JP7354060B2 - Rotating beam symmetrizer - Google Patents

Description

RELATED APPLICATIONS This application is filed at 35U. S. C. §119, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The present disclosure relates to optical devices associated with providing rotating light beams, and more particularly to bidirectional rotating light beams having optical power having a first direction of spatial rotation and optical power in a second direction of spatial rotation. The present invention relates to an optical device for providing.

The beam profile of a light beam has a significant impact on the processing performance associated with material processing performed using the light beam. For example, a light beam with an annular beam profile enables improved metal cutting, welding, and/or other types of material processing by scanning the beam along a surface. In some cases, a light beam with an annular beam shape may be generated within an optical fiber (ie, without free space optics). In such cases, the light beam produced is a rotating light beam (i.e., a light beam propagating helically within the optical fiber), providing a light beam that still has an annular beam shape after exiting the optical fiber. This rotational property of the light beam can be maintained (e.g. when the light beam exits the optical fiber), so that the laser spot projected from the optical fiber onto the workpiece is an annular beam with sharp edges and high beam quality. Show profile. Therefore, a light beam having an annular beam shape can be generated, thereby facilitating improved material processing.

According to some possible implementations, the optical device splits the unidirectionally rotated light beam into a first rotated light beam having a first polarization state and a second rotated light beam having a second polarization state. the unidirectionally rotated light beam and the second rotated light beam have optical powers having a first spatial rotation direction; the optical power of the first rotated light beam; a reflective element that inverts the parity of the first rotating light beam in conjunction with having a second spatial rotation direction, the second spatial rotation direction being the first spatial rotation direction. and after inversion of the parity of the first rotated light beam, the first rotated light beam and the second rotated light beam are combined to obtain the first polarization state. and a polarization coupler that generates a bidirectionally rotated light beam having a polarization state and a polarization state of the bidirectionally rotated light beam, the bidirectionally rotated light beam having an optical power having the first spatial rotation direction and the second spatial rotation state. It is characterized by having optical power having a rotational direction.

According to some possible implementations, the method splits a unidirectionally rotated light beam into a first rotated light beam having a first polarization state and a second rotated light beam having a second polarization state. the unidirectional rotating light beam and the second rotating light beam have optical powers having a first spatial rotational direction; having a second spatial rotation direction, the second spatial rotation direction being an opposite spatial rotation direction to the first spatial rotation direction; After imparting the optical power with the second spatial rotation direction, the first rotating optical beam and the second rotating optical beam are combined to obtain the first polarization state and the second polarization state. generating a bi-directionally rotating light beam having an optical power having the first direction of spatial rotation and an optical power having the second direction of spatial rotation; It is characterized by

According to some possible implementations, the system can include an optical input that receives an input rotated light beam having an optical power having a first spatial rotation direction, the input rotated light beam having a first spatial rotation direction. and a splitter for splitting into a rotating light beam and a second rotating light beam, the first rotating light beam having a first linear polarization state and the second rotating light beam having a second linear polarization state. the first rotated optical beam having an optical power having a polarization state and a first optical spatial rotation direction, wherein the first linear polarization state and the second linear polarization state are orthogonal linear polarization states; a set of reflectors that cause the optical power of the reflector to have a second spatial rotation direction, the second spatial rotation direction being an opposite spatial rotation direction to the first spatial rotation direction; and a combiner that receives the first rotated light beam and the second rotated light beam and outputs an output rotated light beam, the output rotated light beam having the first linear polarization state and The output rotating light beam has the second linear polarization state, and the output rotating light beam has an optical power in the first spatial rotation direction and an optical power in the second spatial rotation direction.

FIG. 3 is a diagram showing an example of a laser beam cutting a workpiece. FIG. 4 illustrates different cut plane interactions when performing material processing using a unidirectional rotating light beam; FIG. 2 illustrates an example embodiment of a rotating beam symmetrizer described herein that may convert a unidirectional rotating light beam to a bidirectional rotating light beam. FIG. 4 is a diagram associated with an illustration of spatial offsets between portions of a bidirectionally rotating light beam; FIG. 2 illustrates an example embodiment of a rotating beam symmetrizer described herein that may introduce a spatial offset between a first polarization state and a second polarization state in a bidirectional rotating light beam. It is. 1 is a flowchart of an example process for converting a unidirectionally rotating light beam into a bidirectionally rotating light beam as described herein.

The following detailed description of exemplary embodiments refers to the accompanying drawings. The same reference numbers may indicate the same or similar elements in different drawings.

As mentioned above, rotating light beams can be used in applications such as metal cutting, welding, and/or other types of material processing, where the beam is scanned along a surface. If a unidirectionally rotating light beam (i.e. a beam with optical power that has one principal spatial rotation direction) is used, the two directions of scanning are The laser-material interaction on opposite sides may be different. Therefore, a unidirectionally rotating light beam is transformed into a bidirectionally rotating beam that interacts with the bi-opposing law plane of the processed material (i.e., an optical power having a first spatial rotational direction and an optical power having a second (opposite) spatial rotational direction). beam rotation).

