Hyper-Hemispherical HRFZ-Si THz Lens

  • High Resistivity Float Zone Silicon (HRFZ-Si)
  • Design Wavelength: 300 μm (1 THz)
  • Designed for Use with a THz Antenna with a 600 μm Thick Substrate


Hyper-Hemispherical HRFZ-Si Lens for THz Radiation


HSL12 Si Lens Shown as an Integrated Component of the PCA800 THz Antenna (Not to Scale)

THz Output

HSL12 Hyper-Hemispherical Si Lens


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Material Undoped HRFZ-Si
Specific Resistance >10 kΩ*cm
Index of Refraction at 1 THz 3.41
Clear Aperture >90% of Diameter
Surface Quality  80-50 Scratch-Dig
Radius of Curvature 6.0 mm
Thickness  7.1 mm
Thickness Tolerance ±0.1 mm
Optic Cleaning Tutorial


  • Designed for Use with 600 μm Thick THz Photoconductive Antenna
  • Design Wavelength: 300 μm (1 THz)
  • Index of Refraction at 1 THz: 3.41
  • Index of Refraction Matched to Antenna for Minimal Refraction at Surface

The HSL12 Hyper-Hemispherical High Resistivity Float Zone Silicon (HRFZ-Si) Lens for THz radiation is designed for use in direct contact with a THz photoconductive antenna. The hyper-hemispherical shape, along with an index of refraction close to that of the antenna, allows for a large (~70°) collection angle of the THz radiation. The exact collection angle and THz output profile will depend on the antenna used. The HSL12 lens delivers a divergent THz beam that can be collimated or focused with an additional THz TPX or PTFE lens or an off-axis parabolic mirror.

HRFZ-Si is suitable for a wide range of wavelengths from NIR (1.2 µm) to millimeter (1000 µm) waves. This material has superior transmission properties due to its high resistance and lack of absorption lines in the THz region, making it ideal for applications such as THz time-domain spectroscopy. 

Posted Comments:
user  (posted 2023-06-12 16:44:37.557)
Hello, I was wondering if you guys also sell a lens mount for the Hyper-Hemispherical HRFZ-Si THz Lens? Thanks!
jpolaris  (posted 2023-06-15 02:17:03.0)
Thank you for contacting Thorlabs. The HSL12 hyper-hemispherical HRFZ-Si lens could be mounted in a Ø1/2" lens tube and retained with two retaining rings. The outer diameter of HSL12 is Ø12.0 mm. To center the lens within the Ø1/2" lens tube, a retaining ring would first need to be threaded into the tube. Then, the HSL12 could be centered onto that retaining ring. A second retaining ring would then be used to secure the lens in place. We offer extra-thick retaining rings to provide clearance for spanner wrenches when using especially thick optics. For example, SM05RRC. If you already have a 16 mm cage system in your lab, you might consider our SP14 cage plate, which is designed for Ø12.0 mm optics. I have reached out to you directly to discuss mounting options.
SeongHun Jeon  (posted 2022-08-09 14:54:44.52)
Hello, this is Korea Maritime University's Optoelectronic Lab. I want a Hyperhemispheric silicon lens with a diameter of 10mm and a height of 6.445mm. Can you customize it? I'd appreciate it if you could reply.
cdolbashian  (posted 2022-08-15 04:36:38.0)
Thank you for reaching out to us with this inquiry. At this time we are not able to produce a custom Hyperhemispherical lens. For future custom inquiries, please reach out to techsales@thorlabs.com.

Hyper-Hemispheric HRFZ-Si THz Lens

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+1 Qty Docs Part Number - Universal Price Available
HSL12 Support Documentation
HSL12Hyper-Hemispherical HRFZ-Si Lens for THz Radiation, Ø12 mm