THz Emitters & Detectors

THz Emitters & Detectors
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  • Based on LT-GaAs or GaBiAs photoconductive material
  • Optimized for wavelengths around 800 nm or 1060 nm
  • Wide spectral range and low noise
  • Sub-picosecond temporal resolution
  • Based on LT-GaAs or GaBiAs photoconductive material
  • Optimized for wavelengths around 800 nm or 1060 nm
  • Wide spectral range and low noise
  • Sub-picosecond temporal resolution

Features & Applications

Features

  • Based on LT-GaAs or GaBiAs photoconductive material
  • Optimized for wavelengths around 800 nm or 1060 nm
  • Wide spectral range and low noise
  • Sub-picosecond temporal resolution
  • Technical passport and test report included

Applications

  • Time-resolved broadband THz spectroscopy
  • Optical pump – THz probe spectroscopy
  • THz imaging

Description

THz emitter and THz detector consists of a microstrip photoconductive antenna (PCA) fabricated on GaAs substrate. Depending on pump laser wavelength either low temperature grown GaAs (LT-GaAs) or GaBiAs is used as photoconductor. On its surface a coplanar Hertzian type dipole antenna structure is formed using AuGeNi metallization. Photoconductive antenna geometry, as well as the properties of photoconductor epitaxial layers are optimized for highest THz radiation output efficiency, while preserving optimal bandwidth. As a result, typical emitted THz radiation power exceeds 10 μW, when pumped by laser with 30 mW output power and 150 fs pulse duration. FWHM bandwidth of detection system exceeds 700 GHz with usable spectral range of 0.1–4 THz.

THz emitter or detector is illuminated by laser beam from panel side. Laser beams must be focused between two electrodes (Fig. 1).

The gap between metallic contacts is similar to laser spot diameter in detector case and larger – in emitter case. THz radiation is collected by integrated lens, manufactured from high-density silicon, mounted on X-Y stage. EKSPLA offers two standard types of these lenses: for collimated or diverging THz beam output. In second case PCA is placed in aplanatic point of silicon lens, which reduces THz beam aberrations. Adjustment screws are used for Si lens positioning onto PCA center. SMA sockets on back side of the housing are used for connecting DC or AC bias to THz emitter and lock-in amplifier input to THz detector. Any of three M6 holes can be used for THz emitter mounting on optical table.

Specifications

 EmittersDetectors
ModelEMT-08EMT-10DET-08DET-10
Photoconductive antenna
Photoconductive materialLT-GaAsGaBiAsLT-GaAsGaBiAs
Dimensions of the wafer5 x 1.5 mm
Thickness600 µm
Antenna typestrip linedipole
Bias voltage50 V max, 40 V typical-
Central THz frequency~ 0.5 THz-
Detected THz bandwidth-> 4 THz
Integrated focusing lens
MaterialHRFZ-silicon
Geometrical formhyper-hemi-sphere
THz beam outputcollimated or diverging-
X-Y adjustable stage range± 3 mm
Pump beam parameters
Excitation wavelength800±40 nm1060±40 nm800±40 nm1060±40 nm
Average power 1)< 50mW< 30mW< 50mW< 30mW
Pulse duration< 150 fs
Pulse repetition rate20-100 MHz
Beam profilenear to Gaussian
Beam diameter 2)~ 2 mm
  1. Subject to laser pulse duration, repetition rate and beam size at the surface of wafer
  2. Recommended value, if used with EKSPLA THz emitter/detector mount of THz spectroscopy kit

Drawings & Performance

Ordering information

DescriptionModelNotes
THz emitter for 800 nm wavelengthEMT-8Includes Si lens and coaxial cable with BNC connector
THz detector for 800 nm wavelengthDET-8Includes Si lens and coaxial cable with BNC connector
THz emitter for 1060 nm wavelengthEMT-10Includes Si lens and coaxial cable with BNC connector
THz detector for 1060 nm wavelengthDET-10Includes Si lens and coaxial cable with BNC connector

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