Other THz Products
THz Lenses & Windows:
Microtech offers a variety of lenses and windows for THz applications including:
• Polished Tsurupica Windows
• Polished Tsurupica Lenses
• Polyethylene Lenses
Download THz Lenses & Windows Datasheet (PDF, 185 KB):
Polished Tsurupica Windows
Apart from high transparency in THz and visible spectral ranges, Tsurupica is also very strong mechanically. Thin Tsurupica windows can be used in cryostats, gas cells or any other systems operating at high pressure.
Ordering Information:
| Model | Diameter / Thickness |
| PTW-1" -3mm | 1" (25.4 mm) / 3 mm |
| PTW-1.5"-4mm | 1.5" (38.1 mm) / 4 mm |
| PTW-2"-4mm | 2" (50 mm) / 4 mm |
Polished Tsurupica Lenses Focus THz and Visible Light
- Tsurupica is highly transparent in THz and visible spectral ranges
(see transmission spectra below). - Refractive index of Tsurupica is the same for THz and visible light (n=1.52).
- It withstands optical polishing.
Ordering Information:
| Model | Lens Type | External Diameter/ Clear Aperture |
Focal Length |
| PTL-1.5"-50mm-AS | Plano-convex, aspheric | 1.5" / 30 mm | 50 mm |
| PTL-1.5"-100mm-AS | Plano-convex, aspheric | 1.5" / 30 mm | 100 mm |
| PTL-2" -50mm-BC | Bi-convex, spherical | 2" / 45 mm | 50 mm |
| PTL-2"-100mm-BC | Bi-convex, spherical | 2" / 45 mm | 100 mm |
| PTL-2"-180mm | Plano-convex, spherical | 2" / 45 mm | 180 mm |
| PTL-1.5"-XXXmm | Plano-convex, spherical | 1.5" / 30 mm | Any > 30 mm |
| PTL-2"-XXXmm | Plano-convex, spherical | 2" / 45 mm | Any > 50 mm |
Polyethylene Lenses
- The lenses are manufactured from a purified high-density polyethylene
- Offer the best performance at frequencies below 1 THz and above 7 THz
- Polyethylene is not transparent in visible and near-IR spectral ranges, so that the lenses
can be used to block light - Polyethylene Lenses are sold mounted in a metal holder, as shown in the photo to the right
| Model | Lens Type | Holder Diameter/ Clear Aperture |
Focal Length |
| PL-60 | Bi-convex, spherical | 2.75" / 2" | 60 mm |
| PL-100 | Bi-convex, spherical | 2.75" / 2" | 100 mm |
Transmission Spectra of Tsurupicaand Polyethylene
The transmission spectra were measured for 2 mm thick slabs which corresponds to an average thickness of a lens (50 mm diameter, 100 mm focal length)
THz Polarizers:
Polarization Rotator
The Polarization Rotator is a wire grid polarizer combined with a mounted mirror placed at an adjustable distance behind the polarizer. It is designed to take an incoming linearly polarized signal and adjust the polarization elliptically.
Download Polarization Rotator Datasheet (PDF, 339 KB):
Free Standing Wire Grid Polarizers
These polarizers are made of 10 µm, 15 µm or 20 µm tungsten wire wound on a circular frame with spacing ranging from 25 µm to 200 µm.
