rus
Issue #6/2025
I.A.Glinskiy, D.S.Ponomarev, M.V.Maytama, R.A.Khabibullin
PORTABLE SOURCES OF TERAHERTZ RADIATION RANGING FROM 2 TO 5 THz: FROM LABORATORY SAMPLE TO COMMERCIAL DEVICE
PORTABLE SOURCES OF TERAHERTZ RADIATION RANGING FROM 2 TO 5 THz: FROM LABORATORY SAMPLE TO COMMERCIAL DEVICE
INTRODUCTION
For a long time, the electromagnetic area of spectrum from 60 to 150 micrometers (2–10 THz) remained poorly studied, which was related to the lack of radiation sources in this frequency range. The emergence in 2002 of the first quantum cascade laser (QCL), demonstrating generation at a frequency of about 4 THz, was revolutionary for exploring the terahertz range. The first samples of THz quantum cascade lasers operated at cryogenic temperatures, had peak powers in the range of a few microwatts, and were intended only for use in scientific laboratories. Over the past 20 years, the characteristics of THz quantum cascade lasers have significantly improved, and now these lasers are used to solve a wide range of fundamental and applied tasks [1–4]. From the perspective of practically significant tasks, THz sources based on quantum cascade lasers are in demand for gas spectroscopy aimed at detecting ultra-low concentrations of various substances [5–7], as well as in medicine and in non-destructive testing devices for the quality control of dielectric objects [8–10].
In recent years, THz radiation sources based on quantum cascade lasers have started to appear on the global market as a commercial product. In Russia, starting in 2024, the MIPT (Moscow Institute of Physics and Technology) is conducting research and development work on a THz source based on a quantum cascade laser with a Stirling refrigerator, with the support of the federal project "Development of domestic instrument engineering for civilian purposes for scientific research". Figure 1 schematically shows the structure of the device being developed called "Teralaser". The co-executor of this R&D project, the Department of Ultraviolet Semiconductor Electronics named after V.G.Mokerov at the Center for Advanced Microelectronics of the Kurchatov Institute, is developing a QCL crystal that is mounted on a heatsink.
The developed THz source is capable of forming a Gaussian beam with a narrow generation line at frequencies of 2–5 THz. The zone design of the laser can be developed in such a way that the generation frequency coincides with absorption lines of the studied object, for example, with the absorption lines of pollutant gases – carbon monoxide CO (1.607 THz), formaldehyde CH2O (2.390 THz), nitrogen oxide NO (3.0151 THz), ammonia NH3 (3.593 THz). The pulse power of the QCL exceeds 0.1 mW with pulse durations of 1 μs.
During the development of the "Teralaser", the idea was implemented to use compact Stirling-based refrigerators for cooling the QCL, with both water and air cooling systems. The cooling capacity of Stirling refrigerators allows maintaining a temperature of about 77 K with a thermal load of up to 15–30 W. The developed device "Teralaser" also includes a built-in quasi-optical focusing system, providing a directed and symmetric THz beam, which allowed achieving an angular divergence of the beam of less than 30°. The weight of the device is only 15 kg, and its dimensions are just 30 × 30 × 30 cm, making it easy to use both in the laboratory and in production (Fig.2).
In addition to the device itself, a power supply control unit for the solid-state laser (laser driver) has also been developed, which allows to set duration and amplitude of the voltage pulses (see Fig.3). To control the THz source, domestic software has been developed that enables operation of the Stirling refrigerator and the solid-state laser driver to be managed. The device can be interacted with via a computer using the developed software.
CONCLUSIONS
Thus, the developed THz source based on the QCL is a fully completed device that does not require the purchase of additional equipment for its operation, and allows it to be implemented in various fields of research and production.
ACKNOWLEDGEMENTS
Authors are grateful for the financial support of the Federal Project "Development of Domestic Civil Instrumentation for Scientific Research" (OKR "Teralaser"), as well as the state assignment of SRC "Kurchatov Institute" within the framework of the constituent part of the THz source (KCL)was developed.
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
For a long time, the electromagnetic area of spectrum from 60 to 150 micrometers (2–10 THz) remained poorly studied, which was related to the lack of radiation sources in this frequency range. The emergence in 2002 of the first quantum cascade laser (QCL), demonstrating generation at a frequency of about 4 THz, was revolutionary for exploring the terahertz range. The first samples of THz quantum cascade lasers operated at cryogenic temperatures, had peak powers in the range of a few microwatts, and were intended only for use in scientific laboratories. Over the past 20 years, the characteristics of THz quantum cascade lasers have significantly improved, and now these lasers are used to solve a wide range of fundamental and applied tasks [1–4]. From the perspective of practically significant tasks, THz sources based on quantum cascade lasers are in demand for gas spectroscopy aimed at detecting ultra-low concentrations of various substances [5–7], as well as in medicine and in non-destructive testing devices for the quality control of dielectric objects [8–10].
In recent years, THz radiation sources based on quantum cascade lasers have started to appear on the global market as a commercial product. In Russia, starting in 2024, the MIPT (Moscow Institute of Physics and Technology) is conducting research and development work on a THz source based on a quantum cascade laser with a Stirling refrigerator, with the support of the federal project "Development of domestic instrument engineering for civilian purposes for scientific research". Figure 1 schematically shows the structure of the device being developed called "Teralaser". The co-executor of this R&D project, the Department of Ultraviolet Semiconductor Electronics named after V.G.Mokerov at the Center for Advanced Microelectronics of the Kurchatov Institute, is developing a QCL crystal that is mounted on a heatsink.
The developed THz source is capable of forming a Gaussian beam with a narrow generation line at frequencies of 2–5 THz. The zone design of the laser can be developed in such a way that the generation frequency coincides with absorption lines of the studied object, for example, with the absorption lines of pollutant gases – carbon monoxide CO (1.607 THz), formaldehyde CH2O (2.390 THz), nitrogen oxide NO (3.0151 THz), ammonia NH3 (3.593 THz). The pulse power of the QCL exceeds 0.1 mW with pulse durations of 1 μs.
During the development of the "Teralaser", the idea was implemented to use compact Stirling-based refrigerators for cooling the QCL, with both water and air cooling systems. The cooling capacity of Stirling refrigerators allows maintaining a temperature of about 77 K with a thermal load of up to 15–30 W. The developed device "Teralaser" also includes a built-in quasi-optical focusing system, providing a directed and symmetric THz beam, which allowed achieving an angular divergence of the beam of less than 30°. The weight of the device is only 15 kg, and its dimensions are just 30 × 30 × 30 cm, making it easy to use both in the laboratory and in production (Fig.2).
In addition to the device itself, a power supply control unit for the solid-state laser (laser driver) has also been developed, which allows to set duration and amplitude of the voltage pulses (see Fig.3). To control the THz source, domestic software has been developed that enables operation of the Stirling refrigerator and the solid-state laser driver to be managed. The device can be interacted with via a computer using the developed software.
CONCLUSIONS
Thus, the developed THz source based on the QCL is a fully completed device that does not require the purchase of additional equipment for its operation, and allows it to be implemented in various fields of research and production.
ACKNOWLEDGEMENTS
Authors are grateful for the financial support of the Federal Project "Development of Domestic Civil Instrumentation for Scientific Research" (OKR "Teralaser"), as well as the state assignment of SRC "Kurchatov Institute" within the framework of the constituent part of the THz source (KCL)was developed.
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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