Edge Filters – Custom Specified

Product Description

Edge filters separate a broad spectrum of light into two components: a transmitted component and a rejected component. Unlike dichroic filters, edge filters may provide rejection through a combination of absorption and reflection and are not specifically designed to provide a useful reflection band. These filters are defined by either a cut-on or a cut-off slope establishing the transition between a region of high rejection and a region of high transmission. Cut-on and cut-off edges are typically defined by long wave or short wave pass filter coatings.

Long wave pass edge filters have a region of rejection on the short-wavelength side of the cut-on wavelength. This rejection region can be provided by an absorbing element such as colored glass, dyed epoxy, or other light absorbing element, or it can be provided by thin-film coatings. Conversely, short wave pass edge filters have a region of rejection on the long-wavelength side of the cut-on wavelength. Although some rejection on short wave pass filters can be provided by absorptive materials, the majority of the rejection is accomplished using thin-film coatings.

The majority of the edge filters that we manufacture are custom designed for OEM instrumentation for an extremely diverse set of applications ranging from agricultural automation to medical diagnostics. Working in partnership with the instrument manufacturer's optical engineers and scientists, we design custom long or short pass filters that are optimized for the instrument architecture and the analysis to be performed on it. This team approach enables delivery of the best cost / performance / time-to-market value to the instrument maker.

We make edge filters in several different configurations:

Single substrate, image quality, all-dielectric hard sputtered coating

Single substrate, general quality, all-dielectric hard sputtered coating

Multi-element, image quality, all-dielectric hard sputtered coating, laminated assembly

Multi-element, general quality, all-dielectric hard sputtered coating, laminated assembly

Multi-element, image quality, semi-hard thermally evaporated coating, laminated assembly

All of these configurations can deliver exceptional performance at economical cost. We recommend the best configuration given the requirements of the instrument.

Edge Filter Specification Checklist

The list of parameters that follows includes the most common items used to specify an edge filter. Many of the parameters are general enough to apply to any optical filter. Care should always be taken to avoid over-specification. For example, specifying some of the specifications in the optical category such as transmitted wavefront error can, depending on the chosen value, have a significant impact on cost while providing no increase in filter performance if the filter is used in a photometric detection application. When using this checklist, the best strategy is to provide what is known to be important and allow our technical team to recommend other specifications from the list that will insure the best performance for the application. After completing the checklist, please call 508-528-4411 to speak directly to one of our Technical Sales Engineers, or email us at filters.sales@newport.com to address your specific requirements.

Edge Filter Specification Checklist

Application
Operating Conditions
Operating Temperature
Storage Temperature
Angle of Incidence
System Speed
Detector
Illumination Source
Polarization State
 
 
Physical
Length / Length tolerance
Width / Width tolerance
Thickness / Thickness tolerance (or max)
Active Area (min)
Edge treatment-Bevel
Edge treatment-Ring
 
 
Optical
Surface Quality
Flatness (S1)
Flatness (S2)
Parallelism
 
 
Durability
Hardness
Adhesion
Humidity
 
 
Spectral
Cut-on wavelength (λ @ x% Tpk or λ @ x% abs)
Cut-on wavelength tolerance
Edge Steepness (%)
Transmittance band
%Tavg in transmittance band
Blocking band
Blocking (min OD / max %T over range)
 
 
Other