Terahertz Technology – Sources
Terahertz sources. Left: Diode lasers and photomixers for cw-terahertz generation. Right: Pulsed terahertz spectroscopy platform.
- Electronic systems: High power, ideal for terahertz imaging
- Optoelectronic systems: High bandwidth, ideal for spectroscopy
- Pulsed lasers: Fast measurements, broad spectrum
- cw lasers: Precisely tunable, highest spectral resolution
Optoelectronic terahertz generation is an expression for indirect methods, where near-infrared laser light illuminates a metal-semiconductor-metal structure, generating a photocurrent that becomes the source of a terahertz wave. Both pulsed and continuous-wave (cw) techniques have been realized, and both have their advantages and limitations. Pulsed terahertz radiation offers a higher bandwidth (typically 0.1 .. 5 THz) and permits very fast measurements – a spectrum can be acquired within milliseconds. On the other hand, the frequency resolution is limited to several GHz. Vice versa, a cw system features a somewhat lower bandwidth (typ. 0.1 .. 2 THz) and requires longer measurement times – acquiring a spectrum takes several minutes –, yet the frequency can be controlled with extreme precision (down to single MHz).
TOPTICA offers ultrafast fiber lasers and a new spectroscopy setup for pulsed terahertz generation, and DFB diode lasers for cw terahertz applications. Our Spectroscopy Extensions provides all required components to get an actual measurement started. Complete “TopSeller” configurations are available for some of the most common frequency-domain terahertz applications.