Optical Filters

Source: Acton Optics & Coatings
Optical Filters

Acton Optics & Coatings offers bandpass, band rejection, long pass, neutral density, reflective, and solar blind filters for spectroscopy, elemental analysis, environmental monitoring, biotechnology instrumentation, space exploration, and in general research areas.

Bandpass Filters

Acton’s bandpass filters cover the wavelengths from 122 to 320nm with bandwidths covering 10nm up to 100nm. These filter types are well-suited for a wide variety of laser and analytical applications and are available in 0.5, 1, and 2-inch diameters, though custom sizes are also available.

These filter types can be purchased open-faced or covered and edge-sealed for wavelengths above 170nm with optional mounting rings.

Band Rejection Filters

Band rejection filters by Acton are available for the bright 393.4 and 396.9nm wavelengths of calcium and are manufactured to permit plasma-emission spectroscopy in the 170 to 370nm region with reduced calcium spectral interference. Analysis of As 193.7 nm, Zn 213.9 nm, Cd 226.5 nm, etc. in direct-reading emission spectrometers is permitted by average filter transmittance level of 60 to 70% in the 200 to 350-nm region. Transmittance of 80 ±10% is maintained from 450 nm to the NIR. Useful transmittance down to 170 nm is obtained by the use of UV-grade fused silica substrates. Transmittance at 395 nm is 4.0% or less.

Magnesium band-rejection filters are available for the Mg lines at 279.6, 280.3, and 285.2 nm. Filters designed to reject other wavelengths are available upon request.

Long Pass Filters

Long pass filters block specific short-wavelength ranges by way of reflection. They’re ideal for gas detection systems and other environmental or analytical monitoring systems that call for the differentiation of the shorter UV wavelengths from longer visible to NIR wavelengths.

Neutral Density Filters

Each of Acton’s neutral density filters are individually calibrated for transmittance at a series of wavelengths and supplied with a transmittance curve. VUV and UV ND4, ND5 and ND6 filters are supplied in anodized metal rings. Other neutral density filters are provided open-faced, with mounting rings available on request.

Reflective Filters

Acton multi-layer reflective filters are all dielectric, narrow-band reflectors that offer high reflectance at specific VUV through UV wavelengths while transmitting longer wavelength UV to IR light.

Solar Blind Filters

Originally designed for the space program, these unique "very broadband" UV and VUV filters are useful for isolating broad bands of UV or UV-VUV radiation, while rejecting visible light. Acton Research very broadband filters offer broadband transmittance properties, averaging 10-20% over the bands specified. Rejection is approximately 5x10-3 at 500nm.

Contact Acton Optics & Coatings for information on their optical filter offerings.