Sputtered interference filters

Custom Bandpass Filters, Sputtered and Diced in Rye

Kingsview Optical designs and makes custom bandpass filters by magnetron sputtering at our site in Rye, East Sussex. Tell us the centre wavelength, bandwidth and blocking you need, and we model the design, coat it, dice it to size and measure every batch, from prototype lots to repeat production.

  • Magnetron sputtered in Rye
  • Diced in-house
  • Every batch measured
  • ISO 9001:2015
Send Your Filter Spec See the Specification
Sputtered bandpass filter wafer diced into individual filters at Kingsview Optical
A sputtered bandpass wafer, diced into individual filters in Rye.
Filters made here, start to finish. Designed, sputtered, diced and measured at our site in Rye.
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The basics

What a Bandpass Filter Does

In short: a bandpass filter transmits one band of wavelengths and blocks the light either side of it. Three numbers describe it: the centre wavelength, the bandwidth (FWHM) and how deeply it blocks outside the band.

Our bandpass filters are interference filters. Dozens of thin, alternating layers of high and low index oxides set up interference that passes the design band and reflects the rest. Because the unwanted light is reflected rather than absorbed, the filter stays cool and the edges of the band can be made steep.

Magnetron sputtering packs each layer almost as densely as the bulk material. That keeps the passband where it was designed as humidity and temperature change, which evaporated filters can struggle with, and gives a hard surface that stands up to handling and cleaning.

The band moves to shorter wavelengths as the angle of incidence increases, and widens in a converging beam. Tell us the angle and cone angle in your system and we design for them. For UV bandpass filters in coloured glass, see our Schott UG filters.

SourceBandpass filterdesign band passesreflectedreflected
A bandpass filter transmits the design band and reflects the rest.
0%50%100%400450500550600650700Wavelength (nm)TransmissionBlocking (OD)Blocking (OD)FWHM (bandwidth)Centre wavelength (CWL)Peak transmission
Illustrative curve showing the figures you specify. Your filter is designed to your own numbers and measured on our Lambda 1050+.
Types

Bandpass Filters We Make

Every bandpass filter we make is designed around your system, not picked from a catalogue. These are the families most of our enquiries fall into.

TypeWhat it doesTypical use
NarrowbandA band from 10nm wide that isolates a single line or wavelength from a broad source.Spectroscopy, gas detection, line isolation
Laser lineA narrow band centred on a laser wavelength, with deep blocking to clean up the laser's side emission.Laser clean-up, Raman excitation, laser sensing
BroadbandA wide passband with steep edges, such as a single colour channel or the visible band only.Machine vision, colour separation, imaging
FluorescenceExcitation and emission filters matched to your fluorophores and light source, with deep blocking between them.Microscopy, diagnostics, life science instruments
Specify what mattersCentre wavelength, bandwidth and blocking all drive cost. A looser tolerance on one can pay for a tighter one on another, so tell us which numbers your system depends on.
Blocking to your detectorWe extend the blocking over the range your detector can see, for example out to 1100nm for silicon, so out-of-band light doesn't leak into the signal.
Made in Rye

How We Make Your Bandpass Filters

All four steps happen at our site in Rye, so you deal with one supplier, one purchase order and one lead time, from prototype lots to repeat production.

01DesignYour curve is modelled in Essential Macleod before anything goes in a chamber, so the quote comes with a target to measure against.
02SputterDense oxide multilayers deposited by magnetron sputtering at our site in Rye. Back-face AR added in-house if needed.
03DiceCoated wafers are diced to size on our Disco dicing saw for clean edges and full clear aperture. Glass can also be CNC edged to shape.
04MeasureEvery batch measured on a Perkin-Elmer Lambda 1050+. Measured-versus-design traces on request, with witness samples kept.
Applications

Where Our Bandpass Filters Are Used

Fluorescence and life scienceExcitation and emission filters for microscopes and diagnostic instruments.
Spectroscopy and analysersIsolating absorption lines in gas detection and chemical analysis.
Machine visionMatching the camera to an LED illuminator and rejecting ambient light.
Laser systemsCleaning up laser lines and rejecting stray light in sensors and rangefinders.
Defence and securityFilters for sights, sensors and surveillance optics, made under NDA.
Medical devicesWavelength selection in diagnostic and imaging equipment.
Specification

Bandpass Filter Specification

Every filter is designed to your numbers. These are typical figures; if your design needs tighter, tell us which parameter. We'll tell you plainly whether we can hold it, and what it adds to cost.

