Beam combiner

• US 4,283,116 A
• Filed: 05/02/1979
• Issued: 08/11/1981
• Est. Priority Date: 04/22/1977
• Status: Expired due to Term

• Current Assignee: Jersey Nuclear-Avco Isotopes Incorporated
• Original Assignee: Jersey Nuclear-Avco Isotopes Incorporated
• Inventors: Weis, John A.
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US06/035,223
• Time in Patent Office: 832 Days
• Field of Search: 350/174, 350/171, 350/169, 350/285, 350/6.9
• US Class Current: 359/204.1
• CPC Class Codes: B01D 59/34 Separation by photochemical methods
• CPC Class Codes: G02B 27/147 using averaging effects by spatially variable reflectivity on a microscopic level, e.g. polka dots, chequered or discontinuous patterns, or rapidly moving surfaces G02B27/1086 takes precedence
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108

Abstract

An optical commutation system for commutating pulsed radiation between a common path of relatively high pulse rate and plural, closed spaced, slowly diverging paths on which the pulses are distributed. The system may thus act as a combiner or decombiner. The system employs a reflective or refractive optical element which is driven to produce a very slight oscillation in the orientation of the refractive or reflective surface of the element typically ranging over only a few degrees. The angle of oscillation is kept as small as possible, being only large enough to resolve or separate the radiation pulses on the slowly diverging paths. The very slight angular variation between adjacent ones of the diverging paths permits a large number of beams to be packed together in the bundle of diverging paths, but because of the slight angular variation, only a small angular scan resulting from the finite pulse duration is experienced. This can be kept well within acceptable limits for use with long path lengths.

Claims

1. A system for combining beams of pulsed radiation comprising:

a plurality of pulsed radiation sources for providing spatially separate beams of radiation pulses in a time sequence;

the radiation pulses having a finite time duration;

the beams of radiation being inclined with respect to and distributed around a central axis so as to lie in a conical surface whose axis is the central axis;

each of said beams of radiation being inclined from said axis by a predetermined angle which is a small fraction of a radian;

means for receiving the sequence of spatially separate beams of radiation pulses at substantially their point of intersection with said central axis to deflect the separate beams of radiation pulses onto a common path over said finite time duration;

said central axis and said common path being inclined to and therefor separate from each other.

2. The system of claim 1 wherein said predetermined angle is less than one degree.

3. The system of claim 1 wherein:

each of said beams of radiation is characterized by having an angle of divergence and a predetermined time duration; and

said means for receiving includes means for limiting the angular motion of said pulses directed along the common path over each pulse duration to be less than the angle of divergence thereof.

4. The system of claim 1 wherein the means for receiving comprises a reflecting surface.

5. The system of claim 4 wherein the receiving means causes an axis orthogonal to the reflecting surface to follow a conical surface angled about its axis by a small fraction of a radian.

6. The system of claim 5 wherein the means for receiving further comprises means for rotating the reflective surface.

7. The system of claim 6 wherein the apex of the conical distribution of beams lies generally in the plane of the reflective surface.

8. The system of claim 7 wherein the apex contacts the reflective surface at a point remote from the axis of rotation of the reflective surface.

9. The system of claim 7 wherein the radiation sources comprise pulsed lasers.

10. The system of claim 7 wherein the means for receiving further comprises means for synchronizing the rotation of the reflective surface with the radiation pulses from each of the pulsed radiation sources to reflect each received pulse along the common path.

11. The system of claim 10 wherein the pulsed radiation sources emit pulses sequentially in an order corresponding to the ordering of beams of pulsed radiation around the central axis.

12. The system of claim 11 wherein the reflecting surface rotates one revolution during a complete sequence of pulses from each of the pulsed radiation sources.

13. The system of claim 7 further comprising:

a second plurality of pulsed radiation sources providing spatially separate beams of radiation pulses in a sequence;

the radiation pulses from the second plurality of pulsed radiation sources having a finite time duration;

the beams of radiation pulses from the second plurality of pulsed radiation sources being distributed around and inclined with respect to a second central axis and intersecting the second axis at substantially the same point, such that the beams of radiation from the second plurality of pulsed radiation sources lie generally in a second conical surface about the second axis;

the means for receiving being operative to direct the separate beams of radiation from the second plurality of pulsed radiation sources along a second generally common path different from the first common path.

14. The system of claim 1 wherein the means for receiving comprises an optically transmissive refracting means having an index of refraction differing from that of the surrounding environment and positioned to receive the beams of pulsed radiation for deflecting the path of the beams of pulsed radiation to direct the separate beams of radiation pulses along the generally common path.

15. The system of claim 14 wherein the refracting means has first and second planar surfaces whose normals are inclined with respect to the common path at equal angles.

16. The system of claim 15 wherein the beams of pulsed radiation enter the refracting means at the second surface and leave the refracting means at the first surface thereof.

17. The system of claim 16 wherein the second surface is located substantially at the apex of the conical surface.

18. The system of claim 14 wherein the means for receiving further comprises means for rotating the refracting means about an axis of rotation.

19. The system of claim 18 wherein the axis of rotation is parallel to the common path.

20. The system of claim 14 wherein the means for receiving further comprises means for synchronizing the rotation of the refracting means with the radiation pulses coming from each of the pulsed radiation sources such that each pulse is directed along the common path by the refracting means.

