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.

Fluorescencebandpassfilters

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.

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.

Bandpass Filterthorlabs

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.

A simple refracting telescope may be constructed from a pair of convex lenses, where the larger of the two lenses is the objective. This lens produces a real image at the focal plane that is viewed with an eyepiece. The eyepiece is placed so that its focal plane coincides with the focal plane of the objective, resulting in a virtual image at ‘infinity’. Parallel light rays from a distant source cross at the focal point of the objective lens. The eyepiece is placed such that its focal plane coincides with the focal plane of the objective lens.

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.

Bandpass filter

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.

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

Notchfilter

Optical filter

The aperture of the objective, Do, is used to calculate the field of view, the resolving power and the magnification of the telescope.

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.

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.

Study Astronomy Online at Swinburne University All material is © Swinburne University of Technology except where indicated.

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.

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.