Edge Filters

Defining Boundaries in Light Control

Assorted edge filters with long-pass and short-pass profiles arranged on a neutral surface.

Andover Edge Filters

Precision Wavelength Separation for Advanced Optical Systems

Edge filters serve as highly effective optical components that provide a sharp transition between transmitting and reflecting regions of the spectrum. These filters come in two main varieties: Long Wave Pass (LWP) that transmit longer wavelengths while blocking shorter ones, and Short Wave Pass (SWP) that do the opposite. Each edge filter is characterized by three critical parameters:

  • Cut-on/off Wavelength: The wavelength at which transmission changes from high to low (or vice versa)
  • Slope: The steepness of transition between transmission and rejection regions
  • Rejection Level: The degree of attenuation in the blocking region

Andover Corporation utilizes advanced thin-film coating technologies to produce edge filters with exceptional performance characteristics. Our filters feature steep transition slopes, deep rejection, and high transmission in the pass region. By employing interference effects rather than absorption, these filters provide superior durability and thermal stability compared to traditional colored glass alternatives. With wavelength coverage from 300nm to beyond 1000nm and the ability to fine-tune cut-on/off points through angle adjustment, we can deliver edge filters precisely matched to your application requirements.

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Edge Filter Construction Technologies

Edge filters employ sophisticated thin-film coating designs that enable precise wavelength discrimination. Understanding the available options helps ensure optimal filter selection for your application:

Hard Oxide Coating Technology

Our standard edge filters utilize magnetron-sputtered hard oxide coatings deposited on precision optical substrates. This construction provides excellent environmental stability and durability while delivering:

  • Deep rejection (OD4 or better)
  • Sharp transition slopes (≤6% standard, ≤1% for steep-edge versions)
  • High transmission (>85% average in pass region)

Steep-Edge Technology

For applications requiring the sharpest possible wavelength discrimination, our steep-edge filters employ specialized coating designs that achieve:

  • Ultra-steep transitions (≤1% slope)
  • Exceptional transmission (≥91% average)
  • Superior blocking (OD4+)
  • Extended temperature range (-50°C to +200°C)
Our decades of experience in precision optical coating technology ensures you receive edge filters that deliver reliable, repeatable performance for your most demanding applications.

Edge Filters Product Solutions

Wavelength Discrimination with Industry-Leading Slopes and Transmission

From standard long and short wave pass filters to ultra-steep transitions, our edge filters deliver superior spectral control for your most demanding applications. Available in wavelengths from 300nm to beyond 1000nm with customizable cut-on/off points through angle tuning.

Assorted edge filters with long-pass and short-pass profiles arranged on a neutral surface.

Standard Long Wave Pass (LWP)

First-surface dielectric coatings providing high transmission of longer wavelengths while rejecting shorter ones. Ideal for order sorting and broad spectral isolation.
  • Wavelength Range 300-1000nm
  • Cut-on Slope ≤6% (11% for 300nm)
  • Transmission >85% average after cut-on
  • Operating Temperature -50°C to +100°C
Stock Availability
Angle Tunable
Cost Effective
Steep Edge Filters Andover Corporation

Steep-Edge Long Pass

Advanced magnetron sputtered hard oxide coatings offering the sharpest possible transition from blocking to transmission. Ideal for Raman spectroscopy and fluorescence applications.
  • Wavelength Range 325-700nm
  • Cut-on Slope ≤1% (2% for 325nm)
  • Transmission ≥91% average
  • Temperature Range -50°C to +200°C
Ultra-Sharp Transition
High Temperature
Premium Performance
Assorted edge filters with long-pass and short-pass profiles arranged on a neutral surface.

Standard Short Wave Pass (SWP)

Quarter-wave stack design optimized for transmitting shorter wavelengths while providing deep blocking at longer wavelengths. Perfect for laser line cleanup and fluorescence applications.
  • Wavelength Range 400-1000nm
  • Cut-off Slope ≤6%
  • Blocking Range 0.75x cut-off point
  • Substrate BK-7, Fused Silica
Deep Blocking
Durable
Standard Sizes

Frequently Asked Questions

Custom Optical Solutions

From prototype to production, our engineering team works with you to develop the perfect optical solution for your application.

Wavelength Range: Custom coatings from 193nm to 14μm

Multiple Technologies: Ion-assisted e-beam, magnetron sputtering, and hybrid solutions

Substrate Options: Various materials including germanium, silicon, and sapphire

Quality Assured: AS9100 and ISO 9001 certified processes

Tell us about your requirements, and our engineering team will help develop the optimal solution.

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