Two-dimensional electronic spectroscopy with a continuum probe

Abstract

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.

Energy transfer pathways in semiconducting carbon nanotubes revealed using two-dimensional white-light spectroscopy

“…There are many different spectrometer designs for collecting 2D spectra 18,[34][35][36][37][38][39][40][41][42] . Our spectrometer design, shown in Supplementary Fig.…”

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

“…The probe beam can be either an attenuated replica of the pump or a spectrally broader white light continuum. 29 The advantage of this scheme is that the signal is generated collinearly with the probe beam so that it is heterodyned with the probe itself and therefore automatically phased. This means that the absorptive component will be generated with no further need to phase the signal according to the projection slice theorem.…”

Tracking the primary photoconversion events in rhodopsins by ultrafast optical spectroscopy

“…Advantages of this configuration are its simplicity and the fact that it automatically measures absorptive 2DES spectra, which are the most direct to interpret. Collinear phase-locked pulses can be generated by a pulse shaper, such as a liquid crystal spatial light modulator, 62 an acousto-optic modulator, 61 an acoustooptic programmable dispersive filter 63 or alternatively a passive birefringent delay line. 64 …”