Linear gradient filters are so-called "linear" because their spectral characteristics are different at different positions and change linearly with the change of spatial position. Linear gradient filters have the advantages of wavelength gradient, channel selection, stable performance, etc. The spectral characteristics change linearly due to the use of ion-assisted or ion-beam sputtering processes such as the formation of a wedge-shaped film layer by plating a multilayer film system with varying thicknesses on the surface of the substrate.
Compared with traditional narrow-band filters, linear gradient filters have near-continuous spectral channels, so the use of linear gradient filters for spectroscopy can obtain a high spectral resolution. Compared with prism and grating type spectral imagers, spectral imagers based on linear gradient filters are characterized by high integration, high stability and high resolution, etc., with compact structure, small volume and light weight, as well as low R & D and manufacturing costs, which have good application prospects. Linear gradient filters can also be used in portable spectrometers, grating secondary optical separation / up to the design of laser mirrors and other aspects and fields.
Linear Variable Filter (LVF) is a new type of spectral element developed after prisms, gratings, and a variety of recently developed spectral elements, which has the advantages of small size, multiple passbands, and arbitrarily designed passband positions compared to prisms, gratings, and other traditional spectral elements. As the linear gradient filter can be combined with CCD/CMOS detector array to form a spectral detector, greatly simplifying the spectral system, improve the reliability, stability and optical efficiency of the instrument, by more and more attention. Spectrometers with linear gradient filters as the core spectroscopic elements have been successfully applied to many fields such as aerospace, field exploration, atmospheric monitoring, food safety monitoring, biofluid analysis and multi/hyper/hyperspectral imaging.
Linear gradient filter physical picture
Applications:
spectral imaging technique
Compared with prism and grating type and other spectral imagers, spectral imagers based on linear gradient filters are characterized by high integration, high stability and high resolution, etc. The whole machine has a compact structure, small size and light weight, as well as low research and development and manufacturing costs, which has a good application prospect.
Linear graduated filters can also be used in portable spectrometers, grating secondary light separation/cutoff, laser reflector design and other aspects and fields.