Dielectric high-reflection coatings delivering >99.5% reflectance for laser resonators, interferometers and precision optical systems. Superior to metallic mirrors in reflectance and laser damage threshold.
High-reflection coatings designed to reflect a specific wavelength band with minimal loss. Used in laser cavities, beam steering and optical resonators. Damage threshold depends on coating design and substrate.
High-reflection dielectric coatings use alternating quarter-wave stacks of high and low refractive index materials to create constructive interference for reflected light. Each interface contributes a small reflection that adds coherently.
A typical HR design uses 20-40 alternating layers of Ta2O5 (n≈2.1) and SiO2 (n≈1.46). The reflectance bandwidth increases with the index contrast ratio. More layer pairs yield higher peak reflectance.
Unlike metallic mirrors that absorb 2-15% of incident light, dielectric HR mirrors can achieve total reflectance exceeding 99.99% with minimal absorption (< 10 ppm). This makes them essential for high-finesse optical cavities and high-power laser systems.
The reflectance bandwidth of a standard HR coating is typically 5-15% of center wavelength. Broader bandwidth designs require more layers or specialized designs like chirped mirrors for ultrafast laser applications.
| Parameter | Typical Values | Notes |
|---|---|---|
| Reflectance | > 99.5% (up to 99.999%) | At design wavelength |
| Wavelength Range | 248nm - 10.6μm | Deep UV to far-IR |
| Bandwidth | 5-15% of center λ | Custom designs available |
| Absorption Loss | < 50 ppm typical | IBS deposition |
| LIDT (ns pulses) | Available: 10-60 J/cm² | 1064nm, 10ns, ISO 21254 |
| LIDT (CW) | Available: 5-50 MW/cm² | Depends on absorption |
| Surface Quality | 20/10 to 60/40 scratch-dig | Per MIL-PRF-13830 |
| Flatness | λ/10 to λ/2 | At 632.8nm |
| Deposition | IBS, IAD, e-beam | IBS for highest LIDT |
| Material Pair | Index Contrast | Range | Application |
|---|---|---|---|
| Ta2O5/SiO2 | 2.1/1.46 | 350nm-10μm | General laser HR |
| HfO2/SiO2 | 1.9/1.46 | 250nm-10μm | High-LIDT UV-VIS |
| TiO2/SiO2 | 2.35/1.46 | 400nm-8μm | Visible broadband HR |
| Al2O3/SiO2 | 1.63/1.46 | 200nm-4μm | Deep UV HR (193nm+) |
| ZnS/YbF3 | 2.2/1.5 | 2-12μm | IR HR mirrors |
| Ge/SiO2 | 4.0/1.46 | 2-14μm | Far-IR HR |
HR mirrors form the cavity end mirrors in solid-state, fiber and gas lasers. Requirements: R > 99.8%, high LIDT, low absorption.
High-finesse Fabry-Perot interferometers require R > 99.9% mirrors for narrow linewidth filtering and precision metrology.
Fold mirrors in laser beam delivery systems need HR coatings at the operating wavelength with minimal wavefront distortion.
Cavity-enhanced filters and wavelength-division multiplexing devices use HR coatings as part of thin-film filter stacks.
PhotonEdge offers coated optical components compatible with High-Reflection (HR) Coatings. Explore related products below.
High-performance dielectric mirrors can achieve R > 99.999% using 40+ layer designs with IBS deposition. Such mirrors are used in gravitational wave detectors and cavity QED experiments.
Dielectric HR mirrors offer higher reflectance (>99.5% vs 85-95% for metals), higher LIDT, and lower absorption. However, they are wavelength-specific, while metallic mirrors work across broad spectral ranges.
LIDT varies by material and deposition. Ta2O5/SiO2 by IBS typically achieves 30-60 J/cm² at 1064nm/10ns. HfO2/SiO2 designs for UV can reach 10-20 J/cm² at 355nm.
Yes, but the design must be optimized for the specific AOI. The reflectance band shifts toward shorter wavelengths at oblique angles, and s/p polarization splitting occurs.
Our optical engineers can help you select or design the optimal coating for your application.
Request a QuoteTo help us recommend the right coating for your application, please provide the following information:
Center wavelength and bandwidth range
Design angle and acceptance range
Target transmission, reflectance, or R-value
CW power or pulse energy and repetition rate (if applicable)
Temperature range, humidity, vacuum, or cleanroom requirements
Our engineering team can recommend the optimal coating for your application and specifications.