Two-dimensional electronic spectroscopy based on conventional optics and fast dual chopper data acquisition

Abstract

We report a new experimental scheme for two-dimensional electronic spectroscopy (2D-ES) based solely on conventional optical components and fast data acquisition. This is accomplished by working with two choppers synchronized to a 10 kHz repetition rate amplified laser system. We demonstrate how scattering and pump-probe contributions can be removed during 2D measurements and how the pump probe and local oscillator (LO) spectra can be generated and saved simultaneously with each population time measurement. As an example the 2D ES spectra for cresyl violet were obtained. The resulting 2D spectra show a significant oscillating signal during population evolution time which can be assigned to an intramolecular vibrational mode.

Optimizing sparse sampling for 2D electronic spectroscopy

“…At any given error level, the 2DvN representation requires a much smaller number of basis coefficients, thus it is more sparse than frequency space. exhibits pronounced oscillations in the crosspeaks as a function of the T delay, consistent with the literature [64][65][66][67] and originating from vibrational coherences. 68 Anticipating a decay of the signal for larger waiting times T and thus a greater sensitivity to the influence of experimental noise, we have chosen the 2D spectrum with the smallest signal amplitude at T = 300 fs as a reference data set and use this to optimize the sampling matrix.…”

Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution

“…13 It is based on a 10 kHz amplified Ti:sapphire laser pumping a NOPA which for these experiments was tuned to give sub 15 fs pulses centred at 660 nm with a bandwidth of 60 nm. The 2DES spectrometer was designed in the four beam boxcar geometry with the phase-stable beams generated by two beam splitters, and interpulse delays controlled by two precision delay stages, one mounted on a 0.1 µm resolution mechanical delay stage.…”

“…13 The samples were prepared by dissolving Chl a (Alpha Laboratories) in a variety of spectroscopic grade solvents. Chl a in solution is known to exhibit both self-quenching and the formation of complexes and aggregates, all of which may perturb the electronic spectra.…”

Resolving Vibrational from Electronic Coherences in Two-Dimensional Electronic Spectroscopy: The Role of the Laser Spectrum

“…As a result, 2D-ES recovers correlation maps between excitation and detection ðν 1 ;ν 3 Þ for each T. The 2D-ES signal arises from four-wave mixing pathways, which can be either rephasing (photon echo signal) or nonrephasing (free induction decay signal) according to their phase matching, and an equally weighted sum of both results in P ð3Þ ðν 1 ; T;ν 3 Þ [36,37]. Our experiment recovers complex-valued rephasing and nonrephasing maps independently [33,38].…”

“…[33]. 2D-ES requires determination of the excitation axis, which is possible by experimentally controlling the time delay between the first and the second field-matter interactions (labeled τ-the coherence time), the Fourier pair of which is the excitation wave numberν 1 .…”