Molecular Physics seminar

Angle-Resolved Coherent Wave-Mixing using a 4 fs Ultra-Broad Bandwidth Laser

by Ian Mercer (UCD Dublin, Department of Physics, Ireland)

FA31 ()


We will overview the recently introduced technique in coherent multi-dimensional spectroscopy of Angle-Resolved Coherent (ARC) wave-mixing. We will discuss recent results with ARC wave mixing using 4 fs light pulses derived from a laser source that spans 550–1000 nm. We believe this to be the shortest pulse duration used to date in coherent multi-dimensional spectroscopy. This marriage of technique and light source will permit new investigations of the interplay between energy transfers and quantum superposition states spanning 8200 cm−1. We applied this configuration to measurements on the photosynthetic low light (LL) complex from Rhodopseudomonas palustris in solution at ambient temperature. We observe bi-exponential population dynamics for energy transfer across 5500 cm−1 (0.65 eV), which we attribute to energy transfer from the Qx transition of bacteriochlorophylls to the B850 pigment of the complex. For the first time to the best of our knowledge, we demonstrate that ARC maps can be recorded using a single laser pulse. A proposed configuration for ARC Raman could in future provide for a dynamic mapping of molecular structure by mapping vibration-vibration couplings in two-dimensions. We will discuss some recent results in working towards this using this 4 fs light source. I. P. Mercer, T. Witting, T. Driver, R. J. Cogdell, J. P. Marangos, and J. W. G. Tisch, Optics Letters Vol. 42, Issue 4, pp. 859-862 (2017). I. P. Mercer, Phys. Rev. A 82, 043406 (2010). I. P. Mercer, T. Witting, T. Driver, R. J. Cogdell, J. P. Marangos, and J. W. G. Tisch, Phys. Rev. Lett. 102, 057402 (2009).