Delay modulation with a glass chopper in pump-probe experiments

Abstract

A delay modulator, made of glass plates rotating in a pump beam, is applied to measure time-resolved rates of transient processes in a pump-probe experimental setup. Glass plates modulate both delay and beam power. The contribution from the power modulation is subtracted by using a scaled-down measurement made with metal chopper blades. Delay modulation results obtained with this procedure are consistent with the derivative in delay of the usual power modulation and can show a larger signal to noise ratio.

Magnetic entropy dynamics in ultrafast demagnetization

“…A constant a 0 converts PD intensity to LIA voltage units and depends on PD and LIA settings. As for delay modulation [8], R 1 is proportional to the derivative ∂F ∂P , which depends on delay τ through the variable temperatures T e,s,l (τ ). Delay scans show a peak within 1 ps (figure 1(b)) from fast electron processes in ∂F/∂P convoluted with the pumpprobe cross-correlation (pp) corr = P probe (τ )P 0 .…”