Experimental routines used as diagnostics modes.
To minimise the probe noise in single wavelength absorption experiments, the measurement is run without pump pulse and the probe beams are adjusted to hit the photodiode detectors in an optimal way. The noise level of consecutively measured points can then be optimised. The overlap between pump and probe beams can be optimised in a similar manner with the pump beam at positive delay times. To facilitate these diagnostics, the delay line movements can be turned off. To characterise and optimise pulse widths, auto- and cross-correlation experiments can be used. In sweep mode, auto-correlation traces can be measured, fit to a gaussian, and displayed together with the pulse width once per second (see fig).
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