Abstract-Uncooled Antenna-Coupled Microbolometer for Detection of Terahertz Radiation

 

Ivan Ryger, Peter Lobotka, Andreas Steiger, Stefan Chromik, Tibor Lalinsky, Zbyněk Raida, Kamil Pítra, Johann Zehetner, Marianna Spankova, Stefan Gazi, Michaela Sojkova, Gabriel Vanko 

https://link.springer.com/article/10.1007/s10762-021-00781-y

In this contribution, we describe the design, technology, and physical parameters of antenna-coupled microbolometer, used for broadband detection of terahertz electromagnetic spectrum. This microbolometer features an application of La0.67Sr0.33MnO3 layer grown on multilayered material stack ensuring lattice matching of the sensing LSMO layer to silicon. By virtue of bulk micromachining of silicon-on-insulator substrates, the sensing structure is built on thin suspended membrane to provide weak thermal link, increasing thermal response, thus sensitivity. Additionally, it helps suppressing excitation of in-plane guided surface modes that will otherwise deteriorate the antenna radiation diagram and affect the spectral responsivity of the sensor. Finally, the operation of sensor is demonstrated using a molecular laser setup at 762 GHz (and also 1.4 THz) emission line. The parameters of the said microbolometers are analyzed in terms of response and time constant. Optimal working temperature of the detectors is about 65 °C.

First international comparison of terahertz laser power measurements

Fig. 1:Happy faces after the work is done in the THz lab of PTB: John Lehman, Andreas Steiger, Qing Sun, and Yuqiang Deng (from the left to the right)

http://www.ptb.de/cms/en/service-seiten/news/scientific-news.html?tx_news_pi1%5Bnews%5D=5646&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Baction%5D=detail&tx_news_pi1%5Bday%5D=18&tx_news_pi1%5Bmonth%5D=5&tx_news_pi1%5Byear%5D=2015&cHash=89b2a5d102ff461587748802494e77d8

Measurements of terahertz (THz) power are important for a variety of applications for climate research, security and communication technology, medicine, and manufacturing. The first international comparison of THz laser power measurements took recently place at PTB in Berlin. Andreas Steiger hosted the comparison with the visiting scientists Yuqiang Deng and Qing Sun from the National Institute of Metrology (NIM) of China and John Lehman of the National Institute of Standards and Technology (NIST) who is presently visiting PTB as a Research Fellow of the Alexander von Humboldt Foundation of Germany. Measurements were carried out at two frequencies, 2.52 THz and 0.762 THz and at a power level of approximately 3 mW. The measurement results from each participant agreed very well with the reference value and to each other within the stated uncertainties.

The pilot comparison was undertaken in a relatively short period from May 4 to 8, 2015. Typically, such key comparisons may last years. Organized in a new manner, the participants met in Berlin to compare their standards at one place at one time. The measurement infrastructure such as the laser source and other instrumentation provided by PTB were critical to meeting the proposed schedule.

The comparison was performed via the spectral responsivity of the three different national THz standard detectors used according to the guidelines provided by the Consultative Committee on Photometry and Radiometry (CCPR). The results have still to be approved by the CCPR and will then be published for a larger community. The work represents the first key comparison ever undertaken in the far-infrared spectral region. It represents a milestone which will greatly benefit commercial development of instrumentation and sensors for remote sensing, THz imaging, high-speed telecommunications and time-domain spectroscopy.

Contact:

A. Steiger, 7.34, e-mail: Andreas.Steiger(at)ptb.de

Abstract-Traceable terahertz power measurement from 1 THz to 5 THz

Andreas Steiger, Mathias Kehrt, Christian Monte, and Ralf Müller »View Author Affiliations

The metrology institute in Germany, the Physikalisch-Technische Bundesanstalt (PTB), calibrates the spectral responsivity of THz detectors at 2.52 THz traceable to International System of Units. The Terahertz detector calibration facility is equipped with a standard detector calibrated against a cryogenic radiometer at this frequency. In order to extend this service to a broader spectral range in the THz region a new standard detector was developed. This detector is based on a commercial thermopile detector. Its absorber was modified and characterized by spectroscopic methods with respect to its absorptance and reflectance from 1 THz to 5 THz and at the wavelength of a helium-neon laser in the visible spectral range. This offers the possibility of tracing back the THz power responsivity scale to the more accurate responsivity scale in the visible spectral range and thereby to reduce the uncertainty of detector calibrations in the THz range significantly.

© 2013 OSA