21. The system of claim 20 wherein the pulsed radiation sources emit pulses substantially in the order that the radiation beam from each is arranged around said central axis.

22. The system of claim 21 wherein the refracting means rotates once for each complete sequence of pulses from the pulsed radiation sources.

23. The system of claim 22 wherein the beams of radiation pulses comprise pulses of collimated electromagnetic radiation.

24. The system of claim 20 wherein the sources of pulsed radiation comprise pulsed lasers.

25. The system of claim 1 wherein the means for receiving consists of a single reflecting surface.

26. The system of claim 25 wherein the reflecting surface is rotated about an axis inclined with respect to the normal to the reflecting surface.

27. Apparatus for combining a plurality of beams of pulsed radiation into a single beam of pulsed radiation and for splitting a single beam of pulsed radiation into a plurality of beams of pulsed radiation, comprising:

means for receiving a plurality of beams of pulsed radiation, the beams of pulsed radiation being distributed around and inclined by a small fraction of a radian with respect to a central axis and intersecting the central axis at substantially one point, such that the beams of radiation lie generally in a conical surface about the central axis, and for directing the separate beams of radiation pulses along a generally common path, said central axis and said common path being inclined to and therefor separate from each other;

the means for receiving being further operative to receive a single input beam of sequenced radiation pulses and to direct individual pulses thereof along a plurality of separate paths so as to provide spatially separate beams of radiation pulses, the separate paths being distributed around and inclined by a small fraction of a radian with respect to an output axis and emanating from substantially one point thereon so that the resulting plurality of beams of radiation lie generally in a conical surface whose axis is the output axis, said output axis and the path of said single beam being inclined to and therefor separate from each other.

28. The apparatus of claim 27 wherein the means for receiving further comprises:

a reflecting surface; and

means for rotating the reflective surface about an axis inclined with respect to the normal to the reflecting surface such that the normal traces a cone;

the intersection of the axis of rotation and the reflective surface being located substantially at the apexes of the conical distributions of beams.

29. The apparatus of claim 27 wherein the means for receiving comprises:

an optically transmissive refracting means having an index of refraction differing from that of the surrounding environment and operative for deflecting the beams of pulsed radiation; and

means for rotating the refracting means about an axis parallel with the common path.

30. In a system having a repeating sequence of time points each defining a time of occurrence of a radiation pulse in a sequence of radiation pulses each of a finite time duration, a dynamic optical system for providing an angular transformation of said sequence of radiation pulses between a first axis defining a common path of positionally superimposed radiation pulses and a plurality of spatially separate radiation paths each inclined to a central axis and distributed about said central axis, said system comprising:

an optical element having at least one surface for providing radiation deflection;

said surface being positioned to intersect said first axis and said central axis;

means for cylically varying the angle at which said surface of said element intersects said first axis by a bounded angle which is a small fraction of a radian to maintain the transformation between said common path and the corresponding spatially separate path during the finite time duration;

said central axis and said common path being inclined to and therefor separate from each other;

means for defining said sequence of time points;

said cylically varying means including means for synchronizing the cylical variation in the intersection angle of said surface to provide a predetermined angle of intersection for said surface for each of said time points in said sequence of said time points.

31. The dynamic optical system of claim 30 wherein said optical element includes a mirror.

32. The dynamic optical system of claim 31 wherein said optical element includes a refractive element.

33. The dynamic optical system of claim 30 wherein said means for cyclically varying includes means for rotating said optical element.

34. The dynamic optical system of claim 30 wherein said bounded angle is no more than one degree.

35. The dynamic optical system of claim 30 further including:

means for generating a plurality of time-sequenced radiation pulses directed along said plurality of spatially separate radiation paths toward said optical element for combining into a plurality of radiation pulses of augmented pulse rate along said common path.

36. A system for combining beams of pulsed radiation comprising:

a plurality of pulsed radiation sources for providing spatially separate beams of radiation pulses in a time sequence;

the radiation pulses having a finite time duration;

the beams of radiation being inclined with respect to and distributed around a central axis so as to lie in a conical surface whose axis is the central axis;

each of said beams of radiation being inclined from said axis by a predetermined angle which is a small fraction of a radian;

means for receiving the sequence of spatially separate beams of radiation pulses at substantially their point of intersection with said central axis to deflect the separate beams of radiation pulses onto a common path over said finite time duration;

each of said beams of radiation being characterized by having an angle of divergence and a predetermined time duration; and

said means for receiving including means for limiting the angular motion of said pulses directed along the common path over each pulse duration to be less than the angle of divergence thereof.

37. A system for combining beams of pulsed radiation comprising:

a plurality of pulsed radiation sources for providing spatially separate beams of radiation pulses in a time sequence;

the radiation pulses having a finite time duration;

the beams of radiation being inclined with respect to and distributed around a central axis so as to lie in a conical surface whose axis is the central axis;

each of said beams of radiation being inclined from said axis by a predetermined angle which is a small fraction of a radian;

means for receiving the sequence of spatially separate beams of radiation pulses at substantially their point of intersection with said central axis to deflect the separate beams of radiation pulses onto a common path over said finite time duration;

said means for receiving comprising a rotating reflecting surface causing an axis orthogonal to the reflecting surface to follow a conical surface angled about its axis by a small fraction of a radian;

the apex of the conical distribution of beams lying generally in the plane of the reflective surface and contacting the reflective surface at a point remote from the axis of rotation of the reflective surface.