Linearity of Air-Biased Coherent Detection for Terahertz Time-Domain Spectroscopy

Tianwu Wang, Krzysztof Iwaszczuk, Emil Astrup Wrisberg, Emil Vosmar Denning, Peter Uhd Jepsen

    Research output: Contribution to journalJournal articleResearchpeer-review


    The performance of air-biased coherent detection (ABCD) in a broadband two-color laser-induced air plasma system for terahertz time-domain spectroscopy (THz-TDS) has been investigated. Fundamental parameters of the ABCD detection, including signal-to-noise ratio (SNR), dynamic range (DR), and linearity of detection have been characterized. Moreover, the performance of a photomultiplier tube (PMT) and an avalanche photodiode (APD) as photodetector in the ABCD have been compared. We have observed nonlinear behavior of PMT detector, which leads to artificial gain factor in TDS spectroscopy. The APD turns out to have superior linearity and three times higher dynamic compared to the PMT.
    Original languageEnglish
    JournalJournal of Infrared, Millimeter and Terahertz Waves
    Issue number6
    Pages (from-to)592-604
    Publication statusPublished - 2016


    • Air plasma
    • Broadband THz spectroscopy
    • Infrared lasers
    • Photodetectors
    • THz-TDS
    • Laser produced plasmas
    • Laser pulses
    • Photomultipliers
    • Photons
    • Plasmons
    • Reflectometers
    • Signal to noise ratio
    • Spectrophotometers
    • Air plasmas
    • Avalanche Photo Diode (APD)
    • Coherent detection
    • Nonlinear behavior
    • Photomultiplier tube
    • Terahertz time domain spectroscopy
    • Thz spectroscopy
    • Terahertz spectroscopy


    Dive into the research topics of 'Linearity of Air-Biased Coherent Detection for Terahertz Time-Domain Spectroscopy'. Together they form a unique fingerprint.

    Cite this