Detection in broadband pump‐probe spectroscopy systems based on birefringent wedges
Aula: Sala Marconi - Ore: 14.00
Via Trieste 17, Brescia
Seminar lecture in the framework of International doctoral school in Science
Paolo FRANCESCHINI, PhD student @Università Cattolica del Sacro Cuore and KU Leuven, will deliver a lecture.
Chairperson: Ph.D student Stefano DANESI
In the pump‐probe ultrafast spectroscopic technique, the maximum information about the excited‐state dynamics under study is obtained by using a broadband probe pulse. The preferable approach for the detection of the wavelength‐dependent differential transmission consists in simultaneous measurement of its different frequency components. In the case of high‐pulse‐energy amplified laser systems running at ~kHz rep. rate, parallel detection is typically accomplished by a multi‐channel line camera; unfortunately, for low‐energy laser oscillators running at ~MHz rep. rate, similar analyzers capable of single‐shot detection do not exist.
In this lecture I will introduce an innovative device, suitable for those systems operating in the MHz regime, in which, after the sample, the probe passes through a linear interferometer employing birefringent wedges that creates two phase‐locked delayed replicas of the pulse; after being demodulated by a lock‐in amplifier, their interferogram is Fourier transformed to provide the differential transmission of the spectrum.