Optical Bandpass Filters

Optical Bandpass Filters are spectrally selective components capable of transmitting specific wavelengths of light while blocking others. These filters are fully customizable in terms of center wavelengths and bandwidths, making them suitable for a wide range of applications, including fluorescence spectroscopy, microscopy, and flow cytometry. Optical Bandpass Filters provide consistent optical filter functions across the entire clear aperture. In contrast, Continuously Variable Filters offer a filter function that varies along one dimension of the filter.

Delta Optical Thin Film are pioneers and innovators in the design and manufacture of robust optical thin film components for a broad range of volume applications. We have designed and manufactured optical interference bandpass filters since the early 1970’ties.

Most of our products are custom designed filters and the examples we show on this webpage are just for inspiration. We often find benefits for our customers in a custom designed solution. Delta Optical Thin Film is focusing mainly on optical bandpass filters with passbands in the range from 300 nm to 1200 nm.

Choose from a large range of existing bandpass filters

Narrow bandpass, Broad bandpass, Laserline, TopPride™ – or get your own custom design made
Delta Optical Thin Film manufactures Bandpass Filters using either Plasma Assisted Evaporation Technology or Magnetron Sputtering Technology, depending on our customers’ requirements. On this web site you can find examples of optical Bandpass Filters we have already designed and manufactured.

The data sheets show actual measurements (not design curves) with typical transmission curves for unpolarized light and an AOI=0°.

As we often can optimise design and manufacturing methods to the individual application, please get in touch to discuss how we can best help facilitating your application.

If you cannot find the Bandpass Filter you need among our standard products, please do not hesitate to contact us to discuss your requirements. When specifying your filter, our technical note on specifying optical filters will help you avoid the main cost drivers in filter design.

