Infrared Filters

Infrared Filter Solutions For
SWIR, MWIR, and LWIR Applications

Infrared optical filters for long-pass or bandpass use, photographed on a neutral background.

Andover IR Filters

Precision IR Filtering from 2µm to 14µm

Infrared filters are critical components in thermal imaging, spectroscopy, sensing, aerospace, and defense systems. Designed to selectively transmit infrared wavelengths while blocking unwanted radiation, these filters help improve signal clarity, spectral accuracy, and overall optical performance.

Andover Corporation manufactures infrared optical filters using advanced thin-film coating technologies and premium IR-transmitting materials to support demanding applications across the SWIR, MWIR, and LWIR spectral regions.

Our IR filter solutions provide:

  • Precise wavelength control from near-IR through LWIR
  • High transmission with strong out-of-band blocking
  • Custom spectral designs for specialized applications
  • Durable coatings for demanding operating environments

Whether you need IR bandpass filters, long wave pass filters, neutral density filters, or coated IR substrates, Andover Corporation supports both prototype and production-scale optical programs.

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IR Filter Construction Technologies

Infrared filter performance depends heavily on coating technology, substrate selection, and environmental durability requirements. Andover Corporation supports multiple IR coating approaches to optimize transmission performance, wavelength range, environmental stability, and manufacturability.

Magnetron Sputtering

Advanced hard-coated thin-film technology offering:

  • Exceptional environmental durability
  • Stable spectral performance across production batches
  • Dense low-moisture coatings for long-term reliability
  • Excellent performance from NIR through MWIR applications

Resistance Evaporation

Flexible infrared coating approach supporting:

  • Custom prototype through production volumes
  • Broad infrared wavelength coverage
  • Scalable optical coating designs
  • Large-format IR optical components and substrates
  • Secure supply chain production

Diamond-Like Carbon (DLC) Coatings

Enhanced durability and environmental protection for demanding IR optical systems on high-index materials.

  • Exceptional durability for Germanium (Ge) and Silicon (Si) optics
  • Low reflectance with a refractive index ~2.0
  • Outstanding resistance to humidity, salt fog, and abrasion
  • Enhanced protection for outer-facing infrared lenses

IR Featured Products

From single-layer simplicity to advanced multi-layer performance

IR filters leverage sophisticated thin-film designs and specialized materials to achieve precise control over infrared radiation. Understanding the available construction methods helps ensure optimal filter selection for your application:

Infrared optical filters for long-pass or bandpass use, photographed on a neutral background.

IR Bandpass Filters

Precision spectral isolation filters designed to transmit specific IR wavelength bands while providing deep blocking of out-of-band radiation. Available in both narrow and broadband configurations for optimal spectral selection.
  • Wavelength Range2.0μm - 14.0μm
  • Bandwidth Options1% to 50% of center wavelength
  • Transmission>80% typical
  • BlockingOD3 average
High Transmission
Deep Blocking
Custom Options
Infrared optical filters for long-pass or bandpass use, photographed on a neutral background.

Standard IR Long Wave Pass

Sharp cut-on filters for isolating longer IR wavelengths while providing deep rejection of shorter wavelengths. Ideal for order-sorting and blocking applications.
  • Cut-on Range1.0μm - 8.0μm
  • Transmission>85% above cut-on
  • RejectionOD3 below cut-on
Sharp Transition
Deep Blocking
Standard Sizes
Optical filter or component from Andover Corporation shown on a white background.

IR Neutral Density Filters

Precision attenuation filters for the infrared region, utilizing metallic coatings on germanium substrates. Provides controlled reduction of IR intensity while maintaining spectral neutrality.
  • Wavelength Range2.0μm - 14.0μm
  • Optical Density Range0.3 to 3.0
  • SubstrateGermanium
Spectrally Neutral
Durable Coating
AR Coating Optional
IR Neutral Density Filters

IR Neutral Density Filter Sets

Calibrated sets of IR neutral density filters in protective storage cases. Ideal for systematic IR intensity control and calibration applications.
  • Set Contents6 or 9 filters
  • ND Range0.3 to 3.0
  • CalibrationIndividual data included
Matched Sets
Storage Case
Calibrated
Infared Supressing-600w

IR Suppressing Filters

Enhanced IR blocking filters that combine dielectric reflection and absorption for extended infrared suppression. Ideal for low-power applications requiring maximum heat reduction.
  • Visible Transmission ≥65% (400nm-600nm)
  • IR Blocking ≤10% avg (700nm-2000nm)
  • Operating Temperature Up to +100°C
  • Construction Dielectric + Absorbing Glass
  • Substrate Borosilicate glass
Extended IR Blocking
Absorption Enhanced
Low Power Use
Cost Effective
Infrared Windows and Substrates

IR Windows and Substrates

High-quality IR-transmitting materials for windows, substrates, and custom optics. Available in various materials to match your wavelength and environmental requirements.
  • MaterialsGe, Si, ZnSe, CaF2, Sapphire
  • Surface Quality60-40 scratch-dig
  • Flatnessλ/4 per inch
Multiple Materials
Precision Polished
Custom Sizes

Frequently Asked Questions

What is an infrared (IR) filter?

An IR filter is an optical filter designed to transmit specific infrared wavelengths while blocking others. These filters are commonly used in thermal imaging, spectroscopy, and aerospace systems.

What types of IR filters does Andover Corporation offer?

We manufacture IR bandpass filters, long wave pass filters, IR neutral density filters, and IR suppressing filters. Each type supports different wavelength ranges and applications from 2µm to 14µm.

Which materials are used for Andover’s infrared filters?

Our IR filters are fabricated using materials such as Germanium, Silicon, Zinc Selenide, and Sapphire, selected for their infrared transmission and durability.

Can I request a custom infrared filter?

Yes. We offer custom IR filter design based on your exact wavelength, bandwidth, and substrate requirements—ideal for defense, medical, or research applications.

What are typical applications for IR filters?

IR filters are used in thermal cameras, gas sensors, FLIR systems, aerospace instruments, and spectrometers, among other applications -- anything where precise IR control is critical!

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Infrared Optics and Applications

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