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Transient measurement of phononic states with covariance-based stochastic spectroscopy
preprintposted on 2023-01-12, 14:33 authored by G. Sparapassi, S. M. Cavaletto, J. Tollerud, A. Montanaro, F. Glerean, A. Marciniak, F. Giusti, S. Mukamel, D. Fausti
We present a novel approach to transient Raman spectroscopy, which combines stochastic probe pulses and a covariance-based detection to measure stimulated Raman signals in alpha-quartz. A coherent broadband pump is used to simultaneously impulsively excite a range of different phonon modes, and the phase, amplitude, and energy of each mode are independently recovered as a function of the pump-probe delay by a noisy-probe and covariance-based analysis. Our experimental results and the associated theoretical description demonstrate the feasibility of 2D-Raman experiments based on the stochastic probe schemes, with new capabilities not available in equivalent mean-value-based 2D-Raman techniques. This work unlocks the gate for nonlinear spectroscopies to capitalize on the information hidden within the noise and overlooked by a mean-value analysis.