9-13 July 2012
Development of refractive delay stages for application in two-dimensional electronic spectroscopy
Presented by Mr. David VAN DER WESTHUIZEN on 12 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track C - Photonics
Two-dimensional spectroscopy is a powerful tool for probing the intermolecular interactions between different transitions of complex molecules or aggregates. It is based on a four-wave mixing technique which involves irradiation of a sample by a sequence of three ultrashort laser pulses, propagating in a phase-matched box geometry, resulting in the generation of a third-order signal that is spatially isolated from the excitation pulses. We present a useful method for controlling the excitation-pulse temporal sequence. Wavelength tunability of the excitation pulses in the visible range is realized by means of a 1 kHz Ti:Sapphire femtosecond laser system and a noncollinear optical parametric amplifier (NOPA). Frequency-resolved optical gating (FROG) is used to characterize these pulses at the sample position. The time delays between the excitation pulses are introduced with subwavelength accuracy by means of glass wedge-based delay stages. Precise calibration of these time delays was achieved using spectral interferometry and the results are reported here.
Professor Heinrich Schwoerer, email@example.com, Stellenbosch University