IR Filters
Infrared Optical Filters
Infrared optical filters represent a class of precision spectral control components designed to manage infrared radiation within imaging, sensing, and laser-based systems. Rather than serving as passive accessories, these filters play an active role in defining usable signal bands while suppressing unwanted background radiation across near-, mid-, and long-wave infrared regions.
At Star-optics, we manufacture high-performance infrared (IR) optical filters for applications including thermal imaging, industrial sensing, medical diagnostics, semiconductor processing equipment, and defense-related optical platforms. Our filters are engineered to deliver stable spectral performance while maintaining mechanical robustness suitable for real-world operating environments.
Comprehending Infrared Optical Filters
Infrared filters are specifically designed to selectively transmit defined portions of the infrared spectrum while blocking visible light, thermal background radiation, or out-of-band infrared energy. In practical system design, their primary function is to improve signal-to-noise ratio, protect sensitive detectors, and reduce unwanted thermal load within optical assemblies.
Depending on system requirements, IR filters may function as longpass, bandpass, cut-off, or blocking elements. Each configuration is defined by its spectral transmission window and rejection regions, which are carefully controlled during coating design and fabrication.
Spectral Performance and Key Technical Specifications
Star-optics IR filters are designed with tight spectral control to ensure predictable performance in real operating conditions. Depending on wavelength range and application, filters can be optimized for high peak transmission within the passband while maintaining deep blocking outside the specified spectral region.
Typical technical capabilities include:
| Parameter | Typical Capability |
|---|---|
| Spectral Range | NIR / SWIR / MWIR / LWIR |
| Peak Transmission | >90% (within specified passband) |
| Blocking | OD4 – OD6+ (outside passband) |
| Center Wavelength Tolerance | ±1–5 nm (application dependent) |
| Angle of Incidence | 0° (standard), AOI-optimized designs available |
| Surface Quality | 60-40 or better |
| Clear Aperture | >80% |
| Operating Temperature | -45 °C to +85 °C (higher available) |
| Environmental Durability | MIL-STD-810F, MIL-C-48497A compliant |
Features
Dielectric thin-film coatings for high durability and environmental stability
Excellent temperature stability with minimal spectral shift
Low surface scatter for improved imaging performance
Optional hard coatings for harsh environments
Center wavelength tuning available via angle-of-incidence control
Typical IR Filter Spectral Options
| IR Filter Type | Passband (nm) | Blocking Range (nm) | Blocking Level | Typical Thickness (mm) |
|---|---|---|---|---|
| IR Longpass | 800 – 2500 | 350 – 780 | OD4 – OD6 | 0.5 – 2.0 |
| IR Bandpass | 940 ± 10 | 350 – 900 & 980 – 2500 | OD4 – OD6 | 0.5 – 1.5 |
| IR Bandpass | 1064 ± 10 | 350 – 1000 & 1120 – 2500 | OD5+ | 0.5 – 2.0 |
| IR Bandpass | 1550 ± 20 | 350 – 1450 & 1600 – 2500 | OD5+ | 0.7 – 2.0 |
| IR Blocking | 400 – 650 | 700 – 2500 | OD4 – OD6 | 0.7 – 2.0 |
| IR Cut (Standard) | 400 – 650 | 700 – 1100 | OD4 | 0.5 – 1.1 |
| IR Cut (Wide-Range) | 400 – 650 | 700 – 1700 / 2500 | OD5 – OD6 | ≤ 1.0 |
Custom Infrared Optical Filters
In addition to standard configurations, Star-optics offers custom infrared optical filter solutions developed to meet specific spectral, mechanical, and environmental requirements. Our engineering team works closely with customers to define wavelength ranges, blocking levels, substrate materials, coating architectures, and operating conditions based on actual system constraints.
Whether for prototype evaluation or volume production, we support custom IR filter development with a focus on repeatability, reliability, and real-world performance. Please contact Star-optics for detailed product information or to discuss infrared filter solutions tailored to your application.