Centre wavelength tolerance±2nm
Bandwidth (FWHM)From 10nm to over 100nm
Passband transmissionTypically above 90% average, depending on design
BlockingUp to OD6, over the range your detector sees
Angle of incidence0° standard; other angles designed to order
Wavelength range300 to 3000nm, from the UV through the visible to the SWIR
SubstratesFused silica, borosilicate and optical glass; we can coat your own substrate
SizeCoated on wafers up to 100mm diameter; diced filters from 0.8mm square, or single filters up to 100mm
Dimension tolerance±0.1mm standard; tighter on diced parts on request
Surface quality (scratch-dig)60/40 standard, 40/20 on request
MeasurementEvery batch on a Perkin-Elmer Lambda 1050+, 200 to 3000nm; traces on request

Not sure what to specify? Tell us your light source, your detector and the wavelength you need to isolate. We'll suggest a centre wavelength, bandwidth and blocking that work, and send a modelled curve with the quote.

Questions

Bandpass Filter Questions

What does FWHM mean on a bandpass filter?
Full width at half maximum: the width of the passband measured at half the peak transmission. A filter centred at 550nm with a 10nm FWHM transmits at least half its peak from roughly 545 to 555nm.
How deep does the blocking go?
Blocking is quoted as optical density (OD). OD4 lets through 0.01% of the light and OD6 lets through 0.0001%. We can block to OD6, and we set the depth and range to suit your source and the wavelengths your detector responds to.
Why do sputtered filters stay on wavelength?
Sputtered layers are dense, so they take up very little moisture. Evaporated filters can shift wavelength as the humidity changes. Sputtered filters stay close to their design and are hard enough to clean.
Does the angle of incidence change the filter?
Yes. Tilting an interference filter moves its band to shorter wavelengths, and a converging beam widens it. We design for the angle and cone angle in your system.
Can you make prototype quantities?
Yes. We make prototype lots and repeat production from the same design, and keep witness samples so later batches can be checked against the first.
What do you need to quote a bandpass filter?
The centre wavelength, FWHM, blocking range and OD, minimum transmission, angle of incidence, size, thickness and quantity. A sketch of the curve is enough to start.

Related Filters and Coatings

Custom optical filtersAll our sputtered and coloured glass filters, and how we make them Notch filtersLaser line and Raman notch filters with clear passbands Longpass and shortpass filtersSteep edge filters, IR cut filters and hot mirrors Optical coating serviceAR, mirror and sputtered coatings applied in our own chambers

Getting a Quote for Custom Bandpass Filters

Send the spectral requirement, even as a sketch of the curve. An engineer from the team that would make your filters, not a sales team, will review it and tell you plainly what's achievable and what will drive cost.

What to send

  • Centre wavelength and bandwidth (FWHM)
  • Blocking range and optical density
  • Angle of incidence, cone angle and polarisation if relevant
  • Size, thickness and substrate preference
  • Quantities: prototypes and expected production volumes

What happens next

  1. An engineer reviews itWithin one working day, confirming it's achievable and flagging anything that will drive cost or lead time.
  2. We model it and quoteThe quote comes with a modelled target curve to measure against.
  3. We coat, dice and measureAll in Rye, with measured traces if you need them.
Start Your Filter RFQ

Need a Bandpass Filter That Isn't in a Catalogue?

That's what our sputtering chamber is for. Send the curve you need and we'll come back with a design, a price and a lead time.

Send Your Filter Spec Call 01797 226202
Made in Rye, East Sussex. NDA-friendly. Defence and security work welcome. ISO 9001:2015.