Polarization system

Patent metadata

Field	Value
Publication number	US-10139539-B2
Application number	US-201415102001-A
Country	US
Kind code	B2
Filing date	Dec 4, 2014
Priority date	Dec 5, 2013
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A polarization system having a first substrate with a first layer system, and at least one second substrate with a second layer system disposed downstream in a beam path from the first substrate formed by a beam source. The first and second layer systems have a first stack on the substrate and a second stack on the first stack; wherein the first stack comprises an alternating sequence of high and low refractive index oxidic layers; the second stack having an alternating sequence of high and low refractive index fluoridic layers. The first layer system splits an unpolarized beam and the second layer system splits the beam again such that the proportion of a polarized beam downstream of the second layer system is greater than that downstream of the first layer system.

First claim

What is claimed is:

1. A polarization system comprising:
a first substrate composed of a first substrate material with a first layer system disposed on the first substrate; and
at least one second substrate disposed downstream from the first substrate in a beam path formed by a beam source, the at least one second substrate being composed of a second substrate material with a second layer system disposed on the second substrate material,
wherein the first layer system comprises a first stack disposed on the first substrate and a second stack disposed directly on the first stack,
wherein the second layer system comprises a third stack disposed on the second substrate and a fourth stack disposed directly on the third stack,
wherein the first stack and the third stack comprise an alternating sequence of high and low refractive index oxidic layers,
wherein the second stack and the fourth stack comprise an alternating sequence of high and low refractive index fluoridic layers,
wherein the first layer system splits an unpolarized beam, directing a first beam portion of the unpolarized beam on the beam path, the unpolarized beam impinging on the first layer system at an angle Φ that is greater than the Brewster angle of the first substrate material,
wherein the unpolarized beam is split into a second beam portion having a first polarized component propagating through the first substrate, and the first beam portion having at least one second polarized component, which is reflected from the first layer system,
wherein the first layer system is provided with a number of oxidic and fluoridic layers such that the second polarized component is at least 90% of the first beam portion,
wherein the second layer system splits the first beam portion into a third beam portion having the first polarized component, which is transmitted through the second substrate, and a fourth beam portion having the at least one second polarized component reflected by the second layer system, and
wherein the second polarized component has a greater proportion of the fourth beam portion downstream of the second layer system than the second polarized component has in the first beam portion downstream of the first layer system,
wherein the first substrate material is calcium fluoride, and
wherein the second substrate material is quartz glass.

2. The polarization system as claimed in claim 1 , wherein the second polarized component is at least 95% of the first beam portion.

3. The polarization system as claimed in claim 1 , wherein the first beam portion impinges on the second layer system at an angle greater than the Brewster angle for the second substrate material.

4. The polarization system as claimed in claim 1 , wherein a third substrate composed of a third substrate material and a fourth substrate composed of a fourth substrate material with respective third and fourth layer systems are disposed downstream of the first and second substrates, wherein the third and fourth layer systems comprise a bottom stack applied to the third and fourth substrate respectively and a top stack applied to the bottom stack,
wherein each bottom stack comprises an alternating sequence of high and low refractive index oxidic layers and each top stack comprises an alternating sequence of high and low refractive index fluoridic layers.

5. The polarization system as claimed in claim 1 , wherein the first and second substrates are arranged such that the unpolarized beam is parallel to an outgoing beam path.

6. The polarization system as claimed in claim 1 , wherein the high and low oxidic layers used are high refractive index aluminum oxide and low refractive index silicon oxide.

7. The polarization system as claimed in claim 1 , wherein the high and low fluoridic layers used are high refractive index lanthanum fluoride, gadolinium fluoride or neodymium fluoride and low refractive index magnesium fluoride, aluminum fluoride, cryolite or chiolite.

8. The polarization system as claimed in claim 1 , wherein a sum of the number of oxidic and fluoridic layers of the first stack and second stack is greater than 40.

9. The polarization system as claimed in claim 1 , wherein the polarization system is designed for wavelength ranges between 170 and 230 nm.

10. A polarization system, comprising:
a first substrate having a first stack disposed on the first substrate and a second stack disposed directly on the first stack, the first stack and the second stack forming a first layer system;
a second substrate having a third stack disposed on the second substrate and a fourth stack disposed directly on the third stack, the third stack and the fourth stack forming a second layer system; and
a light source providing a light beam impinging on the first layer system, the light beam including a first polarized type and a second polarized type,
wherein the first stack and the third stack comprise an alternating sequence of high and low refractive index oxidic layers,
wherein the second stack and the fourth stack comprise an alternating sequence of high and low refractive index fluoridic layers,
wherein the first layer system splitting the light beam into a first reflected beam composed of the first polarized type and a first transmitted beam composed of the second polarized type, the first transmitted beam propagating through the first substrate,
wherein the first reflected beam impinges on the second layer system, the second layer system splitting the first reflected beam into a second reflected beam and a second transmitted beam, the second transmitted beam propagating through the second substrate,
wherein the second reflected beam is composed substantially of the first polarized type,
wherein the first polarized type is present in a greater proportion in the second reflected beam downstream of the second layer system than in the first reflected beam downstream of the first layer system,
wherein the first substrate material is calcium fluoride, and
wherein the second substrate material is quartz glass.

Assignees

• Jenoptik Optical Sys Gmbh

Inventors

• Bernitzki Helmut
• Klaus Michael
• Laux Sven
• Schuhmann Uwe

Classifications

• G02B27/283

  used for beam splitting or combining · CPC title

• G02B5/3066

  involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle · CPC title

• G02B1/08

  made of polarising materials · CPC title

• G02B5/3075 Primary

  for use in the UV (G02B5/3066 takes precedence) · CPC title

• G02B5/3041

  comprising multiple thin layers, e.g. multilayer stacks · CPC title