Multidimensional spectroscopy with a single broadband phase-shaped laser pulse

Abstract

We calculate the frequency-dispersed nonlinear transmission signal of a phase-shaped visible pulse to fourth order in the field. Two phase profiles, a phase-step and phase-pulse, are considered. Two dimensional signals obtained by varying the detected frequency and phase parameters are presented for a three electronic band model system. We demonstrate how two-photon and stimulated Raman resonances can be manipulated by the phase profile and sign, and selected quantum pathways can be suppressed.

Nonlinear synthesis of complex laser waveforms at remote distances

“…The results unambiguously show the possibility of explicitly tailoring the output of laser filaments in air to a priori arbitrary waveforms. Potential applications range from selective standoff detection [4,[16][17][18][19][20][21][23][24][25][26][27]] to lightning control [44], atmospheric water condensation [45], and radiative forcing modulation [46]. Similar techniques could in principle be applied to any other remote application.…”

“…Active remote sensing, including standoff detection of explosives or harmful molecular agents, greatly benefits from non-linear interactions induced by ultrashort high intensity lasers. In particular, coherent Raman spectroscopy [4,[16][17][18][19][20][21][22], multi-photon excited fluorescence [23][24][25], and even atmospheric lasing [26][27][28][29] require a precise and stable spatiotemporal waveform at a defined distance. A particularly perturbation-sensitive strategy is the discrimination of almost identical molecules using coherently controlled multiphoton fluorescence [25,[30][31][32][33][34], like optimal dynamic discrimination (ODD).…”

Developments in Structural Chemistry from the Viewpoint of a Solid‐state Chemist: A Review Prompted by the Sixtieth Anniversary of Professor Jack Dunitz's Research Group in the ETH, Zurich

“…By recording a tilt series of such spectrum images, 4D “spectrum tomograms” produce spectral (hence chemical) information at every real space voxel. As in multidimensional spectroscopy, where there have been rapidly improving spatial, spectral, and temporal resolutions, so also is the case in multidimensional EM (which is designated MDEM). Figure illustrates both the essence and the potential structural power of MDEM.…”

Stimulated Emission Enhancement Using Shaped Pulses

“…34,35 Under direct resonance with a transition, a phase step has been used on isolated atoms and diatomics, detecting the resonant features as the phase step is scanned within the bandwidth of the excitation pulse. 27,36−38 There is only one case when the transmitted laser and resulting third-order polarization has been analyzed theoretically when using a phase step, 39 and that study was inspired by the results being presented here. We chose Indocyanine Green, also known as IR125, or Cardiogreen for our experiments, the same molecule used by Bardeen et al 17 IR125 contains two 1,1-dimethylbenzo[e]indole moieties connected by a seven-carbon conjugated polyene chain and has been studied extensively because of its low toxicity and fast elimination, making it ideal for in vivo fluorescent imaging and photodynamic therapy.…”

“…Here we explore stimulated emission resulting from the third-order polarization of cyanine dye molecules in solution when using a spectral phase step function. Two-photon transition control has been particularly successful when using a phase step because of constructive interference occurring at twice the frequency corresponding to the position of the phase step; this control has been reported for atoms as well as large organic molecules. − The similarity between two-photon excitation and coherent anti-Stokes Raman scattering (CARS) led to a phase step being used to enhance CARS signals. , Under direct resonance with a transition, a phase step has been used on isolated atoms and diatomics, detecting the resonant features as the phase step is scanned within the bandwidth of the excitation pulse. ,− There is only one case when the transmitted laser and resulting third-order polarization has been analyzed theoretically when using a phase step, and that study was inspired by the results being presented here.…”