Interference band-pass filters These Interference Band pass Filters are used to isolate and transmit a narrow wavelength that is required and block all other wavelengths through reflection. This range of Interference Band pass Filters consist of an all-dielectric coating along with other coatings for additional blocking and cemented together to form a stack. The individual filters are mounted in nested rings, providing a labyrinth epoxy edge seal for greatly extended life. Although these are mounted, unmounted type can be supplied at special request. These Interference Band pass Filters are all typically 3-7 cavity. Uses include line selection, laser signal selection, colorimetry and fluorimetry. They can also be used for imaging. When using high powers the reflective side must be towards the incoming light.
Knight Optical > Filters > Interference band-pass filters > Standard range (10nm bandwidth) > 25 diameter (mm) Only UK and EU customers are charged VAT at 17.5%, customers outside the EU and EU customers based outside the UK who have a valid EU VAT number will not be charged VAT Bulk Discounts! Where (B) appears next to a price below, bulk prices are available, click the (B) button to view! PDF Part No. Wavelength (CWL nm) Bandwidth (HBW nm) Peak transmission (%) Price Qty Buy 254FIB25 254.7 8 20 £168.00 330FIB25 330 10 25 £79.50 337FIB25 337.1 10 25 £79.50 340FIB25 340 10 30 £66.00 350FIB25 350 10 30 £79.50 355FIB25 355 10 30 £79.50 360FIB25 360 10 35 £79.50 365FIB25 365 10 35 £66.00 370FIB25 370 10 35 £79.50 380FIB25 380 10 45 £53.20 390FIB25 390 10 45 £53.20 400FIB25 400 10 45 £54.50 405FIB25 405 10 45 £53.50 410FIB25 410 10 45 £54.50 420FIB25 420 10 45 £54.50 430FIB25 430 10 45 £54.50 436FIB25 435.8 10 45 £54.50 440FIB25 440 10 45 £54.50 450FIB25 450 10 45 £54.50 458FIB25 457.9 10 45 £47.50 460FIB25 460 10 45 £47.50 470FIB25 470 10 45 £47.50 480FIB25 480 10 45 £47.50 488FIB25 488 10 45 £47.50 488FIJ25 488 10 70 £68.00 490FIB25 490 10 45 £47.50 500FIB25 500 10 50 £47.50 510FIB25 510 10 50 £47.50 515FIB25 514.5 10 50 £47.50 515FIJ25 514.5 10 75 £68.00 520FIB25 520 10 50 £47.50 530FIB25 530 10 50 £47.50 532FIB25 532 10 50 £47.50 540FIB25 540 10 50 £47.50 543FIB25 543 10 50 £47.50 546FIB25 546.1 10 50 £47.50 550FIB25 550 10 50 £47.50 560FIB25 560 10 50 £47.50 570FIB25 570 10 50 £47.50 578FIB25 577.7 10 50 £47.50 580FIB25 580 10 50 £47.50 589FIB25 589.6 10 50 £47.50 590FIB25 590 10 50 £47.50 600FIB25 600 10 50 £47.50 610FIB25 610 10 50 £47.50 620FIB25 620 10 50 £47.50 630FIB25 630 10 50 £47.50 633FIB25 632.8 10 50 £47.50 633FIJ25 632.8 10 75 £68.00 636FIB25 636 10 50 £47.50 640FIB25 640 10 50 £47.50 645FIB25 645 10 50 £47.50 650FIB25 650 10 50 £47.50 656FIB25 656.3 10 50 £47.50 660FIB25 660 10 50 £47.50 670FIB25 670 10 50 £47.50 680FIB25 680 10 50 £47.50 690FIB25 690 10 50 £47.50 694FIB25 694.3 10 50 £47.50 700FIB25 700 10 50 £47.50 710FIB25 710 10 50 £47.50 Knight Optical > Filters > Interference band-pass filters > Standard range (10nm bandwidth) > 25 diameter (mm)
Dimensions   Diameter: +0,-0.3mm Thickness: 5-6mm Clear aperture:   12.5mm dia. 8.6mm 25mm dia. 19mm 50mm dia. 44mm   Specification
Range Fin FIB (<1100nm) FIB (=1100nm) FIJ FIR FIW CWL tolerance (nm) +0.7,-0.4 ±2 ±3 ±2 ±5 ±7 HBW tolerance (nm) +0.7 ±2 ±3 ±2 ±5 ±8 Bandwidth ratios*             10%BW/HBW 1.74 1.35 1.74 1.35 1.13 1.05 1%BW/HBW 3.21 1.99 3.21 1.99 1.30 1.18 0.1%BW/HBW 6.09 2.92 6.09 2.92 1.60 1.36 0.01%BW/HBW 12.68 4.41 12.68 4.41 2.04 1.69 Blocking type and specification Induced transmittance filter10?? absolute, 200-3500+ Dielectric stacks:10?? ave,10?³ abs, x-ray to 1150nm No of cavities (min) 2 3 2 3 5 7
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 peak, etc. Blocking: Rejection of any energy outside the passband. Absolute blocking is the transmittance level not exceeded at any point in the specified wavelength range. Average blocking is a value averaged over a range. Cavity: The basic element from which a filter is constructed, consisting of two reflective coating stacks with a spacer layer in between. Our standard range is based on a series of three cavities and therefore a squarer shape of passband. Centre wavelength (CWL): The wavelength midway between the half-power points which define bandwidth (se above) Transmittance (T): The guaranteed minimum value of peak transmittance of the filter (not necessarily occurring at the centre wavelength) Technical Notes To estimate the transmittance near the passband, use the bandwidth ratios given in "specifications" e.g. 340FIB12 has HBW-10; for FIB range 1%BW/HBW=1.99,so 1%BW-19.9; .e transmittance ill be 1% of pea (about 0.3% absolute) at 340nm ±(19.9/2), i.e. about 30nm and 350nm. For light incident at an angle the centre wavelength ?o (1-k sin²?) where k is approximately 0.24 for FIW filters and 0.11 for all others. The CWL shifts towards the longer wavelengths with increasing temperature at about 0.1nm/K.