Silicon Optical Windows
Single-crystal silicon windows for mid-wave infrared (MWIR) systems operating from 1.2um to 7um. Lightweight alternative to germanium with excellent thermal conductivity. Ideal for 3-5um thermal imaging and laser systems.
Key Specifications
Material Options
Select the optimal optical material based on your wavelength, power, thermal environment and mechanical requirements.
- Silicon (Si) — Lightweight MWIR material. Best for 3-5um band. Excellent thermal conductivity for high-power applications.
- Germanium (Ge) — Higher refractive index for more compact designs. Covers both MWIR (3-5um) and LWIR (8-14um). Heavier than Si.
- ZnSe (Alternative) — Broadband IR from 0.6um to 18um. Better when you need visible alignment beam transmission. Softer and hygroscopic at high temperature.
Coating Options
Coatings are engineered around your specific wavelength and operating conditions.
- AR @ 3-5um (MWIR) — R < 0.5% per surface. Standard for MWIR thermal imaging and gas sensing.
- AR @ 1-3um (SWIR) — R < 0.5% per surface. For short-wave IR laser and imaging systems.
- BB AR MWIR — R < 1% across 3-5um. For broadband MWIR applications.
- DLC Overcoat — Hard protective layer for harsh environment deployments. Extends coating lifetime.
Manufacturing Tolerances
We optimize specifications to match your system requirements — not over-specify. Tighter tolerances increase cost without always improving system performance. Typical manufacturing capabilities:
- Surface quality: from 60-40 to 10-5 scratch-dig
- Surface flatness: from λ/4 to λ/20 per inch
- Dimensional tolerance: ±0.01mm to ±0.05mm
- Centration: <3 arc min standard, <30 arc sec precision
Inspection & Quality
Every component undergoes 100% inspection before shipment with full documentation including interferometer reports, spectral curves, surface quality images and dimensional data.
- Laser interferometry: λ/100 resolution
- Spectrophotometry: 190nm – 25μm
- Surface inspection: MIL-PRF-13830B compliant
- Dimensional metrology: ±0.01mm accuracy
Applications
- MWIR (3-5um) thermal imaging and FLIR systems
- IR gas sensing and spectroscopy windows
- Laser system protective windows at 1-5um wavelengths
- Vacuum chamber viewports for IR observation
- High-power laser output windows (excellent thermal conductivity)
- Aerospace IR sensor windows (weight-optimized)
- Industrial process monitoring at MWIR wavelengths
Engineering Considerations
Si vs Ge for MWIR: Silicon is preferred over germanium for MWIR (3-5um) systems when weight is a concern. Si has less than half the density of Ge (2.33 vs 5.32 g/cm3) and superior thermal conductivity (163 vs 100 W/m-K). However, Ge covers both MWIR and LWIR bands while Si is opaque beyond 7um.
AR coating is essential: With n=3.42, uncoated silicon reflects ~30% per surface. AR coating improves throughput from ~41% to >99% per element. Always specify AR coating for your operating wavelength.
Thermal advantage: Silicon's high thermal conductivity makes it ideal for high-power laser windows and applications with significant thermal loading. The material dissipates heat efficiently, reducing thermal lensing effects.
Frequently Asked Questions
Related Products
Related Technical Resources
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