Dimensions:

Specification:

*Manufacturer's data. A few items may have more cavities than standard, hence lower ratios.

‡Some filters have 5 cavities, see extra-broadband range. Filters with 5 cavities will have the same bandwidth ratios as the broadband range.

Technical notes

• To estimate the transmittance near the passband, use the bandwidth ratios given in the specification chart: e.g. 340 IL 12 has HBW = 10; for IL range 1%BW/HBW = 1.99, so 1%BW = 19.9; i.e. transmittance will be 1% of peak (about 0.3% absolute) at 340 ± (19.9/2), i.e. about 330nm and 350nm.
• For light incident at an angle the centre wavelength λ_o will shift to:
  
                                λ_Θ=λ_o(1 - k sin²Θ)
  
  where k is approximately 0.24 for IW and 0.11 for all others.
• The CWL shifts toward longer wavelengths with increasing temperature, at about 0.01nm/K

• Mounting in camera filter rings (See camera lens and camera filter holders)

For more details of your modification needs please enquire.

Boxed filter sets

Sets are supplied complete with a wooden storage box, at a discount on the individual filter prices. Items included in sets are marked in the tables.

01 IL 12                        - 10nm bandwidth
01 IL 25                     - UV, visible sets
01 IL 50     10mm     -    (10 filters)

02 IL 12     12.5mm   - 10-18nm bandwidth
02 IL 25     25mm      -  IR sets (10filters)

01 IU 12     12.5mm   - 40nm bandwidth sets
01 IU 25     25mm      -      (10filters)
01 IU 50    50mm      -

01 IW 10
01 IW 25    25mm     -    set (10 filters)

Custom sets:  Order 10 or more different interference filters in the same size and we will supply a wooden storage box free of charge.

Interference filter glossary

Bandwidth (HBW, FWHM): Width of the passband; specifically, the difference between the two wavelengths at which the transmittance is half the peak value. Similarly, 10% bandwidth (10%BW) is measured between points where T=10% of the peak, etc.
Blocking: Rejection of energy outside the pass-band.  Absolute blocking is the transmittance level not exceeded at any point in the specified wavelength range. Average blocking is a value averaged over the range.
Cavity:  The basic element from which a filter is constructed, consisting of two reflective coating stacks with a spacer layer between. Our standard range is based in a series of three cavities, all deposited as a single stack of layers.  Wider-band filters have more cavities and therefore a squarer shape of passband.
Centre wavelength (CWL): The wavelength midway between the half-power points which define the bandwidth.
Transmittance (T): The typical value of the peak transmittance of the filter (not necessarily occurring at the centre wavelength)