Laser-based phase plate image contrast manipulation

Patent metadata

Field	Value
Publication number	US-11101101-B2
Application number	US-202016855536-A
Country	US
Kind code	B2
Filing date	Apr 22, 2020
Priority date	May 15, 2019
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

Methods and systems for implementing laser-based phase plate image contrast enhancement are disclosed herein. An example method at least includes forming at least one optical peak in a diffraction plane of an electron microscope, and directing an electron beam through the at least one optical peak at a first location, where the first location determines an amount of phase manipulation the optical peak imparts to an electron of the electron beam.

First claim

What is claimed is:

1. An apparatus for image contrast optimization, the apparatus comprising:
an electron source coupled to provide an electron beam to a sample;
one or more deflectors coupled to reposition the electron beam in response to a control signal;
an optical source coupled to provide an optical beam, the optical beam a high energy optical beam;
an optical cavity coupled to receive the optical beam and to form at least one optical peak within the optical cavity, the optical cavity arranged at a diffraction plane of an electron microscope; and
a controller coupled to at least the one or more deflectors, the controller including or coupled to non-transitory computer readable medium including code that, when executed by the controller, causes the controller to:
direct, by the one or more of the deflectors, the electron beam through the at least one optical peak at a first location, wherein the first location determines an amount of phase manipulation the optical peak imparts to an electron of the electron beam.

2. The apparatus of claim 1 , wherein the first location is a peak intensity location of the optical peak.

3. The apparatus of claim 1 , wherein the first location is a location with an intensity less than a peak intensity of the optical peak.

4. The apparatus of claim 1 , wherein the at least one optical peak is formed from an optical pulse.

5. The apparatus of claim 1 , wherein the at least one optical peak is part of an optical standing wave.

6. The apparatus of claim 5 , wherein the optical source provides a continuous wave optical beam to the optical cavity to form the optical standing wave.

7. The apparatus of claim 1 , wherein the optical cavity is a near concentric Fabry-Perot cavity.

8. The apparatus of claim 1 , wherein the non-transitory computer readable medium further includes code that, when executed by the controller, causes the controller to:
direct the electron beam through the at least one optical peak at a second location, the second location being different than the first location, wherein the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the second location is different than the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the first location.

9. The apparatus of claim 1 , wherein the at least one optical peak is part of an optical standing wave, and wherein the non-transitory computer readable medium further includes code that, when executed by the controller, causes the controller to:
direct the electron beam through a second optical peak, wherein the amount of phase manipulation the second optical peak imparts to an electron of the electron beam is different than the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the first location of the at least one optical peak.

10. The apparatus of claim 1 , wherein the at least one optical peak is part of an optical standing wave, and wherein the non-transitory computer readable medium further includes code that, when executed by the controller, causes the controller to:
dynamically raster the electron beam between the first location and a second location, the second location being outside of the at least one optical peak so that there is no interaction between an electron of the electron beam and the optical beam.

11. The apparatus of claim 1 , wherein the at least one optical peak is part of an optical standing wave, and wherein the non-transitory computer readable medium further includes code that, when executed by the controller, causes the controller to:
move the electron beam along the optical standing wave to cause the electron beam to pass through a plurality of peaks and troughs of the optical standing wave, wherein interaction of the electron beam with different intensities along the scan causes the amount of phase manipulation to change based on the different intensities.

12. A method for image contrast optimization, the method comprising:
forming at least one optical peak in a diffraction plane of an electron microscope; and
directing an electron beam through the at least one optical peak at a first location, wherein the first location determines an amount of phase manipulation the optical peak imparts to an electron of the electron beam.

13. The method of claim 12 , wherein the first location is a peak intensity location of the optical peak.

14. The method of claim 12 , wherein the first location is a location with an intensity less than a peak intensity of the optical peak.

15. The method of claim 12 , wherein the at least one optical peak is formed from an optical pulse.

16. The method of claim 15 , further comprising providing the optical pulse to an optical cavity arranged at the diffraction plane of the electron microscope.

17. The method of claim 12 , wherein the at least one optical peak is part of an optical standing wave.

18. The method of claim 17 , further comprising providing a continuous wave optical beam to an optical cavity arranged at the diffraction plane of the electron microscope to form the optical standing wave.

19. The method of claim 18 , wherein the optical cavity is a Fabry-Perot cavity.

20. The method of claim 19 , wherein the Fabry-Perot cavity is near concentric.

21. The method of claim 12 , further comprising:
directing the electron beam through the at least one optical peak at a second location, the second location being different than the first location.

22. The method of claim 21 , wherein the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the second location is different than the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the first location.

23. The method of claim 21 , wherein the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the second location is the same as the amount of phase manipulation the optical peak imparts to an electron of the electron beam at the first location.

24. The method of claim 12 , further including:
dynamically rastering the electron beam between the first location and a second location, the second location being outside of the at least one optical peak so that there is no interaction between an electron of the electron beam and the optical beam.

25. The method of claim 12 , wherein the at least one optical peak is part of an optical standing wave formed at the diffraction plane, further comprising:
moving the electron beam along the optical standing wave to cause the electron beam to pass through a plurality of peaks and troughs of the optical standing wave, wherein interaction of the electron beam with different intensities along the scan imparts the amount of phase manipulation to change based on the different intensities.

Assignees

• Fei Co

Inventors

• Buijsse Bart
• Hendriksen Bas
• Dona Pleun

Classifications

• H01J37/22

  Optical {, image processing} or photographic arrangements associated with the tube · CPC title

• G01N23/20058

  Measuring diffraction of electrons, e.g. low energy electron diffraction [LEED] method or reflection high energy electron diffraction [RHEED] method · CPC title

• H01J37/222 Primary

  Image processing arrangements associated with the tube · CPC title

• H01J2237/2802

  Transmission microscopes · CPC title

• H01J2237/2614

  Holography or phase contrast, phase related imaging in general, e.g. phase plates · CPC title