Features
- Low temperature (LT) grown GaBiAs dipole structure
- Optimized for lasers with 1030 nm and shorter wavelength (cost effective)
- Wide spectral range 0.2-5 THz
- Build-in hemispherical high-resistivity silicon lens
Applications
- THz time domain spectroscopy
- THz imaging
- Optical pump – THz probe spectroscopy
THz emitter
THz emitter from LT GaBiAs epitaxial layer has on its surface a coplanar Hertzian dipole type antenna structure with a width of 70 µm, the width of the photosensitive gap is 20 µm. GaBiAs layer is mesa-et ched in order to achieve high dark resistance and to simplify the laser beam alignment. High photosensitivity of the material allows to use for the excitation very low average power generated by, e.g., femtosecond fiberlasers. The efficiencyof the optical to THz power conversion reaching 0.0007 is larger than for other photoconductive THz devices.
Average THz power as a function on the bias on GaBiAs emitter measured by the Golay cell
THz Detector
THz detectors manufactured from newly developed GaBiAs epitaxial layers can be used for in TDS systems activated by 1060 nm and shorter wavelength laser pulses. High electron mobility (~5000 cm2/Vs) in the layer guaranties excellent sensitivity of the device; due to the shorter than 0.5 ps electron lifetime the detector is sensitive in the frequency range from 200 GHz to 5 THz. Detector is mounted together with 15 mm diameter hemispherical lens from high-resistivity silicon in an opto-mechanical holder with in-plane micro positioning capability and SMA connector.