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Understanding How A Wedge Window Can Work With Bandpass Filters

If you are trying to get some extra knowledge in terms of optics, wedging and band pass filtering are two notions you might often get to hear of. But if you make a Google search for bandpass filters or for wedge window, results may not be as clear from the very beginning. The first term for example is most often correlated with integrated circuits while the second one is presented in reverted form and takes you to a very different place…

In order to eliminate any potential confusion, we should state from the very beginning that the filters you are interested are considered optical filters. While their functioning principle is relatively the same, they filter quite different compounds, and we insert them in very different environments. As for the wedging process, it can be applied to anything from lenses to glasses and the result would be a change of the refractive processes.

If you are still confused about these two, we should try to look into their definitions. The bandpass filter is a subtype of optical filter. Optical filters are defined as devices capable to select various wavelengths and transmit their light by filtering it from other wavelengths outside of the specified frame. Filters can be either absorptive, which is the simplest type, or dichroic, a much more complex notion we are not getting into. Moreover, they can be made from plastic or plane glass, going through a process of dyeing or adding some interference coatings.

To be more specific, optical filters are classified as long pass filters, short pass filters, band pass filters and neutral density filters. The ones we are now interested into are the bandpass filters, which transmit, by definition, wavelengths of a narrow range around a given value. Otherwise said, we get to specify the bandwidth of the filter upon our needs and interests. For example, a standard bandpass filter set at 630 nm can filter the rays in between 620 and 640 nm wavelength. A red light fascicle entering such a filter will go out of it as a white light fascicle! Isn’t it fascinating?

Now back to our wedge window, wedges are another type of optical elements characterized through two plain, angled surfaces. Their main applications regard beam displacement, steering and prevention of stray-back reflections. Manufacturers provide them in an impressive range of sizes, shapes, optical glasses, with UV grade Fused Silica providing extra durability together with enhanced transmission and thermal properties.

Beam steering is about the control of a radiation pattern. While it also has applications in radio systems and acoustics, when it comes to optical systems, the effect can be achieved in two different ways: by modifying the refractive index of the transmission medium; or by resorting to a wide range of optical elements – glasses, lenses, mirrors, prisms or diffraction gratings. Wedging can be applied to all these, hence the correlation between filtering wavelengths and changing the direction of the light is more than obvious. Now you must be capable to name at least a few practical applications of the entire above. We give you a hint by starting with fluorescence microscopy…

Bandpass filters and wedge window applications are just a few of the things we can provide you in terms of optical services! Take a look in here for more information.