Del Mar Photonics

Terahertz Imaging

Active terahertz imaging with high acquisition rates and its application for moisture sensing

In this paper authors give a short introduction on THz imaging and exemplarily present possible applications in the paper fabrication and in the security sector. They also describe a method for depth imaging with a frequency-swept continuous-wave electronic THz source.

Diagnosing water content in paper by terahertz radiation

Authors explore the application of terahertz spectroscopic techniques
for the remote determination of the water content of paper. The aim
is the development of a rapid diagnostic imaging tool applicable in paper
fabrication processes. THz radiation offers a high sensitivity for water, a
good spatial resolution, and insensitivity to scattering at the paper surface.
The advent of THz cameras makes fast large-area image detectors feasible.
In this paper, we show for the case of a 0.6-THz fixed-frequency system,
that the water content of paper can be determined with high accuracy. We
demonstrate a quantitative (calibrated) method for determining the moisture
content in paper based on extinction and phase measurements in the lower
THz range with a spatial resolution in the mm-range and scanning times
below two minutes.


Teraherts products from Del Mar Photonics

Pacifica THz Time Domain Spectrometer

Generation of 10 J 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

More References:

Broadband THz Generation from Photoconductive Antenna
Terahertz Waves for Communications and Sensing

Terahertz wave imaging: horizons and hurdles
by X-C Zhang

Terahertz (THz) science will profoundly impact biotechnology. It has
tremendous potential for applications in imaging, medical diagnosis, health
monitoring, environmental control and chemical and biological identification.
THz research will become one of the most promising research areas in the
21st century for transformational advances in imaging, as well as in other
interdisciplinary fields. However, terahertz wave (T-ray) imaging is still in
its infancy. This paper discusses the uniqueness and limitations of T-ray
imaging, identifies the major challenges impeding T-ray imaging and proposes
solutions and opportunities in this field. It also concentrates on the generation,
propagation and detection of T-rays by the use of femtosecond optics.