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MO: Fachverband Molekülphysik

MO 7: Femtosecond Spectroscopy I: Electronic 2D Spectroscopy (contributed for SYED in MO)

MO 7.3: Vortrag

Montag, 18. März 2013, 17:00–17:15, F 102

Pulse-Shaping-Based Two Dimensional Electronic Spectroscopy in a Modified Pump-Probe geometry: Applications to the Photosystem II Reaction Center — •Franklin Fuller, Daniel Wilcox, and Jennifer Ogilvie — University of Michigan, Ann Arbor, MI, USA

Two dimensional spectroscopy has been performed with pulse shapers in the pump probe geometry at both visible and infrared frequencies. The pulse shaped pump probe geometry affords many benefits, such as ease of alignment, lack of moving parts, and automatic global phasing. Also, the geometry lends itself to broad-band probing, which is key for deciphering the congested spectra of the photosystem II reaction center (PSII RC). However, since the method is not background free, the signal-to-noise ratio in the pump-probe geometry is limited compared to background-free approaches. We demonstrate a simple and low-cost modification to the pulse-shaped 2D setup which enables one to collect the signal in a background free manner. In the case of Qx band of PSII, where the transient extinction coefficient is 100 times weaker than the Qy band, we show that this modification in conjunction with a NOPA affords over an order of magnitude improvement in signal to noise compared to traditional white-light probing. Furthermore, we show that the technique may also be applied to standard pump-probe measurements to similar effect.