Time-resolved nonlinear optical spectroscopy of perovskites.

Ultrafast decay of optical phonons has been studied in wide-bandgap BaSnO3 and SrTiO3 perovskites using nonlinear spectroscopy with 120 femtosecond time resolution. The coherent Raman mode excitations have been selected and traced with tunable optical pulses. Decay of symmetry forbidden modes of vibrations have been detected directly in time. Phonon decay rates for the main LO- and TO- phonon modes have been found to be within 1.36-1.78 ps-1 and are explained in terms of parametric phonon interactions and pure dephasing mechanisms in the materials that are of interest in microelectronic applications.

Femtosecond coherent Raman system with >75†dB dynamic range for probing vibration modes across 250-2400†cm-1.

We report on the design and performance of a time-resolved Coherent Raman spectroscopy system with time resolution of better than 120 fs. The coherent transients can be traced with more than 75 dB dynamic range while accessing and probing Raman active modes across a 250-2400 cm-1 frequency. The system delivers an equivalent spectral resolution of better than 0.1 cm-1 regarding line bandwidth parameters for probed Raman resonances.