A solid-state high harmonic generation spectrometer with cryogenic cooling

TL;DR

This paper presents a cryogenically cooled solid-state high harmonic generation spectrometer enabling temperature-dependent studies of condensed matter, especially useful for exploring low-temperature phases in correlated materials.

Contribution

It introduces an advanced sHHG spectrometer with cryogenic cooling and in situ temperature control, expanding the capabilities of high harmonic spectroscopy at very low temperatures.

Findings

Sample temperature remains stable during high-intensity laser pulses.

Enables sHHG measurements down to a few Kelvin.

Facilitates studies of low-temperature phases in correlated materials.

Abstract

Solid-state high harmonic generation spectroscopy (sHHG) is a promising technique for studying electronic structure, symmetry, and dynamics in condensed matter systems. Here, we report on the implementation of an advanced sHHG spectrometer based on a vacuum chamber and closed-cycle helium cryostat. Using an in situ temperature probe, it is demonstrated that the sample interaction region retains cryogenic temperature during the application of high-intensity femtosecond laser pulses that generate high harmonics. The presented implementation opens the door for temperature-dependent sHHG measurements down to few Kelvin, which makes sHHG spectroscopy a new tool for studying phases of matter that emerge at low temperatures, which is particularly interesting for highly correlated materials.