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Terahertz laboratory

View into the THz laboratory with several experiments for example on the left a the telescope of a THz security scanner and in the center a laser system for SOFIA.

The terahertz(THz) laboratory is a multi-purpose laboratory for the development of THz technology needed, for example, in GREAT, upGREAT as well as in security applications. The strength and uniqueness of the laboratory are rooted in its wide range of detectors, spectrometers, and radiation sources. The entire THz spectral region (1mm to 30µm or 0.3 – 10THz) is covered by state-of-the-art detectors, spectrometers, and radiation sources. The following list gives an overview of the most important THz equipment:

1. Detectors

• cryogenic photoconductive detectors (Ge:Cu, Ge:Ga, stressed Ge:Ga, 30-210µm, NEP10-13W/Hz1/2
• cryogenic silicon bolometer (1mm -50µm, NEP10-14W/Hz1/2)
• cryogenic InSb hot-electron bolometer (1mm - 200µm, NEP10-12W/Hz1/2)
• cryogenic, ultra-fast (rise time < 35ps) superconducting NbN hot-electron bolometer
• Schottky diodes (500µm – 100µm, noise temperature 2000 - 10000K)
• room-temperature Golay cell detectors (1mm – 10µm, NEP10-10W/Hz1/2)
• room-temperature pyroelectric detectors (1mm - 30µm, NEP10-8W/Hz1/2)

2. Spectrometers

• grating spectrometer (Czerny-Turner) for 50-500µm
• Fourier transform spectrometer (1µm – 1000µm)
• polarizing (Martin-Puplett) Fourier spectrometer (100µm - 5mm)
• time-domain spectrometer (100µm - 1mm)

3. Radiation sources

• several backward-wave oscillators (0.15 – 0.45THz and 0.5 – 0.75THz, each up to 10mW power)
• several multiplied microwave source (0.3-0.35THz, 0.77-0.87THz, up to 1mW power)
• black-body radiators (10µm to 1mm)
• The THz lasers of the laser laboratory can also be used in the terahertz laboratory.

Besides these instruments, all laboratory equipment necessary for THz research and development is available (4K cryogenic facilities, cryostats for 77K, 4K, and 0.3K, ultra-high vacuum equipment, 6GHz real-time oscilloscope, 50GHz sampling oscilloscope, low-noise amplifiers, etc.). This laboratory is in particular used by the PhD students (in total eight) of the Helmholtz Research School on Security Technologies. The facilities are also available for external users in the frame of joint projects.