A wave with a frequency of one terahertz has a wavelength of approximately 300 micrometers in free space. Consequently, the geometries of the structures required to operate in this frequency range are on this order of magnitude—and in most cases, even much smaller. To fabricate such samples, a technology is needed that enables the production of precise, particle-free, and high-resolution structures.

To this end, the research group has an ISO 5-class cleanroom at its disposal, which offers the following technological capabilities, among others:

• Structuring (optical lithography, electron beam and ion beam lithography)
• Coating processes (sputtering system, vapor deposition system)
• Chemical analysis and cleaning
• Structural analysis (profilometer, EDX)
• Microscopy (optical microscopes, STM, SEM, AFM)

The terahertz or submillimeter frequency range, roughly defined as approximately 300 GHz to 10 THz, has long been a gap in the electromagnetic spectrum. Developments over the past few decades have led to the creation of sophisticated systems that routinely operate in this frequency range and are of great use in fields such as astronomy and atmospheric sensor technology.

Until recently, however, this spectral range had resisted attempts to widely harness its potential for everyday applications. This gave rise to the term “THz gap,” which loosely describes the lack of suitable technologies to effectively bridge this transitional region between microwaves and optics—both of which are accessible via well-developed electronic and laser-based approaches.

Intensive research in recent years has opened up technological prospects for the development of widely applicable terahertz systems and identified a wide range of interdisciplinary application areas.