Choose the Optical Filter Family for Your System
Different optical systems require different transmission windows and blocking behavior. Start with the wavelength region and unwanted spectral energy that must be rejected.
Visible Bandpass Filters
Visible bandpass filters transmit a selected portion of the visible spectrum, approximately 400–700 nm, while rejecting unwanted ultraviolet and near-infrared radiation.
Available configurations can include double-side polished substrates for parallelism and optical flatness, hard-coated single-substrate construction, anti-reflection coatings, and threaded, C-mount, slip-mount or unmounted formats.
Typical uses include machine vision, factory automation, security and surveillance, license-plate recognition, fluorescence imaging, laser analysis and outdoor imaging under strong ambient light.
NIR & Dual Bandpass Filters
Near-infrared bandpass filters transmit a selected range within approximately 700–2500 nm.
Dual bandpass filters transmit two separated spectral regions while blocking wavelengths between and around the two passbands. They are useful where one optical system must support dual-mode or multispectral operation.
Typical applications include day/night surveillance, Intelligent Traffic Solutions, NDVI imaging, precision agriculture, drone platforms, NIR spectroscopy, industrial chemical analysis, machine vision and biomedical fluorescence imaging.
- Strong out-of-band rejection
- Anti-reflection coatings for increased throughput
- Hard-coated single-substrate construction
- 40/20 scratch-dig surface quality
UV Bandpass Filters
UV bandpass filters transmit a selected ultraviolet region, typically within approximately 10–400 nm, while rejecting visible and infrared wavelengths.
Typical uses include PCR and life-science diagnostics, semiconductor inspection, surface inspection, forensic imaging, UV curing, sterilization, fluorescence and DNA analysis.
- Defined UV transmission windows
- High out-of-band blocking
- Anti-reflection coatings for increased UV transmission
- Hard-coated construction
- 40/20 scratch-dig surface quality
- Threaded or unmounted configurations
Shortpass Filters — IR-Cut / Visible-Pass
Shortpass filters transmit wavelengths below a specified cutoff while rejecting longer wavelengths such as NIR and IR.
They are commonly used where visible-light transmission must be maintained while infrared energy is removed from the optical path.
Typical applications include digital cameras, machine-vision color correction, fluorescence excitation, spectroscopy, projection systems and optical thermal management.
- Sharp transition between transmitted and blocked regions
- Durable dielectric coatings
- Configurations optimized around a specified angle of incidence
- Ability to combine with longpass filters to create a custom bandpass window
Longpass Filters
Longpass filters transmit wavelengths above a specified cutoff while reflecting shorter wavelengths.
They can be used independently or combined with shortpass filters where the optical system requires a defined custom transmission window.
Typical applications include camera and sensor windows, fluorescence emission filtering, spectroscopy, laser-light control, thermal management, multispectral imaging and hyperspectral imaging.
- Double-side polished substrates
- 40/20 scratch-dig surface quality
- Anti-reflection coatings
- Oleophobic surface treatment
- Custom cutoff wavelengths
- Threaded, C-mount, slip-mount and custom configurations
Compare Optical Filters by System Requirement
The appropriate filter depends first on which wavelengths must pass and which wavelengths must be rejected.
| Optical Requirement | Filter Direction | Where It Fits |
|---|---|---|
| Isolate selected visible wavelengths while rejecting UV and NIR | Visible Bandpass | Machine vision, surveillance, fluorescence imaging, outdoor imaging |
| Detect NIR or support two separated spectral bands | NIR / Dual Bandpass | Day/night imaging, ITS, NDVI, spectroscopy, multispectral detection |
| Isolate an ultraviolet transmission region | UV Bandpass | Life science, semiconductor inspection, forensic imaging, UV fluorescence |
| Pass visible or shorter wavelengths while rejecting IR | Shortpass / IR-Cut | Cameras, color correction, spectroscopy, projection and thermal control |
| Pass longer wavelengths while rejecting shorter wavelengths | Longpass | Sensor windows, fluorescence emission, spectroscopy, laser and multispectral systems |
Filter selection should then be refined around center wavelength (CWL), full width at half maximum (FWHM), cutoff position, peak transmission, out-of-band optical density, operating temperature, angle of incidence, surface quality, part size and mounting method.
Unsure Which Optical Filter to Choose?
Start with the wavelengths that must pass, the wavelengths that must be blocked and the optical system’s operating conditions.
- Required CWL or cutoff wavelength
- FWHM or passband width
- Transmission target
- Blocking range / optical density
- Angle of incidence
- Substrate preference
- Part size
- Mounting method
From Filter Selection to Finished Optical Components
Optical-filter performance must be considered together with the substrate, mechanical format, surface treatment and final assembly requirements.
- Spectral Requirement Review — Review center wavelength, FWHM, cutoff frequency, peak transmission, blocking optical density, angle of incidence and operating environment before defining the filter configuration.
- Substrate & Surface Selection — Filter substrates include SCHOTT BoroFloat® borosilicate, acrylic and Corning® Gorilla® Glass. Surface quality, parallelism and optical flatness can be selected according to the application.
- Coating & Mechanical Integration — Filters can incorporate compatible anti-reflection coatings, oleophobic coatings, VHB adhesive and protective films and can be supplied in threaded mounts, C-mounts, slip mounts, unmounted configurations or custom sizes.
- Fabrication & Spectral Verification — Filter production can combine glass selection, optical coating, glass fabrication, mounting and testing. Transmission and reflection scans can be used to verify the spectral response of the finished component.
Frequently Asked Questions
An optical bandpass filter transmits a defined wavelength range while blocking wavelengths outside that range. This allows the optical system to isolate useful signals while reducing unwanted background radiation or interference.
Available substrate options include SCHOTT BoroFloat® borosilicate, acrylic and Corning® Gorilla® Glass. The choice depends on optical, mechanical and environmental requirements.
Certain NIR / Dual Bandpass, UV Bandpass and Longpass filter configurations are available with 40/20 scratch-dig surface quality. Double-side polished substrates are also available where optical flatness and parallelism are important.
Depending on the filter type, configurations can include threaded mounts, C-mounts, slip mounts, unmounted filters and custom sizes.
Yes. Depending on the filter configuration, compatible options can include anti-reflection coatings, oleophobic coatings, VHB adhesive and protective films.
Request a Custom Optical Filter
Whether the application requires visible wavelength isolation, NIR sensing, UV filtering, IR rejection or a custom shortpass / longpass transmission window, the filter can be configured around the required spectral and mechanical parameters.
Send the wavelength requirement, transmission and blocking targets, angle of incidence, substrate, size and mounting configuration for review.