Optical measurement of the temporal delay between two ultra-short and focussed laser pluses

Abstract

Temporal overlapping of ultra-short and focussed laser pulses is a particularly challenging task, as this timescale lies orders of magnitude below the typical range of fast electronic devices. Here we present an optical technique that allows for the measurement of the temporal delay between two focussed and ultra-short laser pulses. This method is virtually applicable to any focussing geometry and relative intensity of the two lasers. Experimental implementation of this technique provides excellent quantitative agreement with theoretical expectations. The proposed technique will prove highly beneficial for high-power multiple-beam laser experiments.

A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

“…The images moving from left to right demonstrate the changing pattern when the delay is changed in steps of 2T 0 where T 0 is the laser pulse duration i.e., 45 fs. As can be seen the number of fringes seen in the horizontal axis falls as synchronisation is approached [38].…”

“…In order to achieve synchronisation on the fs timescale, an interferometric technique was developed that allows one to synchronise pulses with a high level of precision (details of which can be found at [38]). As an example, we plot in Fig.…”

“…Details in the text and in Ref. [38] The images show the position on the CCD chip in the vertical axis against the wavelengths mapped to the CDD chip. The images moving from left to right demonstrate the changing pattern when the delay is changed in steps of 2T 0 where T 0 is the laser pulse duration i.e., 45 fs.…”

Quantum electrodynamics experiments with colliding petawatt laser pulses

“…Therefore additional, micrometre-size optimization of the path length of the two focused PW laser pulses needs to be implemented. Experimentally, the femtosecond-level synchronization of the focused femtosecond pulses is measured and optimized in situ, in the focal spot of the two colliding pulses [25] . In order to perform the measurement, the energy of the colliding pulses is attenuated.…”

Radiation reaction studies in an all-optical set-up: experimental limitations

“…One has then to rely on optical methods that exploit the fastest probes available in the experiment, i.e., the laser itself. Recently, Corvan et al [42] have developed a simple optical technique, based on spectral interferometry, that is able to synchronise the two lasers (i.e., the scattering laser and the one driving the wakefield acceleration) with a resolution of the order of a few tens of fs. This technique was successfully applied to generate high-brightness and high-energy γ-ray beams resulting from Compton scattering of the electrons in the laser beam [15].…”