LASER SCANNER BASED ON SWITCHING FILMS

Abstract

A new Laser scanner system does replace all known laser scanner systems, that either are galvanometer based or not. It makes possible to steer a beam of even high intensity very precisely in one or two dimensions. The system can deflect a beam in very fine steps (deflection angles), with a repetition rate of potentially better than even some GHz.

A possible embodiment includes a cascade of deflection elements, that are based on switching (thin) films. The switching films might be metallic films, or stacks of alternating dielectric films, that change their optical properties under switching electrical loads (planar areas of sufficient dimensions that are switching within ns) and become highly reflectiveto the order of 99,999%. Even other reflective, fast switching films can be usedas long as the highly reflective switching state of the layer (film) is used to select the direction of reflection/deflection of the laser beam. Said film would otherwise be in its state of very high transmission and would let the beam pass throughto some next switching layer that would reflect the beam to a slightly different direction.

Even adaptive wavefront correction can be achieved by the use of switching films, that in addition to the core idea and concept for the laser scanner are arranged in ay matrix, like a CCD, hereby granting the high throughput that might be necessary for a GHz laser scanner adaptive wavefront correction. Possible other applications of such a distortion correction elements exist many in adaptive optics.

From beam steering in laser machining to bar code scanners, to laser based tv systems the proposed system brings technology into existence that is orders of magnitude faster than what is in use right now. Especially in the area of laser based machining and production, it would be possible to produce with a far higher throughput and precision than with conventional galvanometer based systems.

Claims

1. a laser scanning/deflection system comprising: a sequence (of preferably three) deflection elements with varying total tilt angle for the x or one direction) deflection; subsequently the use of a sequence (of preferably three) deflection elements with varying total tilt angle for the y (other direction) deflection; said deflection elements for x, and similarly for y, being traversed by a laser beam by leaving the first and entering the second and subsequently leaving the second and entering the following deflection elements and thereby being deflected with finer further deflections stemming from layers that have smaller tilt angles towards each other in the second and subsequent deflection elements; said deflection elements deflecting an incoming laser beam to a discrete set of possible output beams that are tilted towards each other by using a sequence of tilted switching layers in the deflection element, through which the beam passes by and is deflected at the appropriate layer with the appropriate tilt angle; said layers rapidly switched on or off by electricity (or by other means, e.g. light) to rapidly change their optical properties from totally transparent to totally reflective; said switching of layers furnishing the selection of the appropriate layer and therefore appropriate tilt angle, by having switched all layers transparent except the one that deflects the beam to the wanted deflection angle/direction; said deflection elements optionally including a blocking (switchable) absorber layer in front of the sequence of reflective layers;

2. a laser scanning system according to claim 1.) comprising: optically induced switching layers made possible without electrodes by employing a laser beam that targets individual switching filmsas a possible nonelectronic alternative for switching the switching films;

3. a laser scanning system according to claim 1.) comprising: switching layers, that are made of metallic optical switches;

4. a laser ng system according to claim 1.) comprising: switching layers that are made of a far more reflective dielectric optical switch (for example a chalcogenide optical switch might be used for one of the dielectric materials A or B in a alternating ABABABABAB dielectric layer setup); switching layers that are made by some other eletricallyor by other means switchableplanar, thin layer;

5. a laser scanning system according to claim 1.) comprising: switching layers, that include phase changes in a fluid medium, that rapidly build up a highly reflective membrane on being electrically switched with selectable electrode lines; said membrane having a tilt angle that depends on firing up a specific selection of possible electrodes in the phase change medium;

6. a switching layer system according to claim 3.), 4.) or 5.) optionally comprising: a blocking (switchable) absorber or deflection layer in front of the reflective layer, that absorbs or deflects the incoming laser beam;

7. a laser scanning system according to claim 1.) comprising: a deflection element for the purpose of adding optical depth to the traversed optical depth of the deflected laser beam, so that all deflected beams would have the same intensity, on leaving the scanner system; said deflection element being made of a sequence of switching layers that are not tilted towards each other, contrary to the ones employed for claim 1.);

