TR-OS (R&T)

This setup for Time-Resolved Optical Spectroscopy (TR-OS) provides the opportunity to simultaneously measure the reflectivity and the transmittivity of the sample under scrutiny. Hence, it is particularly well-suited for transparent samples like thin films. Broadband detection in the visible to near-IR spectral range is achieved thanks to three Silicon linear array detectors, that sample the sample reflectivity, the sample transmittivity and a reference spectrum in the interval 400-1000 nm (corresponding to 1.2-3.1 eV). The pump is at 800 nm (1.55 eV). The setup also offers a tunable pump from an OPA, that can be set in the visible range in the interval 550-700 nm.

Figure: Simultaneously-acquired maps of the differential reflectivity (ΔR/R) and transmittivity (ΔT/T) of a WSe2 three-layer film, excited at 800 nm and collected at room temperature. The spectral profiles for ΔR/R and ΔT/T at time-zero are also displayed. The fact that they don’t sum to zero suggests that the sample absorption is modified by photoexcitation.