Laser-operated light source

Patent metadata

Field	Value
Publication number	US-10078167-B2
Application number	US-201414490966-A
Country	US
Kind code	B2
Filing date	Sep 19, 2014
Priority date	Sep 20, 2013
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A laser-operated light source encompasses a chamber for accommodating an ionizable gas and an ignition source for ionizing the gas in the chamber for generating a plasma. The light source furthermore encompasses a laser for inputting laser energy into the plasma such that, under the impact of the laser radiation, the plasma emits useful light, which forms the output signal of the light source, wherein provision is made for means for coupling the useful light into a transferring optical fiber. In the case of the light source according to the invention, at least one mode scrambler is assigned to the optical fiber or the optical fibers.

First claim

What is claimed is:

1. A light source, comprising:
a chamber configured to accommodate an ionizable gas;
an ignition source configured to ionize the gas in order to generate a plasma;
a laser configured to input laser energy into the plasma such that, under impact of the laser energy, the plasma emits light that forms an output signal of the light source;
a fiber optical configured to couple the light into a plurality of optical fibers; and
a first mode scrambler and a second mode scrambler corresponding to at least one optical fiber of the plurality of optical fibers,
wherein the plurality of optical fibers comprises:
first and second optical fibers corresponding to the first and second mode scramblers and
a third optical fiber:
in optical communication with the first optical fiber and the second optical fiber,
comprising a larger diameter than a diameter of both of the first optical fiber and the second optical fiber; and
connected upstream of the first optical fiber and the second optical fiber,

the first, second, and third optical fibers, the first mode scrambler, and the second mode scrambler apply a surface homogeneity and an angle homogeneity to the light.

2. The light source according to claim 1 , wherein the first mode scrambler and the second mode scrambler are assigned consecutively in fiber direction.

3. The light source according to claim 2 , wherein:
the first mode scrambler impresses curvatures comprising a larger first radius of curvature onto one or more of the plurality of optical fibers, and
the second mode scrambler impresses curvatures comprising a smaller second radius of curvature onto one or more of the plurality of optical fibers.

4. The light source according to claim 2 , wherein the first mode scrambler is embodied as a winding device configured to receive at least one of the plurality of optical fibers wound around the winding device for generating alternating curvatures consecutively in fiber direction in a plurality of windings.

5. The light source according to claim 4 , wherein:
the first mode scrambler is embodied as a winding device, which impresses curvatures comprising a larger first radius of curvature onto one or more of the plurality of optical fibers, and
the second mode scrambler, which is embodied as a clamping device, is arranged downstream from said first mode scrambler and impresses curvatures comprising a smaller second radius of curvature onto one or more of the plurality of optical fibers.

6. The light source according to claim 2 , wherein the second mode scrambler is embodied as a clamping device comprising two clamping plates configured to clamp at least one of the plurality of optical fibers between the two clamping plates in a meandering course.

7. The light source according to claim 2 , wherein the first mode scrambler is arranged upstream of the second mode scrambler in propagation direction of the light.

8. The light source according to claim 1 , wherein the light is light having a wavelength between 400 nm and 950 nm.

9. The laser-operated light source of claim 1 , wherein:
the first optical fiber and the second optical fiber are configured to be guided parallel to one another, and
the first optical fiber and the second optical fiber are configured to receive the light from the fiber optical coupler with a homogeneity and intensity which is substantially identical.

10. A method comprising:
igniting an ionizable gas inside a chamber with an ignition source to generate a plasma;
inputting laser energy to the plasma such that, under the impact of the laser energy, the plasma emits light that forms an output signal of a light source;
passing the light into a plurality of optical fibers; and
passing one or more of the plurality of optical fibers through a first mode scrambler and a second mode scrambler,
wherein the plurality of optical fibers further comprises:
a first optical fiber and a second optical fiber to which the first mode scrambler and the second mode scrambler are assigned, and
a third optical fiber:
in optical communication with the first optical fiber and the second optical fiber,
comprising a larger diameter than a diameter of the first optical fiber and a diameter of the second optical fiber, and
connected upstream of the first optical fiber and the second optical fiber,

the first, second, and third optical fibers, the first mode scrambler, and the second mode scrambler apply a surface homogeneity and an angle homogeneity to the light.

Assignees

• Asml Netherlands Bv

Inventors

• Brune Ekkehard
• Frerking Dieter
• Thöniss Thomas
• Spruch Claus

Classifications

• H01S3/005

  Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B) · CPC title

• G01J3/10 Primary

  Arrangements of light sources specially adapted for spectrometry or colorimetry · CPC title

• G02B27/0994

  Fibers, light pipes (optical fibers per se G02B6/02) · CPC title

• G02B6/0006 Primary

  Coupling light into the fibre (in general G02B6/4298) · CPC title

• H01J2893/0063

  Plasma light sources · CPC title