What are the types of Optical Filters ?

Optical Filters

Optical Filters is an optical device that attenuates (absorbs) certain light bands in a light wave, or passes through a precisely selected small range of bands, while reflecting (or absorbing) other undesired bands. It is usually made by adding special dyes to a plastic or glass sheet. The original transmittance of the glass sheet and the air is almost the same, all the colored light can pass through, transparent and colorless, but dyed with dyes, the molecular structure and refractive index changes, on the different colors of light through the impact. For example, after a beam of white light passes through a blue filter, it is mainly blue light that is emitted, while most of the green and red light is absorbed.

Bandpass Filters:

Bandpass Filters are used to selectively transmit a portion of the spectrum while rejecting all other wavelengths. Fluorescence Filters, which have been designed to maximize the energy of the excitation and emission bands, typically have broad bandwidths of 20 – 70nm.

Color Glass Filters：

Due to its selective absorption in visible wavelength range, color glass filter will exhibit various color depending the glass type. Color glass filter provides an economical filter for various applications.

Neutral Filters：

ND（Neutral Density） filters include absorptive and reflective filters，which are used in attenuating lasers and other optical signals. Absorptive filters minimize back reflections, which can be reduced further by adding an antireflection coating to the filter. Reflective filters are available with either a BK7 or UV Fused Silica substrate.

Shortpass Filters：

Shortpass Filters, also known as Shortpass Edge Filters, are used to transmit wavelengths shorter than the cut-off wavelength of the filter. Shortpass Filters are typically designed for a 0° Angle of Incidence, whereas Shortpass Dichroic Filters are designed for use at a 45° Angle of Incidence. Shortpass Filters can be used with Longpass Filters to create custom bandpass filters to selectively transmit portions of the spectrum while rejecting all other wavelengths.

Longpass Filters：

Longpass Filters, also known as Longpass Edge Filters, are designed to transmit wavelengths greater than the cut-on wavelength of the filter. Longpass Filters are commonly used to isolate portions of the spectrum in a variety of industrial or life sciences applications including microscopy or fluorescence instrumentation. Longpass Filters are typically designed for a 0° Angle of Incidence, whereas Longpass Dichroic Filters are designed for using at a 45° Angle of Incidence.

Notch filters：

Notch filters are commonly called suppression filters, band-stop filters, etc. The characteristic of this filter is that it can pass most wavelengths with almost no loss, and the specified band (stop band).

When you are looking for high quality Optical Filter for your project, our company is undoubtedly your best choice. Good reputation is the testimony of our strength. Over the years, our company's optical filters have been widely used in various fields and won the praise of many customers. Our customers are all over the world, and their trust and support are the driving force for us to keep moving forward.