Terahertz Amplifiers: Powering the Future of Ultra-Fast Technology

The terahertz (THz) frequency range, which ranges from 0.1 to 10 THz, has long been known as the "terahertz gap." Historically, this band was beyond the capability of traditional electronics and below the scope of photonics. However, as the world demands much faster wireless connectivity, advanced imaging, and high-resolution spectroscopy, the gap is rapidly declining. A key component in this transformation? Terahertz amplifiers.

What Are Terahertz Amplifiers?

Terahertz amplifiers are devices that amplify weak signals in the THz frequency range. Their principal role, like that of RF or microwave amplifiers, is to boost the magnitude of a signal while retaining its original characteristics. Developing efficient and compact amplifiers at THz frequencies, on the other hand, involves distinct scientific and technical hurdles due to the extremely short wavelengths and rapid oscillations.

 A team of researchers lead by Professor Hyong-Ryeol Park from UNIST's Department of Physics has developed a technique capable of amplifying THz waves by more than 30,000 times. This innovation, when associated with artificial intelligence (AI) based on physical models, has the potential to transform the commercialization of 6G communication frequencies.

In 2015, Xiaobing Mei and team from Northrop Grumman Corporation, Redondo Beach, CA 90278 USA reported the successful development of first ever THz MMIC amplifier utilizing 25-nm InP HEMT process illustrating amplification at 1 THz with 9-dB measured gain at 1 THz. HEMTs and HBTs can be used to make solid state THz amplifiers. Graphene and other 2D materials based transistors can also be adopted in developing THz amplifiers. Vacuum electronic devices such as travelling wave tubes can also be incorporated in THz amplifiers.

 Challenges in THz Amplifier Design

While the prospects are exciting, the path ahead is far from simple. Here are a few major hurdles:

1.      Material Limitations

2.      Manufacturing Precision

3.      Low Gain and Efficiency

4.      Material Limitations

The Road Ahead

The future of THz amplifiers is strongly tied to the evolution of computing, sensing and communications. As research continues to break down technological and physical barriers, we can expect THz amplifiers to become smaller, more efficient, and more widely adopted. The real-world uses of THz amplification are expected to be significant, ranging from assisting your phone in downloading a 4K movie in a matter of seconds to using X-ray-free tumor detection.