Optical Filters: Characteristics and Applications

November 10, 2017

Optical filters are used to reflect, absorb, refract, or diffract specified wavelengths while allowing other wavelengths to pass through.

IRD Glass custom manufactures numerous optical filters that expand the applications and improve the capabilities of almost any optical component. We work with many different filter glass materials and have the capability to apply thin-film optical coatings, from UV through IR spectrum, in house.

What are Optical Filters?

Optical Filters are used to selectively reject or transmit a wavelength or selected range of wavelengths. With optical filters, light can be selectively blocked or transmitted based on certain properties, such as intensity or wavelength. Using advanced coating technology or filter glass or both, customized filters can be developed to meet nearly any requirement. Filters can also be combined to achieve a desired characteristic rather than manufacturing a new one.

With near-countless applications, you can find an optical filter in many industries, ranging from surveillance and defense to life sciences and spectroscopy. Optical filters are also used to identify gasses here on earth and in deep space, in medical imaging applications, and also in industrial and manufacturing settings, both to identify leaks and to assist in machine vision inspection.

Common Optical Filter Types

  • Long-pass filters – Long-pass filters transmit longer wavelengths above a specified range while minimizing shorter wavelengths.
  • Short-pass filters – Short-pass filters transmit shorter wavelengths over an active range while minimizing longer wavelengths.
  • Bandpass filters – A bandpass filter is a combination of a short-pass and a long-pass filter. The effect is a filter that has lower and more precise transmittance values because it rejects any wavelengths outside a predetermined range.
  • Thin-film optical filters – Thin-film filters can be customized to meet nearly any sort of transmission curve. They are used both to block laser light and in standard light control systems.

Production Quote, Prototype Request, or General Inquiry?

IRD Glass can provide optical filters for any application. We meet the needs of OEM customers needing everything from small runs and prototypes to high-volume production. For your convenience you can even upload specifications and drawings.

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