High Resistivity Float Zone Silicon Optics for THz Applications
With the exception of synthetic diamond, high resistivity silicon is practically the single isotropic crystalline material suitable for the extremely wide range from NIR (1.2 µm) to MM (1000 µm) waves and more. However in comparison with diamond it is considerably cheaper to grow and machine. Moreover it may have considerably bigger dimensions what allows to vary the range of produced parts. Also it is obvious that silicon is one of most technological materials allowing manufacturing the elements of fast-developing THz electronics based on that. For THz applications we offer High Resistivity Float Zone Silicon (HRFZ-Si) maintaining 50-54% transmission to 1000 µm (and for longer wavelengths up to 3000 and even to 8000 microns upon custom request).
Fig. 1 HRFZ-Si transmission in FIR-THz range (sample thickness - 5 mm). Measurements were made on Bruker IFS-120V spectrometer.
Our HRFZ-Si products were approved in tens of laboratories and many companies over the world and are successfully used in THz experiments and devices.
Lenses
Material |
HRFZ-Si |
Shapes |
Spherical, Hyper-Hemispherical, Hemispherical, Hypo-Hemispherical, and Bullet |
Available diameters, mm |
2–100 |
Diameter tolerance, mm |
+/-0.1 |
Thickness tolerance |
2% of thickness but not more than 0.1 mm |
Surface quality, scr/dig |
80/50 |
Surface accuracy, mm |
+/-0.01 deviation from ideal sphere and plane |
Tydex always has stock of polished “ball-shaped” blanks of HRFZ-Si with standard diameters (2.0, 4.0, 6.0, 8.0, 10.0, 12.0 mm). Upon your request we can polish flat surface to make lens with specified thickness and supply required hyper-/hypo-/hemi-spheres within two weeks. Besides this Tydex has finished parts of different dimensions and shapes in stock which we can offer upon your request and supply within a week. Please ask us for the current stock.
Also for focusing THz radiation we offer HRFZ-Si meniscus lenses with the following parameters:
Material |
HRFZ-Si |
Effective focal length (EFL) tolerance, % |
+/-1 |
Available diameters, mm |
to 100 |
Diameter tolerance, mm |
+0.0 / -0.1 |
Thickness tolerance, mm |
+/-0.1 |
Edge thickness variation, mm |
<= 0.05 |
Clear aperture, % of diameter |
90 |
Surface quality, scr/dig |
80/50 |
Surface figure (power-irregularity) @ 633 nm |
varies depending on radius |
Our standard, available from stock, positions are listed below:
No. | Diameter | EFL * | |
inches | mm | mm | |
1 |
1.0 |
25.4 |
25.0 |
2 |
1.0 |
25.4 |
50.0 |
3 |
1.0 |
25.4 |
100.0 |
4 |
1.0 |
25.4 |
200.0 |
5 |
2.0 |
50.8 |
25.0 |
6 |
2.0 |
50.8 |
50.0 |
7 |
2.0 |
50.8 |
75.0 |
8 |
2.0 |
50.8 |
100.0 |
9 |
2.0 |
50.8 |
150.0 |
10 |
2.0 |
50.8 |
200.0 |
*All EFLs are calculated for wavelength 300 µm. EFL deviations related with refraction index dispersion at the edges of THz range (30-3000 µm) are negligible in comparison with EFL tolerances manufactured (+/-1%).
Manufacturing of custom-made lenses is also acceptable.
Besides listed optics for handling of THz radiation Tydex offers such parts as beam-splitters, windows, wafers, and prisms for different THz applications. You can find our standard specification for such parts below. Also in stock we always have the parts of standard sizes as windows and wafers with diameters 1” , 2” , 3” , 4” of different thickness.
Material |
HRFZ-Si |
Available sizes, mm |
to 100 |
Diameter or cross-cut tolerance, mm |
+0.0 / -0.1 |
Thickness tolerance, mm |
+/-0.1 |
Best angle tolerance, arc.min |
1 |
Surface quality, scr/dig |
60/40 |
Surface accuracy, mm |
+/-0.01 deviation from ideal plane |
Please pay attention that we do not supply HRFZ-Si in blanks or as raw material. Our standard products are finished (polished) parts.