are here shown for different chirp effects in vibrational and purely rotational N2 CARS whose spectral complexity provides an excellent ground to test the model. The comparison with known experiments shows a good agreement except for some limitations imposed by deviations of the nonresonant CARS signal from the Gaussian structure assumed in the model. Abstract : Time and frequency dependences of coherent anti‐Stokes Raman signals are calculated analytically for linearly chirped ultrashort laser pulses of Gaussian profiles. Elaboration of signals is provided for N2 CARS that is typical in combustion thermometry. Simulated rotational and vibrational spectra reproduce published experimental results (see the figure that shows an example of ultrafast vibrational N2 CARS).