Download Wire Grid Polarizer Drawing, Top & Side View (PDF 28.2 KB):
Ordering Information:
| Polarizer Model | Wire diameter / Wire spacing (mm) | Clear aperture / External diameter (mm) |
| G25 x 10-S | 10 / 25 | 40 / 50 |
| G30 x 10-S | 10 / 30 | 40 / 50 |
| G30 x 10-L | 10 / 30 | 88 / 98 |
| G45 x 10-S | 10 / 45 | 40 / 50 |
| G45 x 10-L | 10 / 45 | 88 / 98 |
| G50 x 20-S | 20 / 50 | 40 / 50 |
| G50 x 20-L | 20 / 50 | 88 / 98 |
| G60 x 15-S | 15 / 60 | 40 / 50 |
| G60 x 15-L | 15 / 60 | 88 / 98 |
| G80 x 15-S | 15 / 80 | 40 / 50 |
| G80 x 15-L | 15 / 80 | 88 / 98 |
| G100 x 20-S | 20 / 100 | 40 / 50 |
| G100 x 20-L | 20 / 100 | 88 / 98 |
| G200 x 20-S | 20 / 200 | 40 / 50 |
| G200 x 20-L | 20 / 200 | 88 / 98 |
New Product! Thin Film Polarizers
Thin Film Terahertz Polarizers are designed for applications in the 0.1-3.0 THz range. The polarizers consist of any array of metal stripes fabricated on a polymer membrane using an ultrafast laser micromachining technique. Typical stripe widthand spacing are about 15um. THz thin film polarizers provide performance comparable to free-standing wire grids, such as G25S and G30S, made of 10um wires spaced by 25um and 30um respectively.
The main advantage of thin film THz polarizers is significantly larger clear aperture - up to 85mm in diameter. For comparison, the G25S and G30S free-standing wire grid polarizers are only available with clear apertures of 40mm
Polarizer Holders
We carry two types of rotating holders for the wire grid polarizers or thin film polarizers.
Model RH1 is designed for 4" diameter polarizers, and enables a 360° rotation.
Model RH2 is designed for 4" diameter polarizers, and enables 2-axis adjustments and 360° rotation.
THz Attenuators:
The attenuator set is ideal for applications where the terahertz signal needs to be attenuated to prevent detector saturation.
Additionally; the broad, flat transmission spectrum shown in figure 1 below makes this set good for both broad spectrum THz and BWO scanning applications. Whether the source is a photoconductive antenna, free electron laser, or backwards wave oscillator this attenuator set with its sputter coated thin film elements is capable of attenuating the signal uniformly.
The set consists of 4 thin film attenuators mounted for easy and rapid deployment. The external diameter of the attenuators are 68mm, and the clear aperture is 60mm. These attenuators may be used as single attenuators or in combination as needed giving additional flexibility and range. The four attenuators are 30%, 10%, 3%, and 1% transmission. The attenuation combinations possible are given in the table below.
Attenuator Set Transmission
Download Attenuator datasheet (PDF, 541 KB)
THz Low Pass Filters:
Our new terahertz (THz) low pass filter is constructed from a micro-structured material that blocks the visible through mid IR while passing THz beams. It is an excellent filter for optical THz generation systems such as time domain THz spectroscopy systems. It has optimal characteristics for use in zinc telluride based systems and for typical photo conductive switch systems as well. As can be seen in the figure below, the measured transmission in the 700 to 850 nm range is below .01%. At wavelengths longer than 975 nm the transmission is below .1%. These measurements were done with a laser beam spectrally filtered to the wavelength of interest from a super-continuum white light coherent source.
THz Low Pass Filter Visible To Mid IR Transmission Spectrum
The transmission of THz waves is above 80% across the .1 to 3 THz range making this an excellent filter even for broadband THz applications. THz measurements were done up to 1 THz with our compact THz spectrometer (TScan-1000) and with additional optical THz generation for the above 1 THz range.
This can be seen in the figure below.
This filter is sold mounted in a 2" diameter holder as shown in the photo above. The clear aperture of the filter is 43 mm
Download THz Filters datasheet (PDF, 441 KB)
Terahertz Low Pass Filter THz Transmission Spectrum
New Product! Band-Pass Filters:
Band-Pass filters allow for the selection of narrow bands in the frequency ranges of 0.1-1.2 THz. These filters utilize multilayer frequency selective surfaces to achieve a desired frequency response. The allowed bandwidth varies with center frequency, from 10 GHz to 200 GHz.
