A multi-spectral dual-channel photonic crystal filter in the visible light region

Abstract

The invention discloses a multispectral dual-channel photonic crystal filter at a visible region. With the filter, the regular filtering of the previous narrow-band multi-channel filter can be broken at the filtering range. A fabry-perot photonic crystal filter and a short-wave-pass photonic crystal filter are laminated and combined to form a (A / B / B / A)<2> B' (A / B / B / A) (yC / xD / yC) <n> type photonic crystal filter, wherein the refractive index of the A is higher than B, the refractive index of the D is higher than C, the B and B' are same kind of materials with different thicknesses, the n is the number of periods of the short-wave-pass photonic crystal filter and is a positive integer, and the x and y are positive numbers. Two different filter channels can be generated simultaneously at a visible region only by changing the x and y values under the circumstances that the n is kept to be unchanged. According to the invention, the structure is simple; the processing is convenient; and the pass band width is widened. The technical scheme can be used for preparing a dual-channel filter having all light-transmitting wavebands in no linear relation; and the average transmittance is over 90%; and the brightness and color purity of the projection system can be improved effectively.

Description

technical field [0001] The invention relates to a photonic crystal filter, in particular to a multi-spectrum dual-channel photonic crystal filter in the visible light region. Background technique [0002] Photonic crystals are periodic structures composed of structural units according to certain arrangement rules. According to the different arrangement of the medium, it can be divided into one-dimensional, two-dimensional and three-dimensional photonic crystals. Photonic band gap is the most prominent feature of photonic crystals. Light with a wavelength in the forbidden band range cannot be transmitted. This feature makes photonic crystals widely used in many aspects, such as omnidirectional mirrors, photonic crystal waveguides, photonic crystal fibers, and polarizers. , filter, etc. The projection optical system has strict requirements on the light source. The purity of the color of the light source determines the quality of the color of the projection screen. In order t...

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Problems solved by technology

[0003] Chen Tao et al. (Development of multi-spectral bandpass linear gradient filter, Optoelectronic Engineering, 2007 (34), 72-75) designed a multi-channel filter for spectral filtering. This linear filter requires the center wavelength and the spatial position of the channel The relationship is linear, and the filtering requirements for each channel with a fixed position and no linear relationship cannot be met

[0004] Gu Peifu (Multi-peak interference filter for wavelength division multiplexing system, Acta Photonica Sinica, 2003, 32 (7): 837-839) experimental group made a multi-peak interference filter for wavelength division multiplexing system, but The filtering passband of this Fabry-Perot interference filter is very narrow, and the steepness of the edge of the passband is not good.

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