INTERFEROMETER SYSTEM AND USE THEREOF

• US 20190323821A1
• Filed: 12/21/2017
• Published: 10/24/2019
• Est. Priority Date: 12/22/2016
• Status: Active Grant

• Current Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Original Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Inventors: VISSER, Huibert, VAN BRUG, Hedser
• Granted Patent: US 11,143,498 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 2290/35 Mechanical variable delay line
• CPC Class Codes: G01B 9/02024 Measuring in transmission, i.e. light traverses the object
• CPC Class Codes: G01B 9/02072 by calibration or testing of interferometer
• CPC Class Codes: G01N 21/45 using interferometric methods; using Schlieren methods

Abstract

Interferometer system, including optical means (2, 3, 4, 5) arranged for directing light along a first interferometer path and (separate) second interferometer path, and for combining the light for allowing interferometry, characterized in that the first interferometer path (PI) is provided with a first light transmitting structure (10) having a rotational position that is adjustable with respect to an optical axis of the first path.

Claims

1. An interferometer system, including optical means arranged for directing light along a first interferometer path and separate second interferometer path, and for combining the light for allowing interferometry,

wherein the first interferometer path is provided with a first light transmitting structure having a rotational position that is adjustable with respect to an optical axis of the first path.

2. The interferometer system according to claim 1, including displacement means for automatically removing the first light transmitting structure from the first path.

3. The interferometer system according to claim 1, wherein the system includes a first translational support structure, configured for removably holding the light transmitting structure.

4. The interferometer system according to claim 1, including a drive means for adjusting the rotational position of the first light transmitting structure, the drive means for example including a rotational support structure for rotationally holding the light transmitting structure.

5. The interferometer system according to claim 3, wherein the first translational support structure is integrated with a rotational support structure of the drive means.

6. The interferometer system according to claim 3, wherein the first translational support structure is configured for removably holding the light transmitting structure by removably holding the respective rotational support structure of the drive means.

7. The interferometer system according to claim 3, wherein first translational support structure is adjustable between an operating position wherein the first light transmitting structure is in the optical path and a removed position wherein the first light transmitting structure is removed from the optical path.

8. The interferometer system according to claim 1, wherein the first light transmitting structure includes a light incident surface, as well as a light exit surface that extends substantially in parallel with the light incident surface.

9. The interferometer system according to claim 1, wherein a position of the first light transmitting structure can be adjusted over an angle of at least zero degrees between at least a first rotational and second rotational position with respect to the optical axis of the first path, wherein the first light transmitting structure is preferably dimensioned such that it receives all light that traverses the respective first interferometer path, during operation, in both rotational positions.

10. The interferometer system according to claim 1, wherein the first light transmitting structure has at least one rotational position with respect to the optical axis of the first path, in which the optical axis extends substantially normally onto an incident surface and/or exit surface of that structure.

11. The interferometer system according to claim 1, wherein the second interferometer path is provided with a second light transmitting structure, for example having a rotational position that is not adjustable with respect to an optical axis of the first path.

12. The interferometer system according to claim 1, wherein the second interferometer path is provided with a second light transmitting structure for locally providing a second optical path difference, the second optical path difference being larger or smaller than a first optical path difference that is provided by the first light transmitting structure in the respective first interferometer path.

13. The interferometer system according to claim 11, wherein the second light transmitting structure is removable from the respective second path, and is in particular movable between an operating position in the optical path, and a removed position wherein the second light transmitting structure is removed from the respective optical path.

14. The interferometer system according to claim 11, wherein the system includes a translational support structure, configured for removably holding the second light transmitting structure.

15. The interferometer system according to claim 11, including controlling means arranged for setting a position of the second light transmitting structure or a respective translational support structure.

16. The interferometer system according to claim 1, wherein the first light transmitting structure is made of glass, for example including one or more glass plates or one or more glass layers.

17. The interferometer system according to claim 1, wherein the system has a Mach-Zehnder or a Michelson interferometer layout.

18. The interferometer system according to claim 1, including interferometer calibration means for setting a rotational position of the first light transmitting structure based on a test signal, for example light having a predetermined light spectrum or spectrum component.

19. An interferometry method comprising:

directing light beams along a first interferometer path and a second interferometer path, and combining the beams allowing interferometry, e.g. utilizing an interference pattern detecting means, wherein a rotational position of a first light transmitting structure is set to a predetermined position for locally providing a respective optical path difference.

20. The method according to claim 19, including a first calibration step wherein the light beams are directed along the first interferometer path and second interferometer path, without the presence of the first light transmitting structure in the first path.

21. The method according to claim 20, wherein the system includes a first translational support structure, configured for removably holding the first light transmitting structure, wherein during the first calibration step the first translational support structure has been adjusted from an operating position wherein the first light transmitting structure is in the optical path to a removed position wherein the first light transmitting structure is removed from the optical path.

22. The method according to claim 19, wherein during the first calibration step, broadband light or white light is directed along the first interferometer path and second interferometer path.

23. The method according to claim 19, including a second calibration step wherein light beams are directed along the first interferometer path and second interferometer path, with the presence of the first light transmitting structure in the first path and optionally with the presence of a second light transmitting structure in the second path,

wherein light is used having a predetermined light spectrum or spectrum component, for example light that is passed through a test fluid before entering the interferometer paths, wherein a rotational position of the first light transmitting structure is set based on analysis of a detected interference pattern concerning the combined beams, particularly for optimizing the interference pattern.