High-speed terahertz time-domain spectroscopy of cyclotron resonance in pulsed magnetic field

D Molter,J Léotin,R Beigang,F Keilmann,M Goiran,T Weinland,S George,F Ellrich

doi:10.1364/oe.18.026163

Abstract

We present time-resolved cyclotron resonance spectra of holes in p-Ge measured during single magnetic field pulses by using a rapid-scanning, fiber-coupled terahertz time-domain spectroscopy system. The key component of the system is a rotating monolithic delay line featuring four helicoid mirror surfaces. It allows measurements of THz spectra at up to 250 Hz repetition rate. Here we show results taken at 150 Hz. In a single 900 ms measurement 135 cyclotron resonance spectra were recorded that fully agree with what is expected from literature.

Highlights

Terahertz (THz) measurements of cyclotron resonance (CR) in pulsed magnetic fields were so far mostly performed at fixed excitation frequencies from multiple microwave or laser line sources [1,2,3,4]
We present time-resolved cyclotron resonance spectra of holes in p-doped germanium (p-Ge) measured during single magnetic field pulses by using a rapidscanning, fiber-coupled terahertz time-domain spectroscopy system
Since femtosecond-laser-pumped THz time-domain spectroscopy (TDS) systems, in contrast, emit and detect broadband radiation, they offer the advantage of measuring continuous spectra as has been shown at constant magnetic field [5,6,7]

Summary

Introduction

Terahertz (THz) measurements of cyclotron resonance (CR) in pulsed magnetic fields were so far mostly performed at fixed excitation frequencies from multiple microwave or laser line sources [1,2,3,4]. Since femtosecond-laser-pumped THz time-domain spectroscopy (TDS) systems, in contrast, emit and detect broadband radiation, they offer the advantage of measuring continuous spectra as has been shown at constant magnetic field [5,6,7]. The disadvantage of these systems with pulsed magnetic fields has in the past been the long data acquisition time limited by slow mechanical scanning of the delay stage. To verify the applicability of our system, we present measurements of well-known cyclotron resonance of holes in p-doped germanium (p-Ge)

Methods

Results

Conclusion