CN-113495313-B - Optical filter and spectrometer comprising an optical filter

Abstract

An optical filter and a spectrometer including the optical filter are provided. The optical filter includes at least one first filter element having a first center wavelength of a first band and at least one second filter element disposed on the same plane as the at least one first filter element, the at least one second filter element having a second center wavelength of a second band. The at least one first filter element includes a first bandpass filter including a plurality of first Bragg reflection layers and at least one first cavity disposed between the plurality of first Bragg reflection layers, and a first multilayer disposed on the first bandpass filter, the first multilayer having a center wavelength different from a first center wavelength of the first Bragg reflection layers to block light of other wavelength bands than the first wavelength band.

Inventors

• JIN XIAOZHE
• LU YONGJIN
• PU YANXIANG
• Li Zaichong

Assignees

• 三星电子株式会社

Dates

Publication Date

20260512

Application Date

20201224

Priority Date

20200408

Claims (20)

1. 1. An optical filter, comprising: at least one first filter element, and At least one second filter element arranged on the same plane as the at least one first filter element, Wherein each of the at least one first filter element comprises: A first bandpass filter having a first center wavelength within a first wavelength band and including a plurality of first Bragg reflection layers and at least one first cavity disposed between the plurality of first Bragg reflection layers, an A first multilayer disposed on the first band-pass filter, the first multilayer having a center wavelength different from a first center wavelength of the first band-pass filter to block light of a wavelength other than the first band, Wherein each of the at least one second filter element comprises: a second bandpass filter having a second center wavelength within a second wavelength band and including a plurality of second Bragg reflection layers and at least one second cavity disposed between the plurality of second Bragg reflection layers, and And a second multilayer disposed below the second band pass filter, a center wavelength of the second multilayer being different from a second center wavelength of the second band pass filter to block light of other bands than the second band.
2. 2. The optical filter according to claim 1, wherein each of the plurality of first bragg reflection layers and the first multilayer has a structure in which a plurality of material layers having refractive indices different from each other are alternately stacked, Wherein each material layer of the plurality of material layers in the first plurality of layers has a first thickness and is made of a first material, and Wherein at least one of the first thickness or the first material is different from a second thickness or a second material of each of the plurality of material layers of the plurality of first bragg reflector layers.
3. 3. The optical filter of claim 2, wherein the first plurality of layers comprises a third bragg reflector layer comprising layers of material having the same optical thickness.
4. 4. The optical filter of claim 2, wherein the first plurality of layers comprises a first pass filter comprising layers of material, at least some of the layers of material having different optical thicknesses.
5. 5. The optical filter of claim 4, wherein the first pass filter comprises a short-wave pass filter.
6. 6. The optical filter of claim 2, wherein the first center wavelength of the first band-pass filter is adjusted by changing a thickness or an effective refractive index of the at least one first cavity.
7. 7. The optical filter according to claim 1, wherein each of the plurality of second bragg reflection layers and the second multilayer has a structure in which a plurality of material layers having refractive indices different from each other are alternately stacked, Wherein the plurality of material layers in the second plurality of layers have a third thickness and are made of a third material, and Wherein at least one of the third thickness or the third material is different from a fourth thickness or a fourth material of each of the plurality of material layers of the plurality of second bragg reflector layers.
8. 8. The optical filter of claim 7, wherein the material layer in each of the plurality of second bragg reflector layers is the same as the material layer in the first plurality of layers and the material layer in the second plurality of layers is the same as the material layer in each of the plurality of first bragg reflector layers.
9. 9. The optical filter of claim 7, wherein the second plurality of layers comprises a fourth bragg reflector layer comprising material layers having the same optical thickness.
10. 10. The optical filter of claim 7, wherein the second plurality of layers comprises a second pass filter comprising layers of material, at least some of the layers of material having different optical thicknesses.
11. 11. The optical filter of claim 10, wherein the second pass filter comprises a long-pass filter.
12. 12. The optical filter of claim 1, wherein the second center wavelength of the second bandpass filter is adjusted by changing the thickness or effective refractive index of the second chamber.
13. 13. The optical filter of claim 1, wherein the plurality of second bragg reflector layers comprise a material that absorbs light of the first wavelength band.
14. 14. The optical filter of claim 1, further comprising at least one third filter element disposed on the same plane as the at least one first filter element and the at least one second filter element, wherein the at least one third filter element has a third center wavelength between the first band and the second band.
15. 15. The optical filter of claim 1, further comprising an additional filter disposed on the at least one first filter element and the at least one second filter element to transmit only a specific wavelength band.
16. 16. The optical filter of claim 15, wherein the additional filter comprises a color filter or a broadband filter.
17. 17. The optical filter of claim 1, wherein short wavelength absorption filters are provided on some of the at least one first filter element and the at least one second filter element and long wavelength blocking filters are provided on other of the at least one first filter element and the at least one second filter element.
18. 18. A spectrometer, comprising: Optical filter, and A sensing device receiving light transmitted through the optical filter; Wherein the optical filter comprises at least one first filter element and at least one second filter element arranged on the same plane as the at least one first filter element, Wherein each of the at least one first filter element comprises a first bandpass filter having a first center wavelength within a first wavelength band and comprising a plurality of first Bragg reflection layers and at least one first cavity disposed between the plurality of first Bragg reflection layers, and a first multilayer disposed on the first bandpass filter, the first multilayer having a center wavelength different from the first center wavelength of the first bandpass filter to block light of other wavelength bands than the first wavelength band, Wherein each of the at least one second filter element includes a second bandpass filter having a second center wavelength within a second wavelength band and including a plurality of second Bragg reflection layers and at least one second cavity disposed between the plurality of second Bragg reflection layers, and a second multilayer disposed below the second bandpass filter, the second multilayer having a center wavelength different from the second center wavelength of the second bandpass filter to block light of other wavelength bands than the second wavelength band.
19. 19. The spectrometer of claim 18, wherein each of the plurality of first bragg reflecting layers and the first plurality of layers has a structure in which a plurality of material layers having refractive indices different from each other are alternately stacked, Wherein each material layer of the plurality of material layers in the first plurality of layers has a first thickness and is made of a first material, and Wherein at least one of the first thickness or the first material is different from a second thickness or a second material of each of the plurality of material layers of the plurality of first bragg reflector layers.
20. 20. The spectrometer of claim 19, wherein the first multilayer comprises a third bragg reflective layer comprising material layers having the same optical thickness.

