BandpassFilter thorlabs

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.

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.

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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.

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.

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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.

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.

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.

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.

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Optical Bandpassfilter

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.

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.

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