8. an adaptive optics element (stack) comprising: a combination of m switching films (xy matrices of switching films), and transparent layersspacersof various thickness; said stack of in combinations of films and transparent layers covering various overall lengths, eg. a stack covering the dozens of micrometer range (or even more for a four stacks cascade setup), then a second stack with smaller spacers covering the range up to eg. 3 micrometers and a last one covering the range of eg. 200 nm; said stack of combinations of films for the range of 200 nm comprising: possibly only switching films, because the switching film itself covers the needed depth/thickness of approximately 15 nm (13 pieces of 15 nm thickness make 195 nm), at least in the case of a metallic film; said xy resolved matrices of switching films comprising: a separation tot he next matrices in the stack by using possible fixed length transparent spacers in between; said xy matrices comprising a means to: correct the phase of an incident laser beam on a per pixel basis, said correction adding up to a total amount of correction on passing through the sequence of phase correction stacks on sequentially entering the stacks with higher overall length, leaving them and subsequently entering the ones with ever smaller overall lengthor phase correction ability. Hereby phase correction adds up to the necessary amount of phase correction with fine enough discrete phase correction steps; said xy matrices comprising: switching films that might include electrodes that are made of highly transparent metallic materialto make electrical switching possible without distorting the beam; said xy matrices optionally making switching possible without electrodes by employing a laser beam that targets individual pixels on the xy matrixas a possible nonelectronic alternative to switch the optical properties of the switching layers;

9. an adaptive optics element (stack) comprising: (stacks) of a combination of switching films (xy matrices), and transparent layers of variable thickness, whereby every stack covers a certain range of discrete deflection angles of the laser beam by using tilted switching mirrorssimilar to claim onewith the difference that the deflecting area is a xy resolved matrix that can deflect the beam on a per pixel basis; said pixel spanning an area of some m times some m, possibly subdivided to switch on only the parts of the pixel, that do not mask a possible reflection from a deeper xy matrix pixel reflection; said xy resolved matrices are stacked one on the other with possible spacers inbetweenalthough because of masking effects it is preferred to have minimum distance between consecutive xy matrices; said sequence having the least deflection xy matrix on the deepest level and employing the higher deflections on higher levels (definition: level of xy matrices closer to the incident beam is higher); said switching films might include electrodes that are made of highly transparent metallic materialto make electrical switching possible without distorting the beam; said switching might be possible without electrodes by employing a laser beam that targets individual pixels on the xy matrixas a possible nonelectronic alternative;

10. a method for the laser scanning system according to claim 1.) of scanning through all xy directions of possible beam deflections to measure the intensity of the leaving beam to precompute correction values/settings for the optical depth correction system that is employed in claim 1.); said settings are going to be fed into the system that corrects optical depth for use in the normal operation of the scanner system in the GHz regime (from MHz to dozens of GHz); said feeding of correction values happens synchronous with setting the xy values for the scanner.

11. a method for the adaptive optics system according to claim 8.) of scanning through all xy directions of possible beam deflections to measure the wavefront phase distortion of the leaving beam to precompute correction values/settings for the phase correction system that is employed in claim 8.); said settings are going to be fed into the wavefront phase correction for use in the normal operation of the scanner system in the GHz regime (from MHz to dozens of GHz); said feeding of correction values happens synchronous with setting the xy values for the scanner.

12. a method for the laser scanning system according to claim 9.) of scanning through all xy directions of possible beam deflections to measure the wavefront distortion and intensity of the leaving beam to precompute correction values/settings for the system that is employed in claim 9.); said settings are going to be fed into the wavefront deflection angle correction for use in the normal operation of the scanner system in the GHz regime (from MHz to dozens of GHz); said feeding of correction values happens synchronous with setting the xy values for the scanner.

Description

BRIEF DESCRIPTION OF THE OBJECTS

[0027] In order to more fully understand the objects, the following detailed description of the illustrative embodiments should be read in conjunction with the accompanying drawings, wherein:

[0028] FIG. 1 depicts a deflection element, that consists of a sequence of tilted switching layers (electrochromic, or dichroitic dielectrically switching or other, preferably electrically switching layers, element No. 2). Element No. 1 is such a stack of tilted layers, that comprises a deflection element. Pos. 3 depicts an incoming beam, Pos. 4 the axis of incidence and Pos. 5 the reflected beam.

[0029] FIG. 2 depicts a possible stacked sequence of layers, that comprise the switching layer. Pos. 1 shows the switching layer in its completeness. Pos. 2 shows a sublayer of the switching layer, that might follow an ARAB stacking sequence, with material A being made of dielectric material 1, and B being made of dielectric material 2. The layer Pos. 3 might be an absorber layer. Pos. 4 depicts a magnified view of the switching layer Pos. 1

[0030] FIG. 3 shows the sequence of the span of the deflection angle of consecutive deflection elements for a possible cascaded embodiment of the deflecting elements. In Pos. 1 a deflection element with bigger deflection angle span is shown. In Pos, 2 a deflection element with a correspondingly smaller span is shown, where the deflection sweeps a range of angles that corresponds to the span covered going from one switching layer to the next on the deflection element with Pos. 1 (take notice of the angle .sub.0. It is obvious that the tilting of the switching layers in the first (Pos. 1) deflection element A1 (Pos. 3) is bigger than tilting of the switching layers (Pos. 4) in the second deflection element A2 (Pos. 2).