Product specifications

λcenter (nm)FWHM (nm)Tpeak (%)Product numberMax size Data sheet
3651245LF101653Round diameter 25 mm x 2 mmDownload_15px
3655045LF101581Round diameter 25 mm x 2 mmDownload_15px
3772880LF101840Round diameter 25 mm x 2 mmDownload_15px
4361050LF101532Round diameter 25 mm x 2 mmDownload_15px
4455065LF101582Round diameter 25 mm x 2 mmDownload_15px
4646093LF104547Round diameter 25 mm x 2 mmDownload_15px
4703580LF101830Round diameter 25 mm x 2 mmDownload_15px
4704075LF101607Round diameter 25 mm x 2 mmDownload_15px
4704065LF101881Round diameter 25 mm x 2 mmDownload_15px
4704089LF101785Round diameter 25 mm x 2 mmDownload_15px
4704093LF10453980 mm x 55 mm x 1 mmDownload_15px
4753092LF101157Round diameter 25 mm x 2 mmDownload_15px
4754075LF102060Round diameter 25 mm x 2 mmDownload_15px
4804075LF101533Round diameter 25 mm x 2 mmDownload_15px
48022093LF10455180 mm x 55 mm x 1 mmDownload_15px
5002065LF101209Round diameter 25 mm x 2 mmDownload_15px
5051693LF10454080 mm x 55 mm x 1 mmDownload_15px
5255075LF102018Round diameter 25 mm x 2 mmDownload_15px
5255092LF121787Round diameter 25 mm x 2 mmDownload_15px
5261493LF10454180 mm x 55 mm x 1 mmDownload_15px
5305080LF102062Round diameter 25 mm x 2 mmDownload_15px
5354580LF101969Round diameter 25 mm x 2 mmDownload_15px
5355075LF101752Round diameter 25 mm x 2 mmDownload_15px
5405085LF101535Round diameter 25 mm x 2 mmDownload_15px
5452575LF101885Round diameter 25 mm x 2 mmDownload_15px
5461270LF101592Round diameter 25 mm x 2 mmDownload_15px
5461292LF103015Round diameter 25 mm x 2 mmDownload_15px
55010092LF101158Round diameter 25 mm x 2 mmDownload_15px
55019090LF103000Round diameter 25 mm x 2 mmDownload_15px
55520090LF102851Round diameter 25 mm x 2 mmDownload_15px
5581493LF10454880 mm x 55 mm x 1 mmDownload_15px
5585580LF100924Round diameter 25 mm x 2 mmDownload_15px
55829594LF10455280 mm x 55 mm x 1 mmDownload_15px
5604075LF101537Round diameter 25 mm x 2 mmDownload_15px
56010085LF101450Round diameter 25 mm x 2 mmDownload_15px
5653075LF101420Round diameter 25 mm x 2 mmDownload_15px
570790LF101632Round diameter 25 mm x 2 mmDownload_15px
5722592LF101708Round diameter 25 mm x 2 mmDownload_15px
5791693LF10454280 mm x 55 mm x 1 mmDownload_15px
5872592LF101757Round diameter 25 mm x 2 mmDownload_15px
5922480LF101712Round diameter 25 mm x 2 mmDownload_15px
6057085LF102020Round diameter 25 mm x 2 mmDownload_15px
6078092LF101706Round diameter 25 mm x 2 mmDownload_15px
6086585LF101599Round diameter 25 mm x 2 mmDownload_15px
6121293LF10454580 mm x 55 mm x 1 mmDownload_15px
61811585LF100920Round diameter 25 mm x 2 mmDownload_15px
6221480LF100968Round diameter 38 mm x 2 mmDownload_15px
6306092LF101710Round diameter 25 mm x 2 mmDownload_15px
6307580LF101207Round diameter 25 mm x 2 mmDownload_15px
6321293LF10454380 mm x 55 mm x 1 mmDownload_15px
6403080LF101659Round diameter 25 mm x 2 mmDownload_15px
6421680LF101523Round diameter 25 mm x 2 mmDownload_15px
6477092LF101758Round diameter 25 mm x 2 mmDownload_15px
6611293LF10454480 mm x 55 mm x 1 mmDownload_15px
6681485LF100971Round diameter 17,9 mm x 2 mmDownload_15px
67036095LF10455380 mm x 55 mm x 1 mmDownload_15px
67510090LF101714Round diameter 25 mm x 2 mmDownload_15px
6811693LF10454680 mm x 55 mm x 1 mmDownload_15px
6905080LF101658Round diameter 25 mm x 2 mmDownload_15px
7071680LF101727Round diameter 25 mm x 2 mmDownload_15px
7221480LF101650Round diameter 25 mm x 2 mmDownload_15px
7314093LF10454980 mm x 55 mm x 1 mmDownload_15px
7704080LF101729Round diameter 25 mm x 2 mmDownload_15px
77836590LF103001Round diameter 25 mm x 2 mmDownload_15px
82742595LF10455480 mm x 55 mm x 1 mmDownload_15px

Defining Optical Bandpass Filters

The function of a Bandpass Filter (BP filter) is described by the center wavelength of its transmission band and the with of the band. E.g. a Bandpass Filter can be described as BP578/50, which is a filter with a center wavelength of 578 nm and a bandwith of 50 nm. Within the passband, it is typical to define the minimal or average transmission level. In modern coatings, despite several hundreds of layers, minimum transmission levels of 90% is not uncommon.

Another important aspect of a Bandpass Filter is the rejection or blocking range and level. These parameters specify in which wavelength ranges the filter must reflect as well as the permitted transmittance at these wavelengths.

Modern filters often provide OD6 or better rejection in a very wide wavelength range. However, overspecifying blocking level and range will often lead to an increase in the  number of layers in the filter causing increased production cost.

Also, deep blocking is cumbersome and slow to verify in a photo spectrometer. At Delta Optical Thin Film, we always enter into a thorough discussion with our customers to prevent unnecessary cost.

Explanations on optical filter nomenclature

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Have a look at our existing products or get in touch regarding your needs – we are the optical filter company.

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