Beat-frequency-resolved two-dimensional electronic spectroscopy: disentangling vibrational coherences in artificial fluorescent proteins with sub-10-fs visible laser pulses

Abstract

We perform a beat-frequency-resolved analysis for two-dimensional electronic spectroscopy using a high-speed and stable 2D electronic spectrometer and few-cycle visible laser pulses to disentangle the vibrational coherences in an artificial fluorescent protein. We develop a highly stable ultrashort light source that generates 5.3-fs visible pulses with a pulse energy of 4.7 µJ at a repetition rate of 10 kHz using multi-plate pulse compression and laser filamentation in a gas cell. The above-5.3-fs laser pulses together with a high-speed multichannel detector enable us to measure a series of 2D electronic spectra, which are resolved in terms of beat frequency related to vibrational coherence. We successfully extract the discrete vibrational peaks behind the inhomogeneous broadening in the absorption spectra and the vibrational quantum beats of the excited electronic state behind the strong incoherent population background in the typical 2D electronic spectra.

Sub-two-cycle intense pulse generation based on two-stage hollow-core fiber compression using an ytterbium amplifier

“…18) This limitation has been solved by using a helium-filled gas cell around the focus of laser pulses prior to a multi-plate section. 19) Multi-pass nonlinear pulse compression schemes have been demonstrated using solid 20,21) and gas 22) as nonlinear media to shorten a long pulses with relatively low pulse energy. Recently, the generation of 6.9 fs, 0.78 mJ pulses at 500 kHz has been achieved by using a silver mirror-based multi-pass cell.…”