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Introduction of linear gradient filter

2020-02-14

Linear gradient filter (lvof) is a new type of light dividing element developed after prism, grating and many kinds of light dividing elements developed recently. Compared with prism, grating and other traditional light dividing elements, lvof has the advantages of small volume, many passbands and arbitrary design of passband position.


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Linear gradient filter


Because the linear gradient filter can be combined with CCD / CMOS detector array to form a detector of recognizable spectrum, which greatly simplifies the beam splitting system and improves the reliability, stability and optical efficiency of the instrument, more and more attention has been paid. The spectrometer with linear gradient filter as the core spectroscopic element has been successfully applied to many fields, such as aerospace, field exploration, atmospheric monitoring, food safety detection, biological fluid analysis and multi / high / hyperspectral imaging.


Between the ion beam exit window and the sample to be processed, a baffle plate with a triangular window is placed perpendicular to the direction of ion beam exit. During ion beam etching, the sample moves back and forth at a constant rate. After a certain number of etching times, the thickness difference perpendicular to the direction of sample motion is obtained, and the designed wedge-shaped interlayer is finally obtained.


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Lvof processing flow diagram


The complete process flow of the preparation of linear gradient filter is shown in the figure. First, the first coating is carried out on the K9 substrate, and the lower film system and the intermediate resonator layer are well plated; secondly, the intermediate layer is etched according to the above method to obtain a wedge-shaped resonator layer with a certain wedge angle; finally, with the second coating, the preparation of linear gradient filter can be completed.


The filter adopts K9 substrate with size of 80 mm x 10 mm. First of all, we need to finish the plating of the lower reflection film system and the middle resonator layer. In the reflective film system, we usually use the metal with large coefficient and stable optical properties as the metal film material. Aluminum is commonly used in the ultraviolet region, aluminum and silver are commonly used in the visible region, and gold, silver and copper are commonly used in the infrared region. In addition, chromium and platinum are often used as membrane materials for some special films. Because aluminum, silver, copper and other materials are easy to oxidize in the air and reduce performance, they must be protected by dielectric film. The commonly used protective film materials are SiO, Mgf2, SiO2, Al2O3, etc.


Related protective film materials of ATS:


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ATS is a professional manufacturer of vacuum coating materials. It's production of some coating materials are widely used in the production of filters, the specifications of products are complete, and can be customized according to the specific requirements of customers, welcome to inquire!