Interference filters used in a variety of applications in the UV, VIS & IR spectrums.
Optical Filter Fabrication
There are perhaps about as many types of glass filters as there are applications for them. Yet despite all the variety, one thing is clear: Sydor Optics offers exceptional manufacturing capabilities when it comes to custom optical filters. With the largest collection of double-sided grinding and polishing machines in North America, Sydor Optics can precisely fabricate custom filters to meet your exact requirements, from basic prototyping to high-volume production and every step in between. While color glass filters can be ordered directly from the original manufacturer, standard surface flatness and transmitted wavefront tolerances may not meet your precision requirements which is why Sydor Optics double-sided polishing process stands out.
Sydor Optics has extensive experience manufacturing uncoated filter substrates and colored filter glass. Common optical filters include shortpass, longpass, bandpass, notch and edge with filter coatings suited for the infrared (IR), ultraviolet (UV) and visible (VIS) color spectrums.
Our capabilities include:
High-Volume Capabilities
Custom manufacturing of uncoated filters
Available in a variety of materials and sizes
Available Optical Substrate Types
Based upon customer demand, Sydor Optics offers Optical Filters made from the following substrate materials. Of course, if you don’t see a material you need, please contact a Sales Engineer, who will gladly discuss additional options that may be available.
Color Filter Glass
Colored filter glass is available in a range of spectral characteristics each suited to unique transmission and absorption properties of various wavelengths of light.
Borosilicate glass, also called display glass, offers a combination of excellent light transmission and impressive technical properties. Made of silicon oxide and boron oxide, display glass is easily laser- or CNC-machined. In addition to having excellent chemical resistance, the material possesses a low coefficient of thermal expansion, meaning that it can resist high temperatures without cracking.
Fused Quartz is made using high quality, natural quartz powders with several fusion methods. Quartz material is stronger than glass, can be used at high temperatures (<1050°C) and has a high average transmission of over 80% from 260nm to 2500nm. The various qualities of fused quartz allow for use in a wide range of applications from semiconductor applications to lower precision window applications in hostile environments.
Fused silica is a transparent glass formed by melting and cooling pure silica sand. Unlike most other glasses, fused silica does not contain any additives. It is an amorphous solid with a purity that gives it excellent optical transmission.
Optical glass is known for its high transmission, low dispersion, and homogenous refraction indices. These properties result from the continuous melting process and subsequent finishing methods used to create optical glass.
This material is categorized into either flint glass or crown glass. Flint glass has an Abbe number < 55 and generally < 50. Flint glass is denser due to the inclusion of various metal oxides and exhibits strong chromatic dispersion. Crown glass has an Abbe number> 50 and generally > 55. Crown glass is typically less dense resulting from higher usage of alkali metals and exhibits low chromatic dispersion.
Transmitted Wavefront Error (TWE)* – before coating
> 1/20 wave over clear aperture
Optical Density Tolerance (uncoated)
± 0.01 OD
Optical Density Tolerance (coated)
± 0.03 OD
Clear Aperture
≤ 95%
Types of Optical Filters
Color Filters
Color glass filters are fabricated to selectively transmit a particular range of wavelengths or colors of light. In designing color filters to transmit a particular range, they’re also designed to block other wavelengths or colors. Sydor Optics can fabricate custom color filters to allow long wavelengths to pass (longpass), or short wavelengths (shortpass), or both (bandpass).
Dichroic Filters
Sydor Optics fabricates dichroic filters to transmit a particular range of the spectrum (the passband) while reflecting another range (known as the rejection band). Dichroic filters are commonly used for color separation in digital projection and CCD imaging. Sydor Optics can handle the custom fabrication of even the most complex dichroic filters.
Bandpass Filters
Bandpass filters are basically designed to selectively transmit a particular spectrum range and reject the other wavelengths. Bandpass filters are commonly used in a variety of applications, including chemistry, fluorescence microscopy, high-speed optical imaging, and spectroscopy.
Longpass Filters
As their name implies, longpass filters are designed to allow only long wavelengths to pass while blocking shorter wavelengths of light.
Shortpass Filters
Shortpass filters are a type of edge filter, designed to isolate desired wavelengths in the spectrum, and “cut” undesired wavelengths out of the optical system.
Notch Filters
Notch filters can be fabricated to the most demanding specifications for use in laser-based fluorescence, multi-photon microscopy, and Raman spectroscopy, and other high-speed imaging applications. As with other types of optical filters, Sydor Optics can fabricate custom notch filters to meet your specific needs and applications.
Edge Filters
As with other kinds of optical filters, edge filters are designed to separate a broad spectrum of light into light that is transmitted, and light that is rejected, or blocked. Edge filters can be used to reduce harmonics and light scatter and can be fabricated to function as longpass, shortpass, or bandpass filters.
Neutral Density (ND) Filters
Neutral density filters can be used to reduce the intensity of light by reflecting or absorbing a percentage of light at a specific wavelength. Neutral density (ND) filters reduce light intensity by absorbing or reflecting light and provide even attenuation across the specified wavelengths.
Infrared (IR) Filters
Infrared filters allow for high transmission in the IR spectrum and strong rejection to isolate even the narrowest band of wavelengths. As their name implies, IR filters can be fabricated for use in the harshest environments in FLIR, security, environmental and other infrared applications.
Ultraviolet (UV) Filters
Ultraviolet (UV) filters are used to block ultraviolet light (UV blocking), but allow visible light to pass. Sydor Optics can fabricate custom UV filters to meet your specific needs and applications including combining UV filters with other (bandpass/longpass) optical filters.
Broadband Filters
While certain kinds of optical filters are used to narrow wavelength ranges, broadband filters are designed to do the opposite: provide exceptional transmission throughout a broad range of wavelengths (but still exclude or reject the rest). Sydor Optics can fabricate custom broadband filters in various shapes and sizes to meet your specific needs and applications.
Filter Substrates
Sydor Optics can also manufacture filter substrates for you to coat. Our double-sided grinding and polishing machines allow for filter substrates created precisely to your specifications and are ideal for third-party coating.
Available materials for filter substrates include fused silica, display glass, low expansion, and optical glass. Please contact a Sales Engineer who will be happy to discuss all options for filter substrates.
Filter Shapes
Sydor Optics can manufacture custom optical filters — with various shapes and sizes — using CNC Glass Machining capabilities to meet your specific needs.
Some of the standard optical filter shapes that Sydor Optics customers frequently order include:
Circular Filters
Square Filters
Rectangular Filters
Elliptical Filters
Optical Filter Applications
Cinematography
Clinical Chemistry
Laser Systems
Machine Vision
Microscopy
Signal Attenuation
Spectroscopy
If you are starting a new program or need assistance, please contact us.
High-Volume Capabilities 
