Dichroic Filters

09 Dec 2022

Knight Optical has range of dichroic filters as part of our stock catalogue, this include shortpass, longpass and bandpass types. These filters offer superior reflection and transmission spectral properties, whilst exhibiting minimal absorption.

• Our shortpass dichroic filters have a high transmission before the cut-off, and then a high reflection band after. Knight Optical currently offer shortpass dichroic mirrors with cut-off wavelengths ranging from 414nm to 730nm.
• Knight Optical’s longpass dichroic filters have transmission and reflection bands divided by the cut-on wavelength, wavelengths before this cut-on point are reflected, whilst the longer wavelengths are transmitted. Knight Optical offer longpass dichroic mirrors with cut-on wavelengths from 420nm up to 740nm.
• The bandpass dichroic filters will only transmit a certain waveband whilst blocking (in this case through reflection) the wavelengths either side. Knight Optical stock bandpass dichroic mirrors with passbands centred from 350nm to 850nm.
• Colour correction filters offer pure, true to life colour temperature adjustment for entertainment and photography. Knight Optical has daylight and tungsten conversions available.

Coated on borosilicate, a low thermal expansion glass, Knight Optical’s dichroic cut filters are available as stock items, either as 12.5mm or 25mm diameters or 50x50mm squares.

Please find our specifications below for our catalogue components:

Material: Borosilicate or equivalent

Diameter: +0.0 / -0.20 mm

Length/Width: ± 0.25 mm

Thickness: ± 0.20 mm

Surface Quality: < 60-40 scratch/dig

Wavelengths: 300-1200nm dependant on type

Wavelength Accuracy: +/-5nm

Transmission: Tmax=95% dependant on type and substrate

With large sheets available, we are also able to cut custom sizes for our customers. Typically, we produce diameters and squares to the following tolerances:

Available sizes: Square 7mm-300mm 

                            Diameter 10mm-400mm

Cutting tolerance: ± 0.2mm

However, we are also able to provide bespoke shapes to fit your requirements.

Fully customisable options are available upon request, including different thickness and customisation on the AR coating.

All filters are tested in our metrology department using our Cary 7000 spectrophotometer, and raw data and graphs can be provided to our customers, as well as dimensional reports.

Contact our technical account managers with your enquiries.