Pulsed light generation device, pulsed light generation method, exposure apparatus having pulsed light generation device and inspection apparatus having pulsed light generation device

Patent metadata

Field	Value
Publication number	US-11303091-B2
Application number	US-202016733534-A
Country	US
Kind code	B2
Filing date	Jan 3, 2020
Priority date	May 26, 2016
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A pulsed light generation device, includes: a first optical fiber through which first pulsed light and second pulsed light, having an intensity that decreases while an intensity of the first pulsed light increases, and increases while the intensity of the first pulsed light decreases, having been multiplexed and entered therein, are propagated; and a second optical fiber at which the first pulsed light, having exited the first optical fiber and entered therein, is amplified while being propagated therein, wherein: at the first optical fiber, phase modulation occurs in the first pulsed light due to cross phase modulation caused by the second pulsed light; and self-phase modulation occurring in the first pulsed light at the second optical fiber is diminished by the phase modulation having occurred at the first optical fiber.

First claim

What is claimed is:

1. A light amplification device, comprising:
a first optical fiber to which first pulsed light, and second pulsed light having a peak intensity greater than a peak intensity of the first pulsed light enter; and
a second optical fiber that amplifies the first pulsed light having exited the first optical fiber, wherein
a value of multiplication of nonlinearity of the first optical fiber and a length of the first optical fiber is greater than a value of multiplication of nonlinearity of the second optical fiber and a length of the second optical fiber.

2. The light amplification device according to claim 1 , wherein:
the nonlinearity of the first optical fiber and the nonlinearity of the second optical fiber are different from each other.

3. The light amplification device according to claim 2 , wherein:
the nonlinearity of the first optical fiber is greater than the nonlinearity of the second optical fiber.

4. The light amplification device according to claim 2 , wherein:
a mode field diameter of the first optical fiber and a mode field diameter of the second optical fiber are different from each other.

5. The light amplification device according to claim 4 , wherein:
the mode field diameter of the first optical fiber is smaller than the mode field diameter of the second optical fiber.

6. The light amplification device according to claim 1 , wherein:
the length of the first optical fiber and the length of the second optical fiber are different from each other.

7. The light amplification device according to claim 6 , wherein:
the length of the first optical fiber is longer than the length of the second optical fiber.

8. The light amplification device according to claim 1 , wherein:
the second optical fiber comprises a plurality of optical fibers disposed in series.

9. The light amplification device according to claim 1 , wherein:
the first optical fiber includes silica glass; and
the second optical fiber is an Ytterbium Doped Fiber Amplifier.

10. The light amplification device according to claim 1 , wherein:
an intensity of the second pulsed light decreases while an intensity of the first pulsed light increases, and the intensity of the second pulsed light increases while the intensity of the first pulsed light decreases.

11. The light amplification device according to claim 1 , wherein:
the intensity of second pulsed light has a maximum value at time points both before and after a time point at which the intensity of the first pulsed light peaks.

12. The light amplification device according to claim 1 , further comprising:
a separation element disposed between the first optical fiber and the second optical fiber, which separates the first pulsed light and the second pulsed light from each other.

13. The light amplification device according to claim 12 , wherein:
wavelength of the first pulsed light and wavelength of the second pulsed light are different from each other; and
the separation element includes a wavelength selection filter that allows light with a wavelength of the first pulsed light to be transmitted and absorbs light with a wavelength of the second pulsed light.

14. A light generation device, comprising:
a first laser light source that emits first pulsed light;
a second laser light source that emits second pulsed light having a peak intensity greater than a peak intensity of the first pulsed light and also having wavelength different from wavelength of the first pulsed light;
a multiplexer element that multiplexes the first pulsed light having exited the first laser light source and the second pulsed light having exited the second laser light source;
the light amplification device according to claim 13 to which the first pulsed light and the second pulsed light, having exited the multiplexer element enter; and
a wavelength conversion unit that converts a wavelength of the first pulsed light having exited the second optical fiber and entered therein.

15. The light amplification device according to claim 12 , wherein:
polarization direction of the first pulsed light and polarization direction of the second pulsed light are different from each other; and
the separation element includes a polarization beam splitter that changes a propagation direction of the first pulsed light or a propagation direction of the second pulsed light so that the second pulsed light propagates in a direction other than a direction toward an entering end of the second optical fiber.

16. A light generation device, comprising:
a third laser light source that emits third pulsed light:
a demultiplexer element that branches the third pulsed light into pulsed light to be propagated through a first optical path and pulsed light to be propagated through a second optical path;
a first modulation element that is disposed in the first optical path;
a second modulation element that is disposed in the second optical path;
a third optical fiber that is disposed in the second optical path, wherein
the first modulation element modulates the pulsed light to be propagated through the first optical path to generate first pulsed light,
the second modulation element and the third optical fiber respectively modulates and amplifies the pulsed light to be propagated through the second optical path to generate second pulsed light having a peak intensity greater than a peak intensity of the first pulsed light, and
the first modulation element modulates the pulsed light to be propagated through the first optical path and/or the second modulation element modulates the pulsed light to be propagated through the second optical path, so that the polarization direction of the first pulsed light and the polarization direction of the second pulsed light are different from each other;

a multiplexer that multiplexes the first pulsed light and the second pulsed light;
the light amplification device according to claim 15 to which the first pulsed light and the second pulsed light, having exited the multiplexer element enter; and
a wavelength conversion unit that converts a wavelength of the first pulsed light having exited the second optical fiber and entered therein.

17. The light amplification device according to claim 1 , wherein:
a peak intensity of the second pulsed light entering the second optical fiber is lower than a peak intensity of the first pulsed light entering the second optical fiber or is zero.

18. The light amplification device according to claim 1 , wherein:
a sign of phase modulation generated in the first pulsed light through propagating in the first optical fiber and a sign of phase modulation generated in the first pulsed light through propagating in the second optical fiber are opposite from each other.

19. The light amplification device according to claim 18 , wherein:
an absolute value of phase modulation generated in the first pulsed light through propagating in the first optical fiber and an absolute value of phase modulation generated in the first pulsed light through propagating in the second optical fiber are substantially equal.

20. The light amplification device according to claim 1 , wherein:
at the first optical fiber, phase modulation occurs in the first pulsed light due to cross phase modulation caused by the second pulsed light;
at the second optical fiber, phase modulation occurs in the first pulsed light due to self-phase modulation; and
the phase modulation occurring in the first pulsed light at the second optical fiber is diminished wi

Assignees

• Nikon Corp

Inventors

• Tokuhisa Akira

Classifications

• G02F1/3532 Primary

  Arrangements of plural nonlinear devices for generating multi-colour light beams, e.g. arrangements of SHG, SFG, OPO devices for generating RGB light beams · CPC title

• G02F1/354

  Third or higher harmonic generation · CPC title

• H01S3/10023 Primary

  by functional association of additional optical elements, e.g. filters, gratings, reflectors · CPC title

• H01S5/0092

  for nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity · CPC title

• G01N2021/95676

  Masks, reticles, shadow masks · CPC title