Perfecting Your Light ®


Linear Apodizing Coatings

linear apodizing filterA Linear Apodizing Filters (LAF)  is one type of a full line of apodizing filters. These Linear Apodizing filters are used to eliminate undesirable intensity variations in optical systems. The apodization filters have a fixed ND coating in one direction and a variable ND coating in the other direction. There are two basic types of these filters: 1) Dark in the center to clear on the outer edges, or 2) Clear in the center to dark on the outer edges.

The gradient function is typically customer defined to meet there specific optical requirements. The gradient function can be defined as a set of data points or a full algebraic equation such as: Linear, Gaussian, Exponential or Polynomial. A Linear Apodizing Filter can be designed to work in the UV, Visible, or the Far IR. The filters are made with metal coating and thus are able to be used in narrow or wide wavelength applications. These filters can be supplied with anti-reflection coatings on one or both sides to maximize transmission.

Key features include:

• Density gradients can be customized to suit most application
• The filter can be applied to a number of different substrate materials
• Can be designed to be used from the UV to the Far IR
• Corrects for non-uniformity in illuminations systems
• Eliminates detector saturation
• 35% maximum absorption
• Used for low power applications
• The filters are often used as soft slits to eliminate diffraction patterns in optical systems


• Entertainment: To make light distribution uneven for special effect applications.
• Imaging: To break up diffraction patterns by the introduction of soft edges.
• Industrial: To control the light emission from an automatic welding torch to a CCD camera to eliminate detector saturation.
• Military: To eliminate IR detector saturation in ground-to-air and air-to-air missiles optical systems.
• Scientific: Used as a variable phase plate when the gradient coating material has the same index of refraction as the substrate.
• Semiconductor: Used in photolithography exposing systems to obtain perfect illumination distribution.

We also offer custom Bullseye® Apodizing filters and in-stock Bullseye® Apodizing filters: clear in the center or dark in the center.

  Custom quotes are available.

  Articles found on Photonics Spectra