Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor
1
Institute of Applied Electrodynamics and Telecommunications, Vilnius University, LT-10257 Vilnius, Lithuania
2
Research Group on Logistics and Defense Technology Management, General Jonas Žemaitis Military Academy of Lithuania, LT-10322 Vilnius, Lithuania
3
CENTERA Laboratory, Institute of High Pressure Physics PAS, 01-142 Warsaw, Poland
4
CEZAMAT, Warsaw Technical University, 02-822 Warsaw, Poland
*
Authors to whom correspondence should be addressed.
Appl. Sci. 2021, 11(1), 412; https://doi.org/10.3390/app11010412
Received: 30 November 2020
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Revised: 24 December 2020
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Accepted: 29 December 2020
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Published: 4 January 2021
(This article belongs to the Special Issue THz Spectroscopy: Basic Science and Application)
Over the last two decades, photomixer-based continuous wave systems developed into versatile and practical tools for terahertz (THz) spectroscopy. The high responsivity to the THz field amplitude of photomixer-based systems is predetermined by the homodyne detection principle that allows the system to have high sensitivity. Here, we show that the advantages of homodyne detection can be exploited with broadband power detectors combined with two photomixer sources. For this, we employ a THz detector based on a complementary metal-oxide-semiconductor field-effect transistor and a broadband bow-tie antenna (TeraFET). At 500 GHz and an effective noise bandwidth of 1 Hz, the response from one photomixer-based THz source resulted in an about 43 dB signal-to-noise ratio (SNR). We demonstrate that by employing a homodyne detection system by overlaying the radiation from two photomixers, the SNR can reach up to 70 dB at the same frequency with an integration time 100 ms. The improvement in SNR and the spectroscopic evidence for water vapor lines demonstrated up to 2.2 THz allow us to conclude that these detectors can be successfully used in practical continuous wave THz spectrometry systems.
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Keywords:
THz power detector; terahertz detector; broadband antenna; field-effect transistor; homodyne detection; terahertz spectroscopy
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MDPI and ACS Style
Ikamas, K.; But, D.B.; Lisauskas, A. Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor. Appl. Sci. 2021, 11, 412. https://doi.org/10.3390/app11010412
AMA Style
Ikamas K, But DB, Lisauskas A. Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor. Applied Sciences. 2021; 11(1):412. https://doi.org/10.3390/app11010412
Chicago/Turabian StyleIkamas, Kęstutis, Dmytro B. But, and Alvydas Lisauskas. 2021. "Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor" Applied Sciences 11, no. 1: 412. https://doi.org/10.3390/app11010412
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