Riede, Aaron Christopher (2022). Fourier Transform Four-Wave Mixing Spectroscopy with Femtosecond Single-Shot Interferometry. (Thesis). Universität Bern, Bern
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Abstract
This thesis presents a novel approach to Fourier transform (FT) four-wave mixing (FWM) spectroscopy that renounces to implement costly and effortful means for suppression of phase fluctuations and delay control. It bases on the fact, that phase fluctuations arise from processes like mechanical vibrations of optical components, which are accumulated throughout the integration time of the detection system. However, in a pulsed laser experiment, the effective integration time is given by the pulse length and not the electronics of the detector, if data are collected on a single-shot basis. As a consequence, with a femtosecond laser system, it is possible to reduce the effective integration time by many orders of magnitude, which enables to run interferometric experiments without a loss of phase information even in the presence of phase fluctuations. Besides the concept and a proof of principle for single-shot interferometry (SSI), I present a new approach to adaptive pulse shaping by using a prism as a dispersing element and discuss its benefits and drawbacks on the basis of ray tracing simulation results. Transient grating FROG traces of broad-band visible pulses in the Fourier limit (8fs FWHM) show the compression capability of chirped mirrors in combination with thin fused silica wedge pairs. In the last chapter, two methods to vary the delay between the excitation pulses in an FT FWM experiment are analyzed and compared. One of them bases on a purposeful induction of mechanical noise to the system, which in conventional experiments is expected to lead to a complete loss of signal. Finally, I show the outcomes of an FT FWM spectroscopy experiment where analysis methods, which are unique to SSI, are tested on experimental data. Indeed, a strong improvement of the signal strength, gives evidence on the superior performance of SSI with respect to conventional acquisition schemes.
| Item Type: | Thesis |
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| Dissertation Type: | Single |
| Date of Defense: | 4 February 2022 |
| Subjects: | 500 Science > 530 Physics |
| Institute / Center: | 08 Faculty of Science > Institute of Applied Physics |
| Depositing User: | Hammer Igor |
| Date Deposited: | 22 Feb 2022 11:57 |
| Last Modified: | 22 Feb 2022 12:03 |
| URI: | https://boristheses.unibe.ch/id/eprint/3340 |
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