Ultra‐Broadband and High‐Dynamic‐Range THz Time‐Domain Spectroscopy System Based on Organic Crystal Emitter and Detector in Transmission and Reflection Geometry. Issue 4 (17th February 2021)

• Record Type: Journal Article
• Authors: Puc, Uros; Bach, Tobias; Günter, Peter; Zgonik, Marko; Jazbinsek, Mojca
• Is Part Of: Advanced photonics research. Volume 2:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-17
• Subjects: DAST -- DSTMS -- organic crystals -- reflections -- spectroscopies -- terahertz -- transmissions; Photonics -- Periodicals; 621.36505
• DOI: 10.1002/adpr.202000098
• Languages: English
• ISSNs: 2699-9293

Abstract

Abstract : The terahertz range of the electromagnetic spectrum reveals important insights when studying material properties. An ultra‐broadband terahertz time‐domain spectroscopy system based on state‐of‐the‐art, high‐stability organic nonlinear optical crystals used as both THz wave generator and detector is presented. In transmission geometry, a broad spectrum exceeding 20 THz and a high dynamic range of more than 80 dB is achieved using a compact 100 MHz femtosecond laser working at telecom wavelength 1560 nm. In the normal‐incidence reflection geometry, a similar bandwidth with a dynamic range surpassing 60 dB is reported. The experimental results are supported by a complete theoretical model, which includes the pump pulse duration, THz phonon/vibrational modes of the organic crystals and optical/THz beam path optimizations. The effectiveness of the newly developed system is demonstrated by measuring pharmaceutical samples with distinct THz features in the ultra‐broadband THz range and by measuring narrow water vapor lines at a spectral resolution of 2.7 GHz (0.090 cm −1 ), resulting in an excellent accuracy with a frequency deviation of less than 0.05% from the reference values. Abstract : An ultra‐broadband terahertz time‐domain spectroscopy (THz TDS) system with organic‐crystal emitter and detector, exhibiting outstanding performance considering the bandwidth (up to 20 THz), peak dynamic range (more than 80 dB), and spectral resolution (below 3 GHz), is demonstrated.