We report two-color two-dimensional Fourier transform electronic spectroscopy obtained using an acousto-optic pulse-shaper in a pump-probe geometry. The two-color setup will facilitate the study of energy transfer between electronic transitions that are widely separated in energy. We demonstrate the method at visible wavelengths on the laser dye LDS750 in acetonitrile. We discuss phase-cycling and polarization schemes to optimize the signal-to-noise ratio in the pump-probe geometry. We also demonstrate that phase-cycling can be used to separate rephasing and nonrephasing signal components.

Two-dimensional decay associated spectra 2C2DES Two-color two-dimensional electronic spectroscopy 2DES Two-dimensional electronic spectroscopy 2DIR Two-dimensional infrared spectroscopy 2PE Two-pulse photon echo BBO Beta-barium borate BChl Bacteriochlorophyll BRC Bacterial reaction center CCD Charge-collecting device CGS Common ground state Chl Chlorophyll CP Cross-peak CS Charge separation DAS Decay associated spectra DMSO Dimethyl sulfoxide DO Diffractive optic DSP Digital signal processor EET Excitation energy transfer ESM Exponential series method ESA Excited state absorption xiv ESE Excited state emission ET Energy transfer FRET Fluorescence resonance energy transfer GSB Ground state bleach LHCII Light-harvesting complex II LN Liquid nitrogen LO Local oscillator NMR Nuclear magnetic resonance NOPA Non-collinear optical parametric amplifier OD Optical density PC Prism compressor PERY N,N'-bis (2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylicdiimide Pheo Pheophytin PSI Photosystem I PSII Photosystem II RC D1D2-cyt.b559 reaction center complex SFG Sum frequency generation SHB Spectral hole burning SNR Signal-to-noise ratio SPM Self-phase modulation SVD Singular value decomposition TA Transient absorption TRF Time-resolved fluorescence ZAP-SPIDER Zero additional phase spectral interferometry for direct electric field reconstruction xv ABSTRACT Two-Dimensional Electronic Spectroscopy of the Photosystem II D1D2-cyt.b559

We develop the theoretical framework for calculating magnetic noise from conducting two-dimensional (2D) materials. We describe how local measurements of this noise can directly probe the wave-vector dependent transport properties of the material over a broad range of length scales, thus providing new insight into a range of correlated phenomena in 2D electronic systems. As an example , we demonstrate how transport in the hydrodynamic regime in an electronic system exhibits a unique signature in the magnetic noise profile that distinguishes it from diffusive and ballistic transport and how it can be used to measure the viscosity of the electronic fluid. We employ a Boltzmann approach in a two-time relaxation-time approximation to compute the conductivity of graphene and quantitatively illustrate these transport regimes and the experimental feasibility of observing them. Next, we discuss signatures of isolated impurities lodged inside the conducting 2D material. The noise near an impurity is found to be suppressed compared to the background by an amount that is directly proportional to the cross-section of electrons/holes scattering off of the impurity. We use these results to outline an experimental proposal to measure the temperature dependent level-shift and line-width of the resonance associated with an Anderson impurity.

We report simulations of the two-dimensional electronic spectroscopy of the Qy band of the D1-D2-Cyt b559 photosystem II reaction center at 77 K. We base the simulations on an existing Hamiltonian that was derived by simultaneous fitting to a wide range of linear spectroscopic measurements and described within modified Redfield theory. The model obtains reasonable agreement with most aspects of the two-dimensional spectra, including the overall peak shapes and excited state absorption features. It does not reproduce the rapid equilibration from high energy to low energy excitonic states evident by a strong cross-peak below the diagonal. We explore modifications to the model to incorporate new structural data and improve agreement with the two-dimensional spectra. We find that strengthening the system–bath coupling and lowering the degree of disorder significantly improves agreement with the cross-peak feature, while lessening agreement with the relative diagonal/antidiagonal width of the 2D spectra. We conclude that two-dimensional electronic spectroscopy provides a sensitive test of excitonic models of the photosystem II reaction center and discuss avenues for further refinement of such models.

We examine the effect that pulse chirp has on the shape of two- dimensional electronic spectra through calculations and experiments. For the calculations we use a model two electronic level system with a solvent interaction represented by a simple Gaussian correlation function and compare the resulting spectra to experiments carried out on an organic dye molecule (Rhodamine 800). Both calculations and experiments show that distortions due to chirp are most significant when the pulses used in the experiment have different amounts of chirp, introducing peak shape asymmetry that could be interpreted as spectrally dependent relaxation. When all pulses have similar chirp the distortions are reduced but still affect the anti-diagonal symmetry of the peak shapes and introduce negative features that could be interpreted as excited state absorption.