CN101458352A - Wide cut-off medium wave infrared filter with spectral region from 2.67mum to 2.83mum - Google Patents

Abstract

The invention relates to a wide rejection band medium wave infrared filter with the spectrum range from 2.67mum to 2.83mum, belonging to the field of surface technology. The film system of the filter is shown in the figure; wherein lambada0 is the center wavelength, lambada0 is equal to 2.17mum, alpha and beta respectively represent the center wavelength of every film system and the multiple of lambada0, alpha is equal to 1.2 and beta is equal to 1.55; Al2O3 is the substrate with the thickness from 0.2 to 10mm and the surface parallism equal to or less than 1%; H is the material Ge with high refractive index and L is the material ZnS with low refractive index. The infrared bandpass filter of the invention has a wider deep rejection band and can improve the signal-noise ratio and the imaging quality of optical remote sensing systems.

Description

A kind of spectral range is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m

Technical field

The present invention relates to a kind of spectral range is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m, belongs to the sufacing field.

Background technology

Infrared band pass filter widespread use in space optical remote system infrared camera and multi-spectral imager is mainly used in imaging observation and spectral analysis monitoring over the ground; In the new wave band/spectral coverage of China, the technical development plan of new principle space optical remote sensor, also the research and development demand has been proposed the infrared optical thin film device.

Space optical remote system infrared band pass filter requires average transmittance height in the passband, inhibition zone is dark by the degree of depth, ripple coefficient is little, transient characteristic good, can adapt to space and ground environment condition, has high stability and high reliability.

Because importance and the specific (special) requirements that use in the infrared band pass filter space, and its film structure and process for plating complexity are the emphasis of infrared optical thin film research always.

Summary of the invention

The object of the present invention is to provide a kind of spectral range is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m, improves the image quality of remote optical sensing system.

Purpose of the present invention can realize by following technical measures:

A kind of spectral range of the present invention is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m, and its complete film architecture is:

${\mathrm{\λ}}_0{\left(\frac{L}{2}H\frac{L}{2}\right)}^7\mathrm{\α}{\left(\frac{L}{2}H\frac{L}{2}\right)}^{7}L\left|{\mathrm{Al}}_2{O}_3\right|\mathrm{\β}{\left(\frac{H}{2}L\frac{H}{2}\right)}^9$

Wherein, λ ₀Be centre wavelength, λ ₀=2.17 μ m, α and β represent that respectively each film is centre wavelength and λ ₀Multiple, α=1.2, β=1.55, Al ₂O ₃Be substrate, thickness is 0.2～10mm, and the surperficial depth of parallelism≤1%, H are high-index material Ge, and L is low-index material ZnS.

Its preparation method is as follows:

(1) clean vacuum chamber: remove the rete that comes off in the vacuum chamber with suction cleaner, dip in absolute ethyl alcohol wiped clean vacuum chamber inwall with absorbent gauze then;

(2) make plating germanium evaporation boat, adopt tantalum boat pad graphite paper, after completing, be installed in the vacuum chamber.

(3) substrate that chemical cleaning is the clean vacuum chamber of packing into is evacuated to and is better than 2.0 * 10 ^-3Pa;

(4) substrate is heated to 130 ℃～175 ℃, and keeps more than the 90min;

(5) clean substrate 10～20min with ion beam, utilize the thermal resistance evaporation method of ion beam-assisted, press film system design layer by layer deposition film, wherein the rate of sedimentation of Ge is 1～2nm/s, the rate of sedimentation of ZnS is 4～5nm/s, and ion gun adopts argon gas as working gas, gas flow 30～40sccm;

(6) substrate cooling: after thin film deposition is finished, allow substrate naturally cool to room temperature.

The present invention's beneficial effect compared with prior art is:

Infrared bandpass of the present invention has the degree of depth rejection zone of broad, and the noise of raising remote optical sensing system is image quality when.

Embodiment

A kind of spectral range of the present invention is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m, and its complete film architecture is:

${\mathrm{\λ}}_0{\left(\frac{L}{2}H\frac{L}{2}\right)}^7\mathrm{\α}{\left(\frac{L}{2}H\frac{L}{2}\right)}^{7}L\left|{\mathrm{Al}}_2{O}_3\right|\mathrm{\β}{\left(\frac{H}{2}L\frac{H}{2}\right)}^9$

Wherein, λ ₀Be centre wavelength, λ ₀=2.17 μ m, α and β represent that respectively each film is centre wavelength and λ ₀Multiple, α=1.2, β=1.55, Al ₂O ₃Be substrate, thickness is 10mm, and the surperficial depth of parallelism≤1%, H are high-index material Ge, and L is low-index material ZnS.

Manufacturing process is as follows:

(1) clean vacuum chamber: remove the rete that comes off in the vacuum chamber with suction cleaner, dip in absolute ethyl alcohol wiped clean vacuum chamber inwall with absorbent gauze then;

(2) make plating germanium evaporation boat, adopt tantalum boat pad graphite paper, after completing, be installed in the vacuum chamber;

(3) substrate that chemical cleaning is the clean vacuum chamber of packing into is evacuated to 2.0 * 10 ^-5Pa;

(4) substrate is heated to 150 ℃, and keeps 90min;

(5) clean substrate 15min with ion beam, utilize the thermal resistance evaporation method of ion beam-assisted, press film system design layer by layer deposition film, wherein the rate of sedimentation of Ge is 1.5nm/s, the rate of sedimentation of ZnS is 4.5nm/s, and ion gun adopts argon gas as working gas, gas flow 30sccm;

(6) substrate cooling: after thin film deposition is finished, allow substrate naturally cool to room temperature.

Claims (2)

1, a kind of spectral range is the wide by the medium wave infrared fileter of 2.67 μ m～2.83 μ m, it is characterized in that film structure is:

${\mathrm{\λ}}_0{\left(\frac{L}{2}H\frac{L}{2}\right)}^7\mathrm{\α}{\left(\frac{L}{2}H\frac{L}{2}\right)}^{7}L\left|{\mathrm{Al}}_2{O}_3\right|\mathrm{\β}{\left(\frac{H}{2}L\frac{H}{2}\right)}^9$

Wherein, λ ₀Be centre wavelength, λ ₀=2.17 μ m, α and β represent that respectively each film is centre wavelength and λ ₀Multiple, α=1.2, β=1.55, Al ₂O ₃Be substrate, H is high-index material Ge, and L is low-index material ZnS.

2, a kind of spectral range as claimed in claim 1 is the wide by the LONG WAVE INFRARED narrow band pass filter of 2.67 μ m～2.83 μ m, it is characterized in that: substrate Al ₂O ₃Thickness is 0.2～10mm, the surperficial depth of parallelism≤1%.