Narrowband transmission filter and on-chip spectral analysis and imaging system

Abstract

The invention discloses a narrow-band transmission filter and an on-chip spectral analysis and imaging system. The filter includes a substrate. A grating structure is first formed on the surface of the substrate, and then a metal / metal-like film is deposited, or a metal / metal-like film is deposited on the surface of the substrate first. , and then form a grating structure, and adjust the band-pass center wavelength by changing the base material, metal / metal-like material and grating structure; the system includes a filter array and a detector array, and the filter array is composed of a plurality of different band-pass center wavelengths The filter unit is formed, and each filter unit adopts the above-mentioned narrow-band transmission filter, and the filter units of the filter array and the detector units of the detector array are combined one by one. The filter of the present invention has a large working wavelength bandwidth and a narrow passband, and filters with different central wavelengths can be obtained through one-time graphic processing. By forming an on-chip spectral analysis and imaging system with a detector array, the system performance is greatly improved, and Reduced system complexity.

Description

Technical field [0001] The present invention relates to a narrowband transmission filter and a preparation method thereof, on-chip spectral analysis and imaging system, belongs to the field of spectral analysis and imaging. Background [0002] A filter is a device that selects a specific wavelength of light in a wide spectrum of incident light separately in transmitted or reflected light. A band-pass filter is a filter that allows only specific wavelengths of light to pass through, and its main performance indicators are wavelength selectivity and operating wavelength range. Wavelength selectivity is reflected in the fact that the band-pass wavelength range can be very narrow, and the transmittance of light in the band-pass wavelength range is as high as possible higher than the transmittance of light in the non-band-pass wavelength range. The operating wavelength range refers to the low-transmitted non-band-pass wavelength range, and the wider the better. Bandpass filtering is g...

AI Technical Summary

Problems solved by technology

Optics Express, Volume 18, page 14056, reported a metal nanohole array structure bandpass filter, which achieves filtering through the anomalous transmission effect caused by surface plasmon resonance, and can achieve different bandpass wavelengths by simply changing the in-plane structure , which greatly simplifies the processing technology of different band-pass center wavelength filter arrays, but the center wavelength transmittance is only 30% low, and the band-pass wavelength range is greater than 20% of the center wavelength, it is difficult to achieve high-precision wavelength selection, and cannot meet The Need for High-Resolution Spectral Analysis

Optics Express, Volume 20, page 21917, reports a metal mirror resonant cavity bandpass filter. The effective refractive index of the medium layer can be adjusted by preparing hole structures with different filling ratios in the medium layer, so that it can be processed by a single photolithography process. The process prepares filters with different bandpass center wavelengths, but the adjustable range of the center wavelength is limited, and there is an inherent disadvantage of low transmittance of the metal mirror resonator filter, which is difficult to meet the actual needs

Optics Letters, Volume 40, page 5062, reports a bandpass filter with a dielectric grating waveguide structure. The bandpass center wavelength can be adjusted by changing the size of the grating and waveguide, showing high transmittance and a narrow bandpass wavelength range. But the working wavelength range is limited, less than one-fifth of the band-pass center wavelength

Optics Letters, Volume 41, page 1913, reported a metal grating waveguide bandpass filter and its on-chip spectrum application. The bandpass center wavelength can be adjusted by changing the size of the grating and waveguide, showing high transmittance and Narrow band-pass wavelength range, but the free spectral width, that is, the wavelength distance between the two transmission peaks is small, resulting in a limited working wavelength range, which is less than one-seventh of the band-pass center wavelength

[0005] It can be seen that although the existing technologies represented by the above examples all exhibit bandpass filters, their wavelength selectivity and spectral resolution are limited, and their operating wavelength range is narrow, so it is difficult to meet the technical requirements of on-chip spectral analysis and imaging applications.

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