Consider the example of laser cutting, where the laser beam impinges on one surface of the workpiece and passes through the workpiece. FIG. 1A shows an example of a laser beam cutting a workpiece. In FIG. 1A, a laser beam is scanned across a workpiece (eg, by moving the laser and/or the workpiece) to create a cut in the workpiece. Here, the sides of the beam interact with the cut surface of the material being processed. If the laser beam is a unidirectionally rotating light beam, the spatial rotation can cause the two cut planes to interact differently with the laser beam in relation to the direction of scanning. FIG. 1B is a schematic diagram of the interaction of different cutting planes when material processing is performed by a unidirectional rotating light beam.

In the example shown in FIG. 1B, the laser beam is rotating clockwise and being scanned from left to right across the workpiece. For side A (the upper cut plane shown in FIG. 1B), the rotation direction and the scan direction are aligned, but for side B (the lower cut plane shown in FIG. 1B), the rotation direction and the scan direction are opposite. Therefore, the cut quality, surface finish, achievable cutting speed, etc. may be different between side A and side B, and one or the other may be more desirable. Which orientation is desirable may depend on the type of material, the thickness of the material, the power of the laser, the use of assist gas, the cutting speed, and/or one or more other factors. To improve the flexibility of material processing, it may be advantageous to maintain the desirable properties of a rotating light beam and use a laser beam that does not interact significantly differently with the material on either side of the laser beam during processing.

Some embodiments described herein convert a unidirectionally rotating light beam into a bidirectionally rotating light beam where some optical power is rotated in one direction and some optical power is rotated in the opposite direction. A rotating beam symmetrization device capable of

FIG. 2 is an illustration of an exemplary embodiment of a rotating beam symmetrizer 200 that can convert a unidirectional rotating light beam to a bidirectional rotating light beam. As shown in FIG. 2, the rotating beam symmetrizer 200 may include an optical device comprising a polarization splitter 202, a reflective element 204, a polarization combiner 206, and a polarization converter 208. Here, the unidirectionally rotated optical beam 250 may have an optical power with a spatial rotation in a first direction (e.g., the unidirectionally rotated optical beam 250 is a unidirectionally rotated optical beam with a spatial rotation in a first direction). ).

Polarization splitter 202 splits unidirectionally rotated light beam 250 into a first rotated light beam 252-1 having a first polarization state and a second rotated light beam 252-2 having a second polarization state. Contains a dividing optical element.

In some embodiments, the polarization splitter 202 is configured such that the first rotated light beam 252-1 and the second rotated light beam 252-2 have approximately equal optical power (e.g., a difference of less than 5% to 10%). The unidirectionally rotating optical beam 250 can be split approximately in half so that the optical beam 250 has a high power. Alternatively, in some implementations, the polarization splitter 202 divides the unidirectionally rotated light beam 250 such that the first rotated light beam 252-1 and the second rotated light beam 252-2 are not of approximately equal optical power. may be divided.

In some implementations, first rotating light beam 252-1 and second rotating light beam 252-2 may be linearly polarized beams (eg, having s-polarization and p-polarization). In some implementations, the first polarization state is a first linear polarization, the second polarization state is a second linear polarization, and the first linear polarization and the second linear polarization are orthogonal linear polarizations. It may be. Alternatively, in some implementations, the first polarization state is a first nonlinear polarization (e.g., circularly polarized, elliptically polarized light), the second polarization state is a second nonlinear polarization, and the first polarization state is a first nonlinear polarization. The non-linearly polarized light and the second non-linearly polarized light may be orthogonal non-linearly polarized light.

In some implementations, unidirectionally rotated light beam 250 may be unpolarized. In such a case, polarization splitter 202 can automatically generate two approximately equal portions of unidirectionally rotated light beam 250 as they pass through polarization splitter 202 . Alternatively, unidirectionally rotated light beam 250 may be polarized or partially polarized, in which case the polarization axis of unidirectionally rotated light beam 250 is aligned with polarization splitter 202 to be approximately equal. Two polarized beams of optical power can be generated. For example, if the unidirectionally rotated light beam 250 is a linearly polarized light beam, the polarization axis may be changed to produce equal powers in the first and second rotated light beams 252-1 and 252-2. It should be oriented at approximately 45 degrees to the axis of polarization splitter 202. However, any orientation angle of polarization splitter 202 may be used as long as polarization splitter 202 and polarization combiner 206 have opposite directions. In some implementations, polarization splitter 202 splits unidirectionally rotated light beam 250 such that first rotated light beam 252-1 and second rotated light beam 252-2 are not of approximately equal optical power. It may be configured as follows.

