An optical component substrate is the foundational carrier and platform for manufacturing all optical elements. It is a blank of optical material that has undergone preliminary forming and polishing, and its surface has not yet been coated with functional optical thin films. Its core function is to provide a near-perfect physical carrier for subsequent precision processing and coating.
Material Selection and High-Purity Assurance
Precision Machining and Superior Surface Figure
Comprehensive Testing and Traceability
| Material | Primary Transmission Band (Transmittance >80%) | Short-Wavelength Cut-off (Approx.) | Long-Wavelength Cut-off (Approx.) | Curve Characteristics & Key Absorption Peaks |
| Fused Silica | 0.18 µm - 2.5 µm | ~0.17 µm (Deep UV) | ~3.5 µm (IR) | Exceptionally flat and broad. Significant OH⁻ absorption peak at 2.7 µm. High-purity "UV-grade" maintains high transmittance below 0.2 µm. |
| Calcium Fluoride | 0.13 µm - 9 µm | ~0.13 µm (VUV) | ~10 µm | One of the widest transmission windows. Weak absorption bands around ~3 µm and ~6-7 µm. Hygroscopic – requires protection. |
| Sapphire | 0.15 µm - 5.5 µm | ~0.15 µm (Deep UV) | ~6 µm | Very hard and durable. Smooth curve overall with weak absorption near ~3 µm and ~4.3 µm. |
| Silicon | 1.2 µm - 7 µm | ~1.1 µm (Bandgap edge) | ~15 µm (Multiple absorptions) | Opaque in visible light. Transmittance rises sharply from 0% at ~1.1 µm to >50%. Declines beyond 6-7 µm due to lattice absorption. |
| Zinc Selenide | 0.6 µm - 16 µm | ~0.55 µm (Visible) | ~18 µm | Famous broad-band "yellow window". Appears yellowish in visible light. Very high (>70%), smooth transmittance from 2-14 µm. |
| Zinc Sulfide | 0.4 µm - 12 µm | ~0.35 µm (Near-UV) | ~14 µm | Standard grade appears light yellow in visible light. Excellent in the 8-12 µm thermal imaging band. Multispectral grade is clearer in visible. |
| BK7 Glass | 0.35 µm - 2.2 µm | ~0.3 µm (Near-UV) | ~2.7 µm | Standard visible material. Flat and highest (~92%) in the visible range (400-700nm). Declines in UV and NIR due to absorption. |
