Terahertz Detector

LT-GaAs 1900,- EUR (Excluding VAT)  
GaAsBi   2500,- EUR (Excluding VAT)   
Integrated preamplifier   +150,- EUR (Excluding VAT)   

Principle of Operation

The free space THz detector consists of a micro strip antenna integrated with photoconductor and silicon lens mounted on the back side of photoconductive antenna.

Low temperature grown GaAs (LT-GaAs) or GaBiAs is used as photoconductor. Semiconductor material depends on laser wavelenght. Total GaAs substrate thickness is about 600 µm. Antenna is formed using AuGeNi metallization.

THz detector is illuminated by laser beam from panel side. Laser beams must be focused into photoconductor antenna gap A (Fig. 1). Si lens is used for THz radiation input. Adjustment screws are used for Si lens positioning in point of view of microstrip antenna center. SMA socket is used for connecting lock-in amplifier input with THz detector. Any of three M6 holes can be used for THz detector mounting on optical table.

Fig 1. Microstrip antenna drawing

Standard Specifications

LTG-GaAs based photoconductive switch:

  • Dimensions of the wafer: 5x1.5 mm typical
  • Pumping wavelegth: 800 ± 40 nm.
  • Pumping power: < 50 mW
  • Integrated focusing lens: Si.
  • X-Y adjustable stage range: ± 3 mm
  • Detected THz bandwidth 5 THz (with 100 fs laser pulse duration)
  • Maximum of the THz spectrum at 400GHz
  • Signal-to-noise ratio > >55 dB

Fig 2. Typical spectra when used with TERAVIL THz emitter.

GaBiAs based photoconductive switch:

  • Dimensions of the wafer: 5x1.5 mm typical
  • Registered THz signal: see Fig. below for THz waveform and FFT spectrum.
  • Pumping wavelegth: 1050 ± 40 nm.
  • Pumping power: < 25 mW
  • Integrated focusing lens: Si.
  • X-Y adjustable stage range: ± 3 mm
  • Detected THz bandwidth 5 THz (with 70 fs laser pulse duration)
  • Maximum of the THz spectrum at 400GHz
  • Signal-to-noise ratio > >55 dB

Fig 3. Typical detected spectra when used with TERAVIL THz emitter.