Wide-band multilayer interference filter

• US 3,914,023 A
• Filed: 12/05/1973
• Issued: 10/21/1975
• Est. Priority Date: 12/08/1972
• Status: Expired due to Term

• Current Assignee: Alfred Thelen
• Original Assignee: Alfred Thelen
• Inventors: Thelen, Alfred
• Primary Examiner(s): Strecker, Gerhard R.
• Application Number:
  US05/421,797
• Time in Patent Office: 685 Days
• Field of Search: 350/1,164,166 117/33.3
• US Class Current: 359/588
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: C09K 2323/033 Silicon compound, e.g. glass or organosilicon
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361

Abstract

A wide-band multilayer interference filter comprises a filter having a periodic arrangement of layers of the structure ABCDDCBA, where A,B,C,D indicate individual layers having each an optical thickness of one-fourth of the predetermined constructional wavelength and the mutually different refraction indices of said layers fulfill the following conditions:

Claims

1. A wide-band multilayer interference filter in which the stopbands of higher order are partly suppressed, comprising a filter having a periodic arrangement of layers of the structure ABCDDCBA, where A,B,C,D indicate individual layers having each an optical thickness of one-fourth of the predetermined constructional wavelength and the mutually different refraction indices of said layers fulfill the following conditions:

y2 - 2y. x2 - x + 1/x + 1 0 where x nA/nB y nB/nC and nA nD nB nC

2. A wide-band multilayer interference filter according to claim 1, wherein the stRuctural sequence ABCDDCBA in the layer system recurrs at least three times.

3. A wide-band multilayer interference filter according to claim 1, wherein the refractive indices of the layers are:

nA 1.46 nB 1.68 nC 2.04 nD 2.35

4. A wide-band multilayer interference filter according to claim 1, wherein the refractive indices of the layers are:

nA 1.38 nB 1.55 nC 1.83 nD 2.05

5. A wide-band multilayer interference filter according to claim 1, wherein the refractive indices of the layers are:

nA 1.80 nB 2.31 nC 3.28 nD 4.20.

6. A wide-band multilayer interference filter according to claim 1, wherein the layers A are made of SiO2, the layers B are made of Al2O3, the layers C are made of ZrO2, the layers D are made of TiO2.

7. A wide-band multilayer interference filter according to claim 1, wherein the layers A are made of MgF2, the layers B are made of ThF4, the layers C are made of La2O3, the layers D are made of ZrO2.

8. A wide-band multilayer interference filter according to claim 1, wherein the layers A are made of SiO2, the layers B are made of ZnS, the layers C are made of Si, and the layers D are made of Ge.