Quartz Crystal (SiO₂) is a naturally occurring mineral, although most modern applications utilize synthetic quartz grown in controlled conditions to produce high-purity, large-sized crystals. Quartz is a positive birefringent material with applications in wave retardation (e.g., quarter-wave plates) and polarizers. Unlike fused quartz, crystalline quartz offers distinct properties such as birefringence and a structured molecular arrangement.
Due to its high mechanical strength and thermal resistance, Quartz Crystal is ideal for applications involving elevated temperatures, although it should not be processed above 490°C to avoid structural degradation. The material’s optical transmission properties make it a versatile choice for UV and IR optical systems, including scientific, industrial, and defense technologies.
Quartz Crystals are extensively used in both optical and mechanical applications due to their birefringence, optical transparency, and thermal resistance:
| Property | Value |
|---|---|
| Density | 2.649 g/cm³ |
| Melting Point | 1710°C |
| Thermal Conductivity | 10.7 W·m⁻¹·K⁻¹ (parallel) |
| 6.2 W·m⁻¹·K⁻¹ (perpendicular) | |
| Thermal Expansion | 7.1 × 10⁻⁶ K⁻¹ (parallel) |
| 13.2 × 10⁻⁶ K⁻¹ (perpendicular) | |
| Hardness (Knoop) | 741 with 500g indenter |
| Specific Heat Capacity | 710 J·Kg⁻¹·K⁻¹ |
| Dielectric Constant | 4.34 (parallel) |
| 4.27 (perpendicular) | |
| Elastic Coefficients | C11=87 GPa, C12=7 GPa |
| C44=58 GPa, C33=106 GPa | |
| Molecular Weight | 60.06 |
| Structure | Trigonal (hexagonal), P3(2)21 |
| Birefringence (dn/dT) | -5.5 × 10⁻⁶ (parallel) |
| -6.5 × 10⁻⁶ K⁻¹ (perpendicular) |
| Optical Property | Value |
|---|---|
| Transmission Range | 0.18 to 3.5 µm; 40 to 100 µm |
| Refractive Index (No) | 1.54421 at 0.6 µm |
| Refractive Index (Ne) | 1.55333 at 0.6 µm |
| Reflection Loss (2 surfaces) | 8.8% at 0.6 µm |
| Absorption Coefficient | Negligible |
| Reststrahlen Peak | Not applicable |
| Thermo-optic Coefficients | dn/dµ = 0 at 1.3 µm |
| dn/dT = -5.5 × 10⁻⁶ K⁻¹ (para) | |
| dn/dT = -6.5 × 10⁻⁶ K⁻¹ (perp) |
| Specification | Value |
|---|---|
| Flatness | λ/4 at 632.8 nm |
| Surface Quality | 40-20 scratch-dig |
| Parallelism | <1 arc minute |
| Clear Aperture | >90% |
| Chamfer | <0.25 × 45° |
| Dimensional Tolerance | ±0.1 mm |
Quartz Crystals exhibit high transmission rates from UV to IR spectra. For example:
Detailed transmission data can be illustrated in a graph showing %T over a range of wavelengths from 0.18 to 3.5 µm.
Quartz Crystals can be coated for enhanced transmission and reduced reflection in various spectral ranges:
| Product | Specifications | Price (USD) |
|---|---|---|
| Quartz Window | 20 mm × 2 mm, AR-coated | $250 |
| Quartz Plate | 50 mm × 5 mm, uncoated | $450 |
| Quartz Prism | Custom shape, coated | $650 |
| Custom Specifications | Tailored designs | Contact for pricing |
