Optical Filters

Optical Filters

Optical filters allow a portion of the spectrum to pass (transmit) whilst blocking the remainder. The simplest types of filter are made of absorptive materials such as doped glasses like OG550 and RG715 these glasses rely on the glass absorping certain wavelengths of light. The more complex and higher performing interference filters or dichroic filters use multiple layers of dielectric materials deposited on a substrate causing constructive/destructive interference of the light in order to achieve the required performance.

Click below for details on

There are three basic forms that Optical filters take:

Longpass Filter Graph

Longpass filters which block light at lower wavelengths and then transmit light from a specified cut-on wavelength.


Shortpass Filter Graph

Shortpass filters which transmit light at lower wavelengths and then block light from a specified cut-off wavelength.


Bandpass Filters Graph

Bandpass Filters transmit only a band or portion of the spectrum blocking all other wavelengths.


Optical filters are used in many applications including Fluorescence Microscopy. Glen Spectra supply an extensive range of filter sets and components specifically for this application, click here for details.

In addition we have also introduced a range of filters called 3rd Millennium Filters which allow the selection of cut-on and cut-off wavelength to be selected, a Pick n Mix system. The superior spectral performance and longer filter life of these filters make them ideal for use in optical instruments. These new filters comprises LP(Longpass Filters), SP(Shortpass Filters) and bandpass filters.

More general information about our Optical Filters.