Optical filters transmit light particularly within a selective range of wavelengths, while the excessive light is absorbed or reflected, according to which optical filters are divided into two major classifications: reflective or absorbing type of filters. To classify in terms of wavelength, there are Shortpass or long-pass filters which only allow light with short or long wavelengths to pass, and bandpass filters which allow the light within their specified wavelength band to come through. There are various types of optical filters including : absorbing glass filters, interference filters, Fabry–Perot filters, Lyot filters, or based on other designs. The applications are manifold, ranging from photography, fluorescence microscopy, spectroscopy, clinical chemistry, or machine vision inspection. In astronomy, optical filters are used to restrict light passed to the desired spectral band.
Hangzhou Shalom EO offers a vast variety of Optical Filters of both reflective and absorbing types, consisting of Bandpass Filters, Neutral Density, Dichroic Filters, Notched Filters, Colored glass Absorptive Filters, IR Filters, and Laser line Filters.
Within the reflective-filter categories, Bandpass filters are designed to selectively transmit light over a certain wavelength band while rejecting the remaining light in a given spectrum, with a wide wavelength range of 200-1200nm for selecting; Neutral Density filters evenly attenuate transmission, reducing the intensity of light by reflecting or absorbing a portion of it; Dichroic filters only transmit the wanted portion of wavelengths while other wavelengths are destructively canceled or reflected through interference, thus are particularly suited for precise scientific work, since their exact color range can be controlled by the thickness and sequence of the coatings; Notched filters would transmit most wavelength with little intensity loss and attenuate light within a wavelength band to a very low level; While IR filters are for infrared (IR) applications, and Laser line filters are ideal for transmitting laser light with particular transmission wavelength.