Del Mar Photonics
Trestles Pacifica THz Time Domain Spectrometer is a modular tabletop system for scientific and industrial applications of pulsed THz radiation.
In the electromagnetic spectrum, the frequency range between microwaves and the infrared is often called the THz gap, because it has been rarely used in technology, because of a lack suitable sources and detectors.
First generation of Pacifica THz spectrometers
was based on generation of THz waves in ZnTe crystals irradiated by femtosecond
(ultrafast) laser pulses.
THz pulses are generated with a photoconductive antenna (PCA) hit by ultrafast laser pulses. The detection follows the same principle in a detector PCA.
Antenna materials and structures are available for most common wavelengths (800nm, 1060nm, etc.) so the system may be operated with a broad range of femtosecond lasers. Since all components are mounted on an easy-to-transport breadboard maximum flexibility is assured.
Included is a high voltage square wave generator for powering the emitter antenna. So optical chopping can be avoided and signal-to-noise-ratio and output power will be improved. For spectroscopy applications we offer an optional cover of the setup to purge the measurement system with inert gas.
The system is delivered with a ready-to-use Labview Software including VIs for determining absorption spectra.
Sample spectra for two PCA2 40-05-10 (emitter and equal detector) excited with 220fs Pulses with 100mW @ 1064nm each.
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• Spectral Range: 0.1 - 3 THz (depending on laser pulse width and choice of antenna)
• Spectral Resolution: approx. 1 GHz (depending on scan range)
• Size: 600 mm x 450 mm Breadboard (except laser & electronics)
• Including Labview Software for multiple applications such as absorption spectroscopy
• Optional cover for use with nitrogen inert gas
Scope of delivery:
• 600mm x 450mm breadboard with all IR-optics and optomechanics on top
• Delay stage (150 mm travel distance)
• THz emitter & detector: Photoconductive antenna
• THz optics:2 gold coated off-axis parabolic mirrors
• Voltage supply for emitter PCA
• Labview software
• Cover for inert gas (optional)
• Lock-In suitable to use with detector and software (optional)
• Femtosecond pulse laser Trestles Opus
• PC or Laptop computer with labview licence version 8.0 or higher
Trestles Opus brochure
Unique properties of THz waves make them interesting for variety
Due to the low photon energy, the risk of harm through ionization seems negligible.
Many materials like paper, plastics and fabrics are transparent to THz radiation, while water absorbs and metals reflect the radiation. Due to its long wavelengths, the radiation is insensitve to surface roghness. Many organic substances have characteristic spectroscopic signatures in the THz range.
Measurement of moisture content in paper during its fabrication
Detection of concealed weapons
Related Teraherts Products from Del Mar Photonics
New THz band pass and long pass optical filters based on porous silicon and metal mesh technologies
Generation of 10 µJ ultrashort terahertz pulses by optical rectification using Wedge TiSapphire Multipass Amplifier
Crystals for THz generation:
Gallium Phosphor GaP 110-cut crystals for THz applications
GaSe is used as infrared nonlinear crystal and for THz applications GaSe crystal, Z-cut, 10x10x1 mm
ZnTe crystals for THz generation ZnTe crystal, 10x10x0.5 mm, 110-cut
Photoconductive Antenna for terahertz waves
iPCA - interdigital Photoconductive Antenna for terahertz waves
THz detectors: Golay cell and LiTaO3 piroelectric detectors
Band pass filters with center wavelengths from 30 THz into GHz range
Long pass filters with standard rejection edge wavelengths from 60 THz into GHz range