[0031] FIG. 4 depicts a possible spatial arrangement and sequence of the deflection elements (here A1 and A2) to deflect a laser beam in one, or by using two sequences of deflection elements in two directions. Pos, 1 shows an incoming laser beam, with a first reflection on Pos. 1 and a second reflection on Pos. 2. Pos, 4 shows the finer succession of deflection angles after passing through two deflection elements A1 and A2. An even finer sequence would be possible on similarly using 3 deflection elementsthe span (or tilting) would be even smaller in the case of a third deflection element. Proper arrangement/distances of the deflection elements and dimensioning leads to an acceptable uniform overall deflection at Pos. 4, that in the case of the drawing shows a gap between two depicted reflected laser beam bunches, that of course has to be taken account of by proper optical/mechanical engineering. The aim is a uniform spacing of the deflected beams over the whole range of possible deflection.

[0032] FIG. 5 depicts a possible cut of a spatial arrangement of a deflection distortion element that is based on a combination of deflection elements in ay matrix, that deflect the beam on a per pixel basis. Pos. 1 shows the complete stack. The stack shows a setup that favors only one deflection direction (here deflection up). Setups with deflections up and down are similarly possible. Pos. 2 is an individual switching mirror element/pixel of size eg. 10 m times 10 m. The laser beam would be reflected in various depths/layers to correct possible deflection distortions on a per pixel basis. The xy matrices shall be close to each other to minimize masking situations for reflections from deeper layers on higher layers. Even individual pixels shall be further broken down to switcheable areas, that can be switched on and off according to possible maskings that might occur. Switching layers in deeper layers shall have smaller deflection tilts in relation to the incident laser beam. A possible masking configuration is depicted with the deeper layer on Pos. 3 and the higher adjacent layer on Pos. 4. A reflected beam would cut a substantial fraction of the higher adjacent pixel/layer on Pos. 4.

[0033] FIG. 6 depicts a possible cut of a spatial arrangement of a phase distortion correction element that is based on a combination of deflection elements in ay matrix, that reflect the beam on a per pixel basis. Pos. 1 shows the complete stack. Pos. 2 shows an individual switching mirror element of size eg. 10 m times 10 m. The laser beam would be reflected in various depths to correct possible phase/optical path differences.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0034] By using elements as depicted in FIG. 1 that either are made of single layer switching films or multiple layer dielectric switching films as shown on FIG. 2 it is possible to quickly change the optical properties of the switching films from transparent to reflective. A mechanism and a setup is found that makes it possible to deflect a laser beam to ever more refined deflection angles by leaving one deflection element and entering the next. The possible angular span, and granularity of the deflection is made possible due to the choice of a cascade of deflection elements, each of which includes a sequence of switching layers, that preserve a fixed tilt angle going from one to the next switching layer (FIG. 3,4). The selection of the switching layer, by switching it reflective and all the other layers transparent, makes it possible to deflect the laser beam into a wanted deflection direction. Special care has to be taken to warrant a proper interalignment of the deflected beams, that leave the following/next/subsequent deflection element in a setup. As clearly depicted in FIG. 4 the deflection element A2 has to be brought much closer to A.sub.1 to put the reflected beam of Layer 2 of A.sub.1 much closer to the reflections of the reflected beam of Layer 1 of A.sub.1 on Layer 1 of A.sub.2 to match the deflections of the reflection of Layer 1 of A.sub.1 (on A2) with the deflections of the reflection of Layer 2 of A.sub.1 (on A2). This is possible for certainto be computeddistances of A.sub.1 to A.sub.2, certain maximum tilt angles, certain laser beam widths, certain layer thicknesses and distances. The wavefront distortion of the leaving laser beam is corrected with the same switching layer technologywhereby the layers now are xy matrices of eg. m huge pixels. These pixels might be tilted switching layers, that might even be switched on and off only partially to prevent masking effects (FIG. 5). All this lies in the realm of state of the art MEWS technology even for the required accuracy of tilt angles, although it has to be taken into account that planarity of the used layers/pixels has to be maintained while a means has to be used that delivers accurately tilted layers/pixels in a xy matrix. There is some flexibility in the choice of the size of the pixels, as much as in the choice of the possible range and number of distinct deflection angles for the deflection angle distortion correction, to make the production of these matrices tractable. Mismatches in phase can similarity be corrected with a stack of xy matrices of switching layers (FIG. 6).

REFERENCES

[0035] Stefanovich et al., Electrical switching and Mott transition in VO.sub.2, J. Phys.: Condens. Matter 12 8837 [0036] Myoung-Jae Lee et al., A plasma-treated chalcogenide switch device for stackable scalable 3D nanoscale memory, Nature Communications volume 4, Article number: 2629