RIKEN scientists have developed a compact handheld device that utilizes the terahertz band of the electromagnetic spectrum to perform non-destructive “X-ray” imaging without harmful radiation. Through optimization techniques and the use of specific materials, they have successfully increased the power output of terahertz waves and reduced the size of the device. This breakthrough technology holds promise for a wide range of applications, including non-destructive imaging and quantum research. Collaborations with industry partners are already underway.
The terahertz band, situated between microwaves and infrared light, has been largely overlooked despite its potential. Terahertz waves offer exciting possibilities, as they can penetrate and provide insight into materials similar to X-rays, but without the harmful effects of ionizing radiation.
However, the development of terahertz technologies has been challenging due to the difficulty of adapting microwave or visible-light technologies to the terahertz range while maintaining practical sizes and power outputs.
To generate terahertz waves, researchers have explored different approaches, such as developing electrical devices to produce higher-frequency microwaves or converting shorter, higher-frequency waves of infrared light using nonlinear crystals.
At the RIKEN Center for Advanced Photonics, the focus has been on the latter approach—converting the output of an infrared laser into terahertz waves. Traditionally, generating powerful terahertz waves with this method required large lasers, limiting the applicability of terahertz technology in real-world scenarios where portable devices for on-site analysis would be more valuable.
In their quest to develop handheld terahertz wave sources for industry and fundamental research, the Tera-Photonics Research Team, led by Hiroaki Minamide, made significant progress. They discovered that by using sub-nanosecond laser pulses instead of longer ones, they could enhance the terahertz wave power output by six orders of magnitude—from 200 milliwatts to 100 kilowatts. Moreover, they achieved this powerful emission in a device that was only one meter square, considerably smaller than previous terahertz devices that occupied entire rooms.
To further reduce the device’s size, the team replaced the bulk lithium niobate crystal with a thin, artificially structured lithium niobate crystal known as a periodically poled lithium niobate (PPLN) crystal. This substitution, previously used in the visible-light region, enabled the development of a handheld device due to its higher light conversion efficiency.
During their experimentation with PPLN crystals, the researchers encountered unexpected behavior. Instead of detecting terahertz waves directly, they discovered that the interaction between light and the PPLN crystal’s structure caused the waves to be generated at the rear of the crystal. By adjusting the crystal’s rotation, they could tune the frequency of the terahertz waves produced. This breakthrough allowed them to create a palm-sized prototype with high conversion efficiency and ample power.
In addition to advancements in device miniaturization and power output, the researchers explored the quantum aspects of their work. They achieved cascade oscillation in backward terahertz-wave parametric oscillation and successfully detected ultraweak terahertz waves, which were 1,000 times more sensitive than conventional detectors. These quantum findings open new possibilities for terahertz-based research and applications, including quantum photon conversion and the exploration of quantum entanglement.
Complementing their highly miniaturized, high-power terahertz wave systems, recent advancements in compact photonic lasers have further enhanced the capabilities of RIKEN’s devices. With collaborations with industry partners such as Ricoh, Topcon, Mitsubishi Electric, and Hamamatsu Photonics, the team aims to develop non-destructive testing applications and terahertz-wave spectroscopy equipment.
The potential applications of terahertz waves are extensive. They can be used in security systems for detecting concealed objects, such as plastic guns behind glass surfaces that scatter light. Terahertz waves can also identify the chemical composition of substances through characteristic absorption patterns, enabling applications in airport security, analysis of historic artwork, and the evaluation of industrial paint and coatings without causing damage. By gaining a better understanding of material interactions and degradation through non-destructive technologies, processes can be optimized in real-time, leading to improved efficiency, extended lifespan of structures, and significant economic and environmental benefits.
Overall, RIKEN’s handheld terahertz device represents a major advancement in safe and portable “X-ray” imaging, with tremendous potential for various fields, from industrial applications to quantum research.
Table of Contents
Frequently Asked Questions (FAQs) about terahertz imaging
What is the handheld terahertz device developed by RIKEN?
The handheld terahertz device developed by RIKEN is a compact device that utilizes the terahertz band of the electromagnetic spectrum for non-destructive “X-ray” imaging without harmful radiation. It offers portable and safe solutions for imaging various objects and materials.
How does the terahertz device work?
The terahertz device works by converting the output of an infrared laser into terahertz waves using specific materials such as lithium niobate crystals. The device generates terahertz waves that can penetrate and provide imaging capabilities similar to X-rays, but without the harmful ionizing radiation.
What are the potential applications of the terahertz device?
The terahertz device has a wide range of potential applications. It can be used for non-destructive imaging in various industries, such as analyzing industrial paint, outer coatings, and pharmaceutical tablets. It can also be used for security purposes to detect concealed objects. Furthermore, terahertz waves can reveal the chemical composition of substances, making it useful in fields like airport security and analyzing historic artworks.
How is the terahertz device different from traditional X-ray imaging?
The terahertz device offers a radiation-free imaging alternative to traditional X-ray imaging. While traditional X-rays use ionizing radiation, which can be harmful, terahertz waves have much lower frequencies and energies, making them safer for imaging purposes. The terahertz device provides similar imaging capabilities without the associated health risks.
What are the advantages of the handheld terahertz device?
The handheld terahertz device offers several advantages. It is compact and portable, allowing for on-site and real-time analysis. It provides non-destructive imaging, enabling the evaluation of materials and structures without causing damage. Additionally, it offers a safe and radiation-free alternative to traditional X-ray imaging methods.
Are there any collaborations related to the terahertz device?
Yes, RIKEN has collaborations with several industry partners specializing in electronics, optics, and photonics. Companies such as Ricoh, Topcon, Mitsubishi Electric, and Hamamatsu Photonics are involved in joint research to develop non-destructive testing applications and terahertz-wave spectroscopy equipment, further expanding the potential of the terahertz device.
More about terahertz imaging
- RIKEN Center for Advanced Photonics: Official Website
- Journal of the Optical Society of America B: Research Paper
- Journal of Infrared, Millimeter, and Terahertz Waves: Research Paper
- Scientific Reports: Research Paper
- 2021 Conference on Lasers and Electro-Optics (CLEO): Conference Paper
5 comments
as an art enthusiast, the idea of using terahertz waves to analyze historic artworks is mind-blowing. it could help preserve and understand art in a whole new way. im looking forward to seeing how this technology develops.
terahertz waves are the future! its great that they found a way to use them for imaging. this could revolutionize so many industries from security to art analysis. im excited to see what other applications they come up with.
the quantum research aspect is fascinating! quantum entanglement and photon conversion opens up a whole new world of possibilities. who knows what breakthroughs they will achieve in the future. science is amazing!
collaborations with industry partners are crucial for real-world applications. it’s great to see companies like Ricoh, Topcon, Mitsubishi Electric, and Hamamatsu Photonics getting involved. together, they can push the boundaries of terahertz technology and bring it to the market faster.
wow this is amazin! finally, a device that can xray things without any dangerous radiation! its sooo coool that they can miniaturize it and make it portable. i hope they can make it even smaller in the future.