ROHM has developed a 2^nd Generation terahertz (THz) wave oscillation device usingsemiconductorelements known as Resonant Tunneling Diodes (RTDs). ROHM is making the device available via theRTD-EVK-G2 Terahertz Wave Device Evaluation Kit, which includes a sample device, cable, andevaluation board. The kit enables companies and research institutions to evaluate THz wave oscillation anddetection in a compact development environment.

Occupying the frequency region between radio waves and light, terahertz waves combine the penetrating properties of radio waves with the straight-line propagation oflight. Because they exhibitunique absorption characteristicsforpolymers, moisture, and other substances, they are expected to be used in non-destructive testingwithout ionizing radiation, medical and healthcare applications, and high-resolutionradar sensing. However,conventional terahertz systemsrequire large equipment and high implementation costs,making it difficult for new companies and research institutions to enter the fieldor pursue commercialization.

Since the late 2000s, ROHM has engaged in joint research with the Institute of Science Tokyo, OsakaUniversity, and many other universities and research institutions to develop THz wave oscillation anddetection devices using RTDs. In 2024, ROHM began offering samples of 1^st Generation products, achievingsubstantial downsizing and cost reduction compared with conventional methods.

To address the growing demand for improved signal quality in application development, ROHM has now developed a2^ndGenerationterahertz waveoscillationdevice.The devicemaintains the same compact 0.5 × 0.5mm chip size as the 1^st Generation product whileadopting an internal structure that enables higher output power. As a result, output power has been increasedto approximately 4 times that of the 1^stGeneration product, reaching a maximum of 40µW. The higher output power improves the detectability of THz waves after transmission through or reflection fromtarget objects–making the device well suited for applications such as sensing and imaging that require high signal quality.

The device is mounted in the same 4.0 × 4.3mm PLCC package, maintaining the industry’s smallest* footprint.This enables evaluation environments to be built even in space-constrained settings. In addition, compared withother THz generation methods, the RTD approach generates less heat and consumes less power, reducing application development load at both companies and research institutions

Sales of the RTD-EVK-G2 evaluation kit, which includes samples of the 2^nd Generation waveoscillation device, are planned to begin in August2026 at $3,300 per set (excluding tax). By enabling evaluation at a lower cost than other methods, the kitsupports the development of a wide range of applications, including non-destructive testing; imaging andsensing in the medical and healthcare sectors; material identification; and moisture detection. ROHM willalso continue sales of 1^st Generation devices for applications that prioritize low power consumption. Forfurther information, please contact a sales representative or visit the contact page on ROHM’s website. Purchase of the evaluation kit requires signing a non-disclosure agreement (NDA) with ROHM.

Going forward, ROHM will continue to expand the possibilities for THz wave application development andcontribute to the early commercializationand real-world implementation of terahertz technology, accelerating its deployment across a broad range of industries.

Professor Safumi Suzuki, Laboratory for Future Interdisciplinary Research of Science andTechnology, Institute of Integrated Research, Institute of Science Tokyo

“Terahertz waves are expected to be applied in a wide range of fields, including non-destructive testing,imaging and sensing, and wireless communications. At the same time, commercialization continues to facemajor challenges, such as the need for large-scale equipment and high implementation costs.

The RTD terahertz wave device developed through many years of joint research with ROHM is compact,power saving, and does not require cooling. It can also be introduced at low cost, helping companies andresearch institutions beginterahertz wave research.

With the launch of the 2^nd Generation device featuring significantly improved oscillation output, I expectdevelopment of applications requiring higher signal quality to accelerate.”

Ken Nakahara, General Manager of ROHM Research & Development Center, ROHMCo., Ltd.

“With the launch of RTD-EVK-G2, we expect to make another major step forward toward the practicalimplementation of terahertz technology.

Feedback from users of the 1^stGeneration device revealed strong demand forhigher-output devices. With this 2^nd Generation product, we have succeeded in increasingoscillation outputto approximately 4 times that of the 1^stGeneration device while maintaining a compact size, bringing uscloser to meeting those needs.

Terahertz technology is steadily progressingtoward real-world implementation. ROHM will continueworking together with customers, partners, universities, research institutions, and government agencies tosupport the development of terahertz wave applications and contribute to the realization of a sustainablesociety.”

Support Information

ROHM is committed to supporting terahertz wave research and application development and offers avariety of support materials.

Combining the RTD-EVK-G2 Terahertz Wave Device Evaluation Kit with measurement tools such asAnalog Discovery 3™ from Digilent (along with a computer and software) allows users toeasily evaluate THz waveoscillation and detection. Both the device and evaluation board are compact, making it possible to build aresearch and development environment even in limited spaces. For more information, please contact asales representative or visit the contact page on ROHM’s website.

Note: Analog Discovery 3™ is a trademark or registered trademark of Digilent, Inc

Professor Safumi Suzuki Profile

Doctor of Engineering, Professor at the Laboratory for Future Interdisciplinary Research of Science and

Technology, Institute of Integrated Research, Institute of Science Tokyo.His research focuses onthe development of terahertz wave devices using Resonant Tunneling Diodes (RTDs).

• Career

March 2009     :Completed a doctoral program at the Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology

April 2009        :Assistant Professor, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology

April 2014        : Associate Professor, Faculty of Engineering, Tokyo Institute of Technology

August 2024    :Professor, Laboratory for Future Interdisciplinary Research of Science and Technology, Institute of Innovative Research, Tokyo Institute of Technology

October 2024  : Professor,Laboratory for Future Interdisciplinary Research of Science and Technology, Institute of Integrated Research, Institute of Science Tokyo

Terminology

Resonant Tunneling Diode (RTD)

A semiconductor device used as a terahertz-wave source that offers advantages such as compact size, low power consumption, and room-temperature oscillation. Following extensive research and development with various universities and research institutions, ROHM has successfully achieved in-house production of RTD devices capable of efficient terahertz wave oscillation and detection.

PLCC

Short for Plastic Leaded Chip Carrier, a type of IC package used for semiconductor integrated circuits.

Other THz generation methods

Conventional methods for generating terahertz waves include ‘frequency multiplication,’ which converts an electrical signal into higher-order harmonic frequencies, and ‘photomixing,’where two laser beams of different wavelengths are combined in a photomixer to generate a terahertz signal at their difference frequency. While effective, both approaches typically require costly,medium- to large-scale equipment, limiting their practicality for compact, cost-sensitive applications.