Filters

Filters are used to control the wavelength or intensity of light. The incredible breadth of filters available directly from CVI Laser Optics makes it easy to find the right balance between optical performance, laser damage threshold, reliability, and cost for your application. Our transmission filters include laser line, diode, and polarization bandpass filters with high throughput and blocking, as well as more economical interference filters. When an edge filter is needed, we have options ranging from color glass and basic long and short wave pass filters to ultra-steep longpass filters for Raman applications. We also understand how to block light, at a single wavelength with a notch filter, over a band with a color glass filter, or over a broad range of wavelengths with absorptive and high energy neutral density filters. We even have spectrophotometer calibration filters.

Our more than one thousand catalog filters span the full UV through NIR wavelength range, from 190 – 2000 nm. Many are antireflection coated for maximum transmission, and all are manufactured with the right mechanical and optical tolerances to satisfy the needs of your application without adding unnecessary cost.

If you require a filter in a different size or shape, on a special substrate, or with slightly different optical properties, we can help. We regularly produce custom filters for OEM customers in high volume, and will work with you to design a filter that is optimized for your system’s technical and cost requirements. We’ve produced some pretty sophisticated filters with multiple passbands and notches, and with deep and/or extended blocking. Our ultra-steep RazorEdge® set the industry standard for transition width and blocking. We can even produce custom neutral density filters, or create a custom filter set.

Capabilities

Standard Custom Options
Types
  • Laser line cleanup
  • Bandpass
  • Single notch
  • Long wave pass
  • Short wave pass
  • Schott color glass
  • Absorptive neutral density
  • Reflective neutral density
  • Polarization bandpass
  • Calibration standards
  • Multipass laser line cleanup
  • Multiple bandpass
  • Multiple notch
  • Custom filter sets
Materials N-BK7, UV-grade fused silica, Schott optical glass Optical crown glass, silicon, germanium
Dimensions 12.7 - 101.6 mm 2.0 to 150.0 mm
Coatings
  • e-beam dielectric
  • Thermal evaporation
  • Plasma ion-assisted
  • Magnetron sputtering
  • Ion beam sputtered
  • Inconel® neutral density
  • Low-loss antireflection
  • Other wavelengths (193 - 2100 nm)
  • Other bandwidths
  • Other angles of incidence
  • High OD, extended blocking
  • Ultra-high damage threshold
  • Far-infrared
Quality Standard, precision, and laser quality See manufacturing tolerances below

Filter Substrate Manufacturing Capabilities**

Surface Tolerances Precision Laser Quality High Precision
Surface Quality
(scratch - dig)
40 - 20 10 - 5 5 - 2
Surface roughness (Å, RMS) 20 5 1
Surface Figure
(P-V @ 633 nm before coating)
λ/2 λ/10 λ/25
Dimensional Tolerances Commercial Precision High Precision
Diameter (mm) +0.000 / -0.250 +0.000 / -0.100 +0.000 / -0.010
Length & width (mm) ± 0.050 +0.000 / -0.125 +0.000 / -0.010
Thickness (mm) ± 0.250 ± 0.100 ± 0.010
Angular deviation < 5 arc min ≤ 1 arc sec ≤ 0.5 arc sec
Centration (ETV, mm) 0.05 0.01 0.005
Clear Aperture ≥ 85% ≥ 90% ≥ 95%

** Note: The general tolerance specifications above are intended to guide determination of appropriate tolerances based both on relative cost and manufacturability. Part-specific tolerances will vary depending on size, material, shape and aspect ratio. Tighter tolerances may be possible, so please contact us to discuss your custom specifications. All specifications do not need to be from a single column, though trade-offs may be required in order to meet the desired combination of cost and performance.

Bandpass Filter Capabilities

Ultra-Narrow Standard Precision High Precision
Transmission > 90% > 90% > 95%
CWL tolerance 0.3% 0.2% < 0.1%
Bandwidth < 1% < 0.5% < 0.1%
Blocking 5 OD 6 OD 8 OD
Shape factor 20% 25% 40%
Standard Standard Precision High Precision
Transmission > 90% > 95% > 98%
CWL tolerance 0.5% 0.2% < 0.1%
Blocking 5 OD 6 OD 8 OD
Slope* 3% 2% < 1%
Shape factor** 20% 30% 50%
Multiband Standard Precision High Precision
Transmission > 90% > 95% > 98%
CWL tolerance 1% 0.5% < 0.1%
Blocking 5 OD 6 OD 8 OD
Slope* 3% 2% < 1%
Shape factor** 20% 40% 70%

* Slope = (0.3 OD point – 6 OD)/CWL

** Shape factor = 3 dB BW/ 6 OD BW

Notch Filter Capabilities

Ultra-Narrow Standard Precision High Precision
Transmission > 90% > 90% > 95%
Blocking bands
1 1 1
Bandwidth < 4% < 3% < 2%
Blocking 5 OD 6 OD 7 OD
Standard Standard Precision High Precision
Transmission > 90% > 95% > 98%
Blocking bands
1 1 1
Bandwidth
< 6%
< 5%
< 2%
Blocking
5 OD 6 OD 8 OD
Multinotch Standard Precision High Precision
Transmission > 80% > 85% > 90%
Blocking bands
2 3 4
Bandwidth
< 6%
< 4% < 3%
Blocking
4 OD 5 OD 6 OD

Edge Filter Capabilities

Ultra-Steep Standard Precision High Precision
Transmission > 90% > 90% > 95%
Tx ripple*
10% 5%
2%
Slope**
5% 3% 1%
Blocking 4 OD 5 OD 6 OD
Standard Standard Precision High Precision
Transmission > 90% > 90% > 95%
Tx ripple*
5%
2%
1%
Slope**
5% 1% 1%
Blocking 4 OD 6 OD 7 OD
Multi-Edge Standard Precision High Precision
Transmission > 00% > 90% > 95%
Tx ripple*
10%
5% 2%
Slope** 5% 3% 1%
Blocking 2 OD 3 OD 4 OD