Vision Lighting, Lensing & Accessories
    Optical Filters

Optical Filters

Edmund Optics optical filters are used to selectively transmit or reject a wavelength or range of wavelengths. They are used in applications such as fluorescence microscopy, spectroscopy, clinical chemistry, or machine vision inspection and are ideal for life science, imaging, industrial, or defense industries. Edmund Optics offers a variety of filters for many applications, including bandpass interference, notch, edge, dichroic, color substrate or ND, as well as highly durable hard coatings for applications that require high optical densities with maximum performance.

Longpass Edge Filters

Longpass filters are designed to transmit wavelengths greater than the cut-on wavelength of the filter and are commonly used to isolate portions of the spectrum in a variety of industrial or life sciences applications including microscopy or fluorescence instrumentation. Longpass edge filters are typically designed for a 0° angle of incidence, whereas longpass dichroic filters are designed for use at a 45° angle of incidence. These filters can be used with shortpass edge and dichroic filters to create custom bandpass filters. Certain longpass edge filters can also be used as cold mirrors to minimize the heat buildup often caused by infrared radiation. Edmund Optics offers a wide variety of longpass edge and dichroic filters for performance in the ultraviolet, visible and infrared wavelengths. They are available in a range of optical densities, with higher optical densities offering increased blocking capability.

Optical Cast Infrared Longpass Optical Filters

These plastic filters are ideal for blocking visible light while passing near-infrared wavelengths. New plastic technology has produced filters with properties that can satisfy a variety of optical and environmental needs at half the weight of glass filters. Compared to similarly available transparent plastics, Thermoset ADC filters have the highest transmission and lowest haze, have at least 25-50 times greater abrasion resistance and are resistant to all types of chemicals and solvents (such as acetone, acids, alkali and alcohols). In addition to having excellent thermal characteristics, they are resistant to pits from hot sparks resulting from welding or grinding processes. They can also be easily drilled with high-speed carbide bits for all types of mounting.

Bandpass Optical Filters

Optical bandpass filters are used to selectively transmit a portion of the spectrum while rejecting all other wavelengths. They are ideal for a variety of applications, such as fluorescence microscopy, spectroscopy, clinical chemistry, or imaging. Edmund Optics offers a wide variety of these filters in a range of bandwidth options, including laser line filters, fluorescence filters, 10nm filters, hard-coated filters and traditionally coated evaporated filters. Optical bandpass filters are angular sensitive, so care should be taken when mounting or integrating into an optical system.

Shortpass Edge and Dichroic Filters

Shortpass edge and dichroic filters are used to transmit wavelengths shorter than the cut-off wavelength of the filter. Shortpass filters are typically designed for a 0° angle of incidence, whereas shortpass dichroic filters are designed for use at a 45° angle of incidence. Edmund Optics offers a variety of these filters for performance in the ultraviolet, visible or infrared spectrums. TECHSPEC OD 4 shortpass filters offer superior blocking with maximized transmission, while TECHSPEC dichroic shortpass filters feature low polarization dependence, broad spectral ranges and hard coatings ideal for use in harsh environments. Shortpass edge filter kits are also available.

Notch Optical Filters

Notch filters  selectively reject a portion of the spectrum, while transmitting all other wavelengths. These filters feature dielectric coatings to reflect laser wavelengths. Edmund Optics offers a range of notch filters that feature OD 4 or OD 6 blocking, or multi-notch capability. OD 4 notch filters feature narrow rejection bands of just ±2.5% of the center wavelength, while offering greater than 99% reflection of the designated laser wavelength. OD 6 notch filters are used in applications that require deep blocking of a narrow wavelength range, while offering broad transmission of the other wavelengths. Multi-notch filters are for applications that require the rejection of multiple narrow bands without the use of a multi-filter setup.

Neutral Density Filters

ND filters are often used in imaging or laser applications where excessive light can be damaging to camera sensors or other optical components. ND filters are also ideal for preventing excessive light from causing inaccurate results in photometer applications. These filters are designed to reduce transmission evenly across a portion of the spectrum by absorbing or reflecting the portion of the light that is not being transmitted. Edmund Optics offers a wide variety of ND filters for UV, visible or IR applications. ND filter kits are available and stepped ND filters are also available.

Machine Vision Filters

Machine Vision Filters are designed to improve the image quality and contrast in imaging or other machine vision applications. These filters are available in a variety of convenient mounted options to ease integration onto imaging lenses. They can be used to increase or decrease color temperature, block unwanted ultraviolet or infrared light, reduce overall light transmittance, or transmit light of a specific polarization state. Edmund Optics offers a wide variety of machine vision Filters for integration into a range of applications, such as inspection, robotics or factory automation.

Color and Absorptive Filters

Color and absorptive filters are available in longpass, bandpass and neutral density options. They are ideal for use as environmental displays or for other machine vision or industrial applications. These filters utilize the material’s inherent absorption or transmission properties, rather than interference effects from thin film coatings. By controlling the thickness of the material, precise filtering across large bandwidths can be achieved. Edmund Optics’ color and absorptive filters are available in glass, plastic, or film substrates. Glass filters offer high durability, while plastic or film filters are cost-sensitive alternatives.