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Si Optics

Si (Silicon) is one of the hardest optical materials, Silicon optical components are widely used in a variety of infrared applications operating at 1.2 – 7μm wavelength range, including NIR imaging or IR spectroscopy. Optical quality Silicon is generally lightly doped (5 – 40 ohm/cm) to prevent absorption bands and for best transmission above 10 microns. Silicon’s resistivity of 5- 40 Ohm-cm which is higher than most semiconductor applications. Silicon’s low density (2.329 g/cm3) is ideal for use in weight-sensitive applications. Silicon features a Knoop hardness of 1150, making Silicon optical components harder, less brittle alternatives to comparable Germanium optical components.
Silicon is used for windows and lenses mostly in the 2-6µm range, the ideal choice for IR LED lenses. The refractive index is near 3.4 throughout the range. Silicon high thermal conductivity and low weight are attractive features in IR or FTIR applications. Silicon is also used as a high reflectivity mirror substrate for lasers and for IR silicon viewports. Honour Optics is the professional custom infrared spherical/aspherical/cylindrical Silicon lenses manufacturer, welcome to consult wholesale large size infrared Silicon optics and wholesale Infrared and Broadband Silicon lenses.

Si (Silicon) is ideal optical material for use in the 3 to 5µm (MWIR) waveband and as a substrate for optical filters and mirrors. Its transmission is about 50% within the 1 to 6µm, which means anti-reflection coatings are normally required to improve the transmission. Silicon has a high thermal conductivity and low density that makes Si (Silicon) frequently be used for laser mirrors. Monocrystalline Silicon is also useful as a transmitter in the 20-micron range. Silicon has a further passband 30 to 100 microns which are effective only in very high resistivity material.

Customizable infrared Silicon lenses are grown by Czochralski pulling techniques (CZ) and contain some oxygen which causes an absorption band at 5.8 microns, 9.1 microns, and 19.4 microns. To avoid this, Si monocrystalline material can be prepared by a Float-Zone (FZ) process. Optical silicon is generally lightly doped (5 to 40 Ohm*cm) for best transmission above 10 microns.

Silicon is one of the lowest densities of the common IR materials, it is ideal for systems with weight constraints.
It is harder than Ge and not as brittle.
It is the lowest material cost option of all the IR materials.
Si is diamond turnable.

Products manufactured: Lenses, Aspheric Lenses, Binary(Diffractive) Lenses, Windows, Optical Beamsplitters, Optical Filters, Wedges.

Surface finish: Typical specifications for surface quality in the infrared are a 40-20 scratch-dig in the 1.2 to the 3μm spectral region and 60-40 scratch-dig for the 3-7μm area. Diamond Turned surface finishes of 120Angstroms rms or better are typical.

Surface figure the infrared, typical required surface figure ranges from 1/2 wave to 2 waves @0.6328μm and is usually specified depending on the system performance requirements.

AR coating options: In the infrared, typically required surface figure ranges from 1/2 wave to 2 waves @0.6328μm and are usually specified depending on the system performance requirements. welcome to consult procurement customizable infrared Silicon lenses latest price.

Tab. 1. Main Properties of Silicon

Parameter Value
Transmission Range 1.2 to 15 microns
Refractive Index 3.4223 at 5 microns
Reflection Loss 51.0% at 5 µm (2 surfaces)
dn/dT 160 x 10-6/K
dN/dµ = 0 10.4µm
Index of Absorption 1 x 10-3 cm-1 at 3 microns
Density 2.33 g/cm3
Melting Point 1420° C
Thermal Conductivity 163.3 Wm-1K-1 at 273K
Thermal Expansion 4.15 x 10-6/°C
Hardness Knoop 1150
Specific Heat Capacity 703 J/(kg K)
Dielectric Constant 13 at 10GHz
Young's Modulus (E) 131 GPa
Shear Modulus (G) 79.9 GPa
Bulk Modulus (K) 102 GPa
Elastic Coefficients C11=167 MPa, C12=65 MPa,
C44=80 MPa
Poisson Ratio 0.266
Solubility Insoluble in water
Molecular Weight 28.09
Class/Structure Cubic diamond, Fd3m

Tab. 2. Si Refractive index

µm No µm No
1.357 3.4975 1.367 3.4962
1.395 3.4929 1.5295 3.4795
1.660 3.4696 1.709 3.4664
1.813 3.4608 1.970 3.4537
2.153 3.4476 2.325 3.4430
2.714 3.4358 3.000 3.4320
3.303 3.430 3.500 3.4284
4.000 3.4257 4.258 3.4245
4.500 3.4236 5.000 3.4223
5.500 3.4213 6.000 3.4202
6.500 3.4195 7.000 3.4189
7.500 3.4186 8.000 3.4184
8.500 3.4182 10.00 3.4179
10.50 3.4178 11.04 3.4176

Tab. 3. Specification of Silicon options

Specification Typical Level High precision
Sizes 2mm-2300mm 2mm-300mm
Diameter tolerance +/-0.1mm +/-0.05mm
Thickness tolerance +/-0.1mm +/-0.05mm
Surface quality, scr/dig 60/40 20/10
Surface flatness(lambda) L/2 L/10
Parallelism 3 arc min 30 arc sec
Clear Aperture 80% 90%
Chamfer 0.25mm at 45 deg 0.15mm at 45 deg
Coating As requested As requested

Transmission Spectrum

customizable infrared silicon lenses transmission spectrum

Honour Optics offers two kinds of Monocrystalline Silicon: Transmission Grade and Mirror Grade. As the transmission of optical grade material pulling of monocrystalline silicon (OCZ-Si) are widely used in the mid-infrared 1-6um band, infrared transmittance over 50%. Float-zone silicon crystal can be used in a wider band 1-14 um, the area of the high purity fused silicon and even can be used in the infrared waveband (greater than 30 um). Monocrystalline silicon is a good laser reflector material. With its good thermal conductivity, excellent thermal stability, low thermal expansion coefficient, monocrystalline silicon relatively low density, low cost, easy to precision machining, the CO2 laser reflector is the preferred basement materials. Also please be noted that the transmittance does not depend on the crystal orientation. Honour Optics is the professional custom infrared spherical/aspherical/cylindrical Silicon lenses manufacturer, welcome to consult wholesale large size infrared Silicon optics and wholesale Infrared and Broadband Silicon lenses.

Some of standard customizable infrared Silicon lenses optics provided from Honour Optics as summarized as follows, please contact us any time when need:
Silicon windows and wedges uncoated or with an antireflection coating at standard 1.5-6μm, 2-4μm, 3-5μm, 8-12μm.

Silicon optical lenses for collimation or focusing applications that utilize monochromatic light. These lenses are available in a range of sizes or focal lengths for a wide variety of application needs. We also produce HRFZ Si lenses of different types: hyper-hemispherical and bullet for THz applications

IR interference filters, which are integrated into IR applications such as FTIR spectroscopy, are used to transmit or block a specific range of IR wavelengths.

Silicon mirrors are lighter than copper mirrors and lend themselves to lightweight applications with small to medium power output. Silicon mirrors are generally coated with silver, gold and/or dielectric coatings. welcome to consult procurement customizable infrared Silicon lenses latest price.

Honour Optics produces high-quality Si (Silicon) optical components with theoretical transmission and excellent homogeneity. Both monocrystalline and polycrystalline are available. Windows, wedges, filter, lenses, and prisms can be made according to your specifications, with the diameter up to about 300mm.