Time-domain terahertz spectrometer with 1-18 THz spectral coverage based on a Cr:ZnS oscillator

Abstract

Toward multi-octave spanning molecular spectroscopy, Cr:ZnS femtosecond oscillators are regarded among the most promising mid-infrared sources [1]. By employing nonlinear compression using a TiO<inf>2</inf> plate [2], these oscillators provide carrier-envelope-phase stable single-cycle pulses at 2.2 μm and support highly efficient spectral down-conversion to the 3-12 μm spectral range [3]. Further bandwidth extension, ultimately reaching the sub-terahertz regime, is expected to enhance the reliability of molecular identification through vibrational spectroscopy. However, there are few reports on far-infrared to terahertz generation based on 2-micron femtosecond oscillators [4]. In this study, we present, for the first time, broadband terahertz generation and detection based on optical rectification from a Cr:ZnS femtosecond oscillator.