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Future of
Optical Filters

As light sources, digital sensors, and coating chamber technologies continue to improve, optical filters will naturally evolve and continue to advance. Optical filters are critical for some of the most demanding applications in automation, energy, medical imaging, security, and multi-element optical systems.

These advancements require developments on new substrates such as flexible thin film polymers and IR grade materials including silicon and germanium, or with new chemicals and compounds that yield high transmission and high blocking filters in the UV and IR spectrums. Advancements in coating chamber technology have resulted in higher precision filters yielding bandwidths of <1nm with tolerances of <1%, which truly pushes the limits of top of the line spectrophotometers. With each advancement, tolerances and specifications have been further optimized to better represent a precision substrate with improved surface quality, surface flatness, parallelism, and transmitted wavefront.

New materials, sub-nanometer specifications, deep UV to far IR spectral coverage, and various improved tolerances will continue the advancement of optics and photonics in nearly every consumer and scientific application.

Ultra-Narrow Designs

Ultra-Narrow Designs

For many years, laser line filters have featured bandwidths as narrow as 1.5 – 2nm, but with new advancements in coating technology and metrology, laser line filters can now achieve bandwidths of <1nm across the visible spectrum. This precision will greatly benefit single photon, Raman, and other imaging applications that detect very subtle and weak signals.

Figure 1 (left): Transmission plots for 355nm and 533nm Ultra-Narrow Bandpass Filters

Broadening Spectral Range

Broadening Spectral Range

Hard coated filters are primarily used to focus on the Visible and NIR spectral regions from around 400 – 1800nm. Recent advancements and technological developments in coating and material design have broadened this range into the UV and IR regions as low as 250nm and as high as 7300nm.

Figure 2 (left): Transmission plot for the 7.30µm, 25mm Diameter, Infrared Longpass Filter (#68-656)

Broadening Spectral Range

Thin, Flexible Materials

Ultra-thin, flexible filters are achieved using a unique extrusion process and feature a polymeric material design with thicknesses as small as 200µm. These filters are also scratch insensitive and flexible, allowing for unmet integration into some of the most complex form factors and compact optical systems.

Figure 3 (left): Structure of All-Polymer Flexible Filters

Tighter Tolerances and Specifications

Sputtering platforms used to coat filters involve hazardous temperatures, pressures, and particles moving at very high speeds. Ensuring a clean, pristine, and flat filter surface can therefore prove very challenging. Surface specifications such as parallelism, surface quality, surface flatness, transmitted wavefront, and power or irregularity typically suffer in traditional magnetron and ion-beam sputtering platforms; advancements in these techniques will lead to filters with tighter surface tolerances.

Figure 4 (right): EO Sputtering Platform Used to Coat Optical Filters

Tighter TOlerances

EO Next Generation of Optical Filters

Edmund Optics® continually improves our specifications and tolerances on our optical filters. The list below shows some of our newly improved optical filter capabilities.


Surface Quality of 20-10


Surface Flatness of λ/10 P-V


Transmitted Wavefront of λ/20 RMS


UV wavelengths as low as 250nm and IR wavelengths nearing 4000nm


Filters with thicknesses as low as 200µm

Figure 4: Surface and Wavefront Maps of a TECHSPEC® High Performance Fluorescence Dichroic Filter

View Optical Filter Product Families

TECHSPEC® High Performance Fluorescent Dichroic Filters

TECHSPEC® High Performance OD 4 Longpass Filters

TECHSPEC® High Performance OD 4 Shortpass Filters

TECHSPEC® High Performance OD 4 Shortpass Filters


FAQ  Does Edmund Optics® offer filters made from thin, flexible materials?
Yes, Edmund Optics® offers a line of Ultra-Thin Longpass Filters made from ultra-thin polymer layers. They are scratch insensitive and have thicknesses ranging from 200-500µm.
FAQ  What is the largest diameter filter available from Edmund Optics®?

The largest diameter filters that Edmund Optics® can produce are 300mm. Tolerances and uniformity become a concern on substrates this large due to sputtering and coating limitations.

FAQ  What are some of the most common filter substrates?

Common filter substrate materials include fused silica, N-BK7, and float glasses. Recently a trend towards fluoride materials, IR crystalline materials like silicon and germanium, and polymers and plastics has emerged.

FAQ  How do I select the right filter for my application?

The first step is to determine what type of filter is required for the application. The basic types of filters are shortpass, longpass, bandpass, dichroic, notch, and neutral density. Each type of filter has unique characteristics that lend better to one application or another. The second step is to determine what wavelengths are required, as filters are defined by what part of the spectrum they pass or do not pass. For instance, an UV Cut-Off (or Longpass) filter is designed to pass both the visible and IR portions of the spectrum, but block (or "cut") the UV portions of the spectrum.

FAQ  What happens when an optical filter is tilted?
Generally, as the angle of incidence increases a filter's transmission curve will shift to lower wavelengths. The effect of large angles from the center of the optical system is the same as tilting a filter from a perpendicular position to an optical system. As the angle of tilt gets larger, the curve will start to change shape, causing the transmission to steadily drop and the transmission curve slope to change. A similar effect is noticed as temperature increases. Interference filters are the most sensitive to angle of incidence and temperature.
FAQ  What types of filters can Edmund Optics® manufacture?
Edmund Optics® manufactures fluorescence, dichroic, narrow bandpass, multi-bandpass, notch, neutral density, shortpass, and longpass filters. If our standard filter selection does not meet your requirements, please contact us about custom solutions.


Application Notes

Technical information and application examples including theoretical explanations, equations, graphical illustrations, and much more.

Optical Filters

Optical Filter Orientation

Custom Bandpass Filter using Shortpass and Longpass Filters

Fluorophores and Optical Filters for Fluorescence Microscopy


Informative corporate or instructional videos ranging from simple tips to application-based demonstrations of product advantages.

What’s New in Optical Coatings: Introduction

Optical Filter Coatings: Comparison of Traditional and Hard-Sputtered

Related Pages

Additional webpages that describe related products, capabilities, or concepts.

Flexible Longpass Filters
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