Dispersion adjustment units and methods of use

Patent metadata

Field	Value
Publication number	US-11205883-B2
Application number	US-201816220380-A
Country	US
Kind code	B2
Filing date	Dec 14, 2018
Priority date	Jun 15, 2016
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

The invention relates to dispersion adjustment units for electromagnetic radiation having a spectral width, e.g., for laser pulses. The dispersion adjustment unit includes at least one dispersive element for producing angular dispersion in an angular dispersion region limited by two interaction regions of the electromagnetic radiation with the at least one dispersive element. In the angular dispersion region, individual spectral components of the electromagnetic radiation are associated with optical paths extending at an angle to one another. Furthermore, the dispersion adjustment unit includes an optical unit that is arranged in the angular dispersion region and includes an optical element that transmits the electromagnetic radiation. The optical element effects an incidence-angle-dependent parallel offset of the individual spectral components of the electromagnetic radiation with respect to the propagation of the individual spectral components before and after the optical unit.

First claim

What is claimed is:

1. A dispersion adjustment unit for electromagnetic radiation having a spectral width, comprising:
at least one dispersive element comprising one or more of an optical grating, a prism, or a grism, wherein the at least one dispersive element is configured and arranged to generate angular dispersion in an angular dispersion region, delimited by a first interaction region and a second interaction region where the electromagnetic radiation interacts with the at least one dispersive element,
wherein after the electromagnetic radiation interacts with the first interaction region individual spectral components of the electromagnetic radiation fan out along optical paths that run at an angle to one another; and
wherein after the electromagnetic radiation interacts with the second interaction region, the optical paths of the individual spectral components of the electromagnetic radiation are parallelized, yet remain displaced from one another; and

an optical unit arranged within the angular dispersion region and comprising an optical element transmitting the electromagnetic radiation, wherein the optical element produces an incidence angle dependent parallel offset of the individual spectral components of the electromagnetic radiation with respect to the propagation of the individual spectral components before and after the optical unit.

2. The dispersion adjustment unit of claim 1 , wherein the optical unit has a plane incidence surface and a plane exit surface that are arranged parallel to each other.

3. The dispersion adjustment unit of claim 2 , wherein with respect to the incidence surface and the exit surface, an incidence angle and an exit angle of the optical paths of individual spectral components are identical due to the substantial parallelism of the incidence surface and the exit surface.

4. The dispersion adjustment unit of claim 2 , wherein the incidence surface and the exit surface are arranged at a distance from each other, and wherein the material of the optical element has a thickness of at least about 0.1 mm to about 10 mm.

5. The dispersion adjustment unit of claim 2 , wherein the optical element is rotatably mounted with respect to the beam path for adjusting the angular position of the optical element, so that an incidence angle and an exit angle of the optical paths are adjustable with respect to the incidence surface and the exit surface of the optical element, respectively.

6. The dispersion adjustment unit of claim 2 , wherein at least one of the incidence surface and the exit surface comprises an antireflection coating.

7. The dispersion adjustment unit of claim 1 , wherein the optical element comprises at least one plane-parallel plate or a pair of oppositely displaceable wedges.

8. The dispersion adjustment unit of claim 1 , wherein the optical unit further comprises an adjusting device configured to change the parallel offset of the individual spectral components.

9. The dispersion adjustment unit of claim 8 , wherein the adjusting device is configured to change the spatial orientation of the optical element in the angular dispersion region for changing the parallel offset.

10. The dispersion adjustment unit of claim 8 , wherein the optical element comprises at least one plane-parallel plate, which has a planar incidence surface and a planar exit surface that are arranged parallel to each other, and the adjusting device is configured to change an angular position of the at least one plane-parallel plate for changing the parallel offset.

11. The dispersion adjustment unit of claim 8 , wherein the optical element comprises a multi-wedge device and the adjusting device is configured to change at least one of a thickness and an angular position of the multi-wedge device for changing the parallel offset.

12. The dispersion adjustment unit of claim 8 , wherein the optical element comprises an electro-optical modulator and the adjusting device is configured to change a refractive index of the electro-optical modulator for changing the parallel offset.

13. The dispersion adjustment unit of claim 8 , wherein the optical element comprises a pair of acousto-optical modulators, and the adjusting device is configured to change a diffraction parameter of the pair of acousto-optical modulators for changing the parallel offset.

14. The dispersion adjustment unit of claim 8 , wherein the adjusting device is configured to set a dispersion contribution of the dispersion adjustment unit in dependence on at least one of a pulse duration-dependent measurement signal, a pulse power parameter, a peak pulse power parameter, and a pulse energy parameter.

15. The dispersion adjustment unit of claim 1 , wherein the optical element is adjustable independently of the at least one dispersive element in at least one of its positions and orientations in the beam path with respect to the at least one dispersive element.

16. The dispersion adjustment unit of claim 1 , wherein the optical element is mounted rotatably about a rotation axis running essentially perpendicularly to a fan-out-plane spanned by the optical paths extending at an angle to one another.

17. The dispersion adjustment unit of claim 1 , wherein the optical element has a plane incidence surface and a plane exit surface arranged parallel to one another and perpendicular to a fan-out-plane spanned by the optical paths extending at an angle to one another.

18. The dispersion adjustment unit of claim 1 , wherein the material of the optical element is quartz, YAG, sapphire, or SF 10 .

19. The dispersion adjustment unit of claim 1 , wherein a rotation of the optical element or a changing of at least one of a thickness, a refractive index, and a diffraction parameter of the optical element causes a change of the dispersion produced by the dispersion adjustment unit with a constant position of the at least one dispersive element or with a substantially constant distance between the interaction regions.

20. The dispersion adjustment unit of claim 1 , further comprising:
at least one focusing element forming an optical telescope arranged between the interaction regions of the at least one dispersive element, wherein the optical element is arranged in the beam path section between one of the focusing elements and the adjacent interaction region of the at least one dispersive element, or
a reflection element or a roof edge mirror or a deflection prism for back reflection of the optical paths with a parallel displacement in one direction, wherein the reflection element or the roof edge mirror or the deflection prism is arranged between the interaction regions of the at least one dispersive element.

21. The dispersion adjustment unit of claim 1 , wherein the optical unit comprises a plurality of optically transmitting plates, which are rotatably mounted in the beam path between the interaction regions of the at least one dispersive element and are arranged rotated in the same direction or in opposite rotation directions in the beam path.

22. The dispersion adjustment unit of claim 1 , further comprising any one or more of:
an optical folding element, a deflection prism, or a deflection mirror unit, for guiding the beam path back through the interaction regions of the at least one dispersive element and the optical unit; and
a second pair of interaction regions of at least one further dispersive element with another optical unit correspondingly arranged in the beam path.

23. The dispersion adjustment un

Assignees

• Trumpf Laser Gmbh

Inventors

• Budnicki Aleksander
• Scelle Raphael

Classifications

• H01S3/0014

  Monitoring arrangements not otherwise provided for (photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003) · CPC title

• H01S3/0057 Primary

  Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108) · CPC title

• H01S3/1003

  tunable optical elements, e.g. acousto-optic filters, tunable gratings · CPC title

• H01S3/10053

  Phase control · CPC title

• B23K26/064

  by means of optical elements, e.g. lenses, mirrors or prisms · CPC title