Description

Optical filter and spectrometer comprising an optical filter Cross Reference to Related Applications The present application is based on and claims priority of korean patent application No.10-2020-0042970 filed on 8 th month 4 in 2020 and korean patent application No.10-2020-0078814 filed on 26 th month 6 in 2020, which are incorporated herein by reference in their entireties. Technical Field The present disclosure relates to optical filters and spectrometers including optical filters. Background Spectrometers are one of the important optics in the optical field. However, since the spectrometer according to the related art includes various optical devices, the spectrometer is bulky and heavy. Recently, there is a demand for downsizing of spectrometers, and thus, research has been conducted to realize integrated circuits and optical devices simultaneously on a semiconductor chip. Disclosure of Invention An optical filter and a spectrometer including the optical filter are provided. Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments presented herein. According to an aspect of the present disclosure, there is provided an optical filter including at least one first filter element having a first center wavelength within a first wavelength band, and at least one second filter element disposed on the same plane as the at least one first filter element, the at least one second filter element having a second center wavelength within a second wavelength band, wherein each of the at least one first filter element includes a first bandpass filter including a plurality of first Bragg reflection layers and at least one first cavity disposed between the plurality of first Bragg reflection layers, and a first multilayer disposed on the first bandpass filter, the first multilayer having a center wavelength different from the first center wavelength of the plurality of first Bragg reflection layers to block light of other wavelength bands than the first wavelength band. Each of the plurality of first bragg reflection layers and the first plurality of layers may have a structure in which a plurality of material layers having refractive indexes different from each other are alternately stacked, wherein each of the plurality of material layers in the first plurality of layers has a first thickness and is made of a first material, and wherein at least one of the first thickness or the first material is different from a second thickness or a second material of each of the plurality of material layers of the plurality of first bragg reflection layers. The first multilayer may include a third bragg reflective layer including material layers having the same optical thickness. The first multilayer may include a first pass filter including layers of material, at least some of which have different optical thicknesses. The first pass filter may comprise a short wave pass filter. The first center wavelength of the first band-pass filter may be adjusted by varying the thickness or effective refractive index of the at least one first cavity. The at least one second filter element may include a second bandpass filter including a plurality of second Bragg reflection layers and a second cavity between the plurality of second Bragg reflection layers, and a second multilayer disposed on the second bandpass filter, the second multilayer having a center wavelength different from a second center wavelength of the plurality of second Bragg reflection layers to block light of other wavelength bands than the second wavelength band. Each of the plurality of second bragg reflection layers and the second plurality of layers may have a structure in which a plurality of material layers having refractive indexes different from each other are alternately stacked, wherein the plurality of material layers in the second plurality of layers may have a third thickness and be made of a third material, and wherein at least one of the third thickness or the third material may be different from a fourth thickness or a fourth material of each of the plurality of material layers of the plurality of second bragg reflection layers. The material layer in each of the plurality of second bragg reflective layers may be the same as the material layer in the first plurality of layers, and the material layer in the second plurality of layers may be the same as the material layer in each of the plurality of first bragg reflective layers. The second plurality of layers may include a fourth bragg reflective layer including material layers having the same optical thickness. The second multilayer may include a second pass filter including layers of material, at least some of which have different optical thicknesses. The second pass filter may comprise a long-pass filter. The second center wavelength of the second band pass filter may be adjusted by changin