Optical-pump terahertz-probe spectroscopy in high magnetic fields with kHz single-shot detection

TL;DR

This paper presents a rapid, single-shot optical-pump THz-probe spectroscopy method in high magnetic fields, enabling efficient measurement of nonequilibrium systems and demonstrating B-field dependent carrier dynamics in silicon.

Contribution

The authors introduce a kHz single-shot detection technique for OPTP spectroscopy in high magnetic fields, significantly reducing data acquisition time and expanding experimental capabilities.

Findings

Successful measurement of THz signals up to 9 T magnetic field.

Observation of B-dependent carrier relaxation in silicon.

Demonstration of high-speed, efficient data collection with linear array detectors.

Abstract

We demonstrate optical pump/THz probe (OPTP) spectroscopy with a variable external magnetic field (0-9 T) in which the time-dependent THz signal is measured by echelon-based single-shot detection at a 1 kHz repetition rate. The method reduces data acquisition times by more than an order of magnitude compared to conventional electro-optic sampling using a scanning delay stage. The approach illustrates the wide applicability of the single-shot measurement approach to nonequilibrium systems that are studied through OPTP spectroscopy, especially in cases where parameters such as magnetic field strength (B) or other experimental parameters are varied. We demonstrate the capabilities of our measurement by performing cyclotron resonance experiments in bulk silicon, where we observe B-field dependent carrier relaxation and distinct relaxation rates for different carrier types. We use a pair of economical linear array detectors to measure 500 time points on each shot, offering equivalent performance to camera-based detection with possibilities for higher repetition rates.