A short-wave infrared narrow-band filter and its preparation method

Abstract

The invention discloses a short-wave infrared narrowband optical filter. The short-wave infrared narrowband optical filter is characterized in that the short-wave infrared narrowband optical filter comprises a substrate and a front film system and a reverse film system formed at surfaces of the substrate at two sides, the front film system is A / (HL)<4>L(HL)<8>L(HL)<8>L(HL)<4>1.64H0.64L / S, the reverse film system is A / (0.5HL0.5H)<11>[alpha](0.5HL0.5H)<12>[beta](0.5LH0.5L)<7>[gamma](0.5LH0.5L)<10>[omega](0.5LH0.5L)<10> / S, and in the film systems, A refers to air, S refers to an H-K9L glass substrate, H refers to a high-refractive-index material titanium pentoxide, L refers to a low-refractive-index material silicon dioxide, and alpha, beta, gamma, and omega respectively refer to multiples of the central wavelengths of the film systems to the central wavelength. According to the optical filter, the infrared narrowband optical filter transmission spectrum with the central wavelength of 1240 nm is provided, the rise and the decline of a transmission band are less than 0.5% along the steepness, the passband average transmittance reaches 80%, the stop-band average transmittance is less than 0.5%, the spectrum range is limited, the background interference is suppressed, and the target resolution is improved.

Description

Technical field [0001] The invention belongs to the technical field of optical element design, and relates to a 1240nm shortwave infrared narrowband filter that can meet the use of 80K low temperature environment and a preparation method thereof. Background technique [0002] Short-wave infrared narrow-band filters have broad application prospects in optical analysis instruments and optical detectors. They are mainly used for ground imaging observation and spectral analysis monitoring. my country’s high-resolution ground observation system is a major project for short-wave narrowband filters. The optical film put forward research and development needs. [0003] The short-wave infrared narrow-band filter for large-field infrared multi-spectral scanners requires high pass-band average transmittance, deep suppression band cut-off depth, small pass-band ripple coefficient, and wide cut-off range. It is suitable for 80K low temperature and ground environmental conditions , With high rel...

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Problems solved by technology

[0004] Since the short-wave infrared narrow-band filter is packaged in front of the detector and used in a special working environment, it needs to meet the instantaneous temperature impact from the low temperature limit of 80K to the high temperature limit of 80°C. The center wavelength drift of the filter and the phenomenon of film layer shedding, the low-temperature short-wave infrared narrow-band filter has always been the focus of optical thin film research

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