Bandpass Filters
Transmit a defined wavelength band while blocking wavelengths outside the passband.
Selective TransmissionPrecision Optical Filters
Precision optical filters for wavelength selection, blocking, attenuation and spectral separation across imaging, laser, sensing and analytical systems.
Filter Types
Spectral Control for Imaging, Laser and Sensor Systems
Filter selection begins with the required passband, blocking range, angle of incidence and optical density—not simply the filter color.
Longpass Filters
Block shorter wavelengths and transmit wavelengths above a specified cut-on edge.
Cut-On Filtering
Shortpass Filters
Transmit shorter wavelengths and block wavelengths above a specified cut-off edge.
Cut-Off Filtering
Neutral Density Filters
Reduce optical intensity with controlled broadband attenuation.
Broadband Attenuation
Notch Filters
Reject a selected narrow wavelength region while transmitting wavelengths on either side.
Narrowband Rejection
Dichroic Filters
Separate spectral bands by transmitting selected wavelengths while reflecting others.
Spectral Separation
Custom Optical Filters
Custom wavelengths, bandwidths, shapes, substrates and coating designs for application-specific systems.
Application-Specific DesignEngineering & Specifications
Specify the Spectral Requirement First
Filter performance depends on spectral edges, blocking depth, angle, polarization and operating environment.
Center / Edge Wavelength
Define center wavelength, FWHM, cut-on or cut-off wavelength as applicable.
Blocking Range
Specify the wavelength region that must be rejected and the required optical density.
Transmission
Define minimum in-band transmission and allowable ripple where relevant.
Angle of Incidence
Interference filters can shift spectrally with angle; specify the actual system geometry.
Substrate & Environment
Match substrate, durability and coating construction to wavelength and operating conditions.
Engineering recommendation: provide the full spectral requirement or source/detector information with the RFQ. Avoid specifying an unnecessarily narrow band or excessive blocking depth unless the system requires it.
Typical Applications
Optical Filters Integrated into Real Systems
Filters improve contrast, isolate signals and suppress unwanted wavelengths across laser, imaging, biomedical and analytical platforms.
Laser Systems
Laser-line isolation, harmonic rejection and beam diagnostics.
Machine Vision & Imaging
Contrast enhancement, color separation and ambient-light suppression.
Biomedical & Fluorescence
Excitation/emission separation and signal isolation in optical diagnostics.
Spectroscopy & Sensors
Spectral selection for analytical instruments, detectors and sensor systems.
Engineering Resources
Optical Filter Design Resources
Selection Guide
How to Select an Optical Filter
Compare filter functions by passband, blocking and system wavelength.
Read Guide → Engineering GuideOptical Density & Blocking
Understand blocking specifications and when higher OD is actually required.
Read Guide → Design GuideAngle of Incidence Effects
See why interference-filter spectra shift with system geometry.
Read Guide →FAQ
Optical Filter Frequently Asked Questions
What information is needed to quote a custom optical filter?
Provide the required passband or edge wavelength, blocking range, transmission, optical density, angle of incidence, size, substrate preference and quantity.
What is the difference between bandpass, longpass and shortpass filters?
Bandpass filters transmit a selected band; longpass filters transmit wavelengths above an edge; shortpass filters transmit wavelengths below an edge.
Why does angle of incidence matter?
Interference-filter spectral performance can shift with incidence angle, so the actual system angle should be included in the design requirement.
Can COE manufacture custom sizes and shapes?
Yes. Custom dimensions, shapes, substrates and spectral coating designs can be reviewed for manufacturability.
Custom Optical Filters
Have a Spectral Requirement?
Send the wavelength, transmission, blocking, angle, dimensions and quantity for engineering review.