An achromatic pump-probe setup for broadband, few-cycle ultrafast spectroscopy in quantum materials

Emmanuel B Amuah; Allan S Johnson; Simon E Wall

doi:10.1063/5.0066760

An achromatic pump-probe setup for broadband, few-cycle ultrafast spectroscopy in quantum materials

Rev Sci Instrum. 2021 Oct 1;92(10):103003. doi: 10.1063/5.0066760.

Authors

Emmanuel B Amuah¹, Allan S Johnson¹, Simon E Wall¹

Affiliation

¹ ICFO-The Institute of Photonics Sciences, The Barcelona Institute of Science and Technology, Castelldefels, 08860 Barcelona, Spain.

PMID: 34717375
DOI: 10.1063/5.0066760

Abstract

In this work, we present an achromatic pump-probe setup covering the visible (VIS) to near-infrared (NIR) wavelength regions (500-3000 nm) for few-cycle pulses. Both the pump and probe arms can work either in the VIS or the NIR wavelength regions, making our setup suitable for multi-color, broadband pump-probe measurements. In particular, our setup minimizes time-smearing due to the phase front curvature, an aspect of ultrafast spectroscopy that has been missing from previous works and allowing us to achieve sub-20-fs temporal resolution. We demonstrate the capabilities of our setup by performing measurements on Pr_0.5Ca_1.5MnO₄. We pump and probe in both wavelength regions with a range of pump fluences and demonstrate how the observed dynamics depend strongly on the probe wavelength. Furthermore, the observation of a 16.5 THz phonon demonstrates the high temporal resolution of the setup.