As shown in FIG. 2, polarization splitter 202 directs a first rotated light beam 252-1 (e.g., by reflection) onto a path to reflective element 204 and a second rotated light beam 252-2 (e.g., by reflection). , through transmission) to a polarization coupler 206. Here, after reflection by polarization splitter 202 and before reflection by reflective element 204, first rotated light beam 252-1 is rotated in a second spatial rotation direction (e.g., opposite to the first spatial rotation direction). , while the optical power of the second rotating light beam 252 maintains the first spatial rotation direction.

Reflective element 204 includes an optical element for inverting the parity of first rotating light beam 252-1. For example, reflective element 204 may include one reflector (eg, a high reflector (HR)) or any odd number of reflectors. As shown in FIG. 2, first rotating light beam 252-1 may be reflected by reflective element 204. Here, the first rotated light beam 252-1 may again have an optical power having a first spatial rotation direction after reflection by the reflective element 204 and before reflection by the polarization coupler 206. After reflection by polarization coupler 206, first rotated light beam 252-1 (after being combined with second rotated light beam 252-2 to form bidirectionally rotated light beam 254), as described below. can have optical power in the second spatial rotation direction. Here, an odd number of reflections (e.g., 3 reflections in this example) of the first rotating light beam 252-1 provided by the rotating beam symmetrizer 200 inverts the parity of the rotating light beam 252-1. As a result, the direction of spatial rotation of the first rotating light beam 252-1 is opposite to the direction of spatial rotation of the second rotating light beam 252-2.

In some implementations, the second rotating light beam 252-2 can be directed straight into the polarization coupler 206 (ie, without reflections), as shown in FIG. 2. Therefore, in polarization coupler 206, second rotating optical beam 252-2 may have optical power in the first spatial rotation direction. Alternatively, the second rotating light beam 252-2 may be reflected by an even number of reflectors on the optical path to the polarization coupler 206. Every reflection from the reflector causes a reversal of the parity of the reflected beam, causing a reversal of the direction of spatial rotation. Here, the optical path of the first rotating optical beam 252-1 has an odd number of parity inversions, and the optical path of the second rotating optical beam 252-2 has a zero or an even number of parity inversions, so that in the polarization coupler 206 , the first rotating light beam 252-1 and the second rotating light beam 252-2 have opposite spatial rotation directions.

Polarization coupler 206 combines first rotating light beam 252-1 and second rotating light beam 252-2 to produce bidirectionally rotating light beam 254 having a first polarization state and a second polarization state. Contains optical elements to generate. Here, the first rotating light beam 252-1 again has optical power having the second spatial rotation direction after being reflected by the polarization coupler 206 when combined with the second rotating light beam 252-2. It is possible. Since the first rotating light beam 252-1 has an optical power having a second spatial rotation direction, and the second rotating light beam 252-2 has an optical power having a first spatial rotation direction, Bidirectional rotating light beam 254 has optical power having a first spatial rotation direction and optical power having a second spatial rotation direction. In some implementations, bidirectionally rotating light beam 254 may have approximately equal optical power portions in each of the first and second spatial rotation directions, and thus may be approximately symmetrical in terms of net rotation.

In some embodiments, after combining at polarization coupler 206, bidirectionally rotated light beam 254 may have asymmetry with respect to polarization. For example, since one direction of spatial rotation of bidirectionally rotated light beam 254 is associated with one polarization and the other direction of spatial rotation of bidirectionally rotated light beam 254 is associated with another polarization, the bidirectionally rotated light beam Polarization asymmetry may exist within 254. This asymmetry can lead to differences in workpiece processing, depending for example on how the scan direction aligns with respect to the two polarizations (e.g. material absorption depends on polarization state and direction). For).

Accordingly, in some implementations, rotating beam symmetrizer 200 may include polarization converter 208. Polarization converter 208 may include, for example, a quarter wave plate. In some implementations, polarization converter 208 converts the first polarization state of bidirectionally rotating light beam 254 to a third polarization state and converts the second polarization state of bidirectionally rotating light beam 254 to a fourth polarization state. may include an optical element that converts the polarization state to that of the polarization state. In some implementations, the third polarization state and the fourth polarization state may be orthogonal polarization states that are rotationally symmetric. In some implementations, polarization converter 208 may include a set of polarization sensitive optical elements such that the third polarization state and the fourth polarization state are the final polarization states to be provided to the workpiece.

In some implementations, polarization converter 208 can be placed in the optical path of bidirectionally rotated light beam 254 after polarization combiner 206. In some implementations, polarization converter 208 can be rotated to be oriented at 45 degrees with respect to the axis of polarization combiner 206. As a result, the two linearly polarized lights emanating from the polarization coupler 206 can be converted into circularly polarized lights that are rotationally symmetric. The resulting polarization-converted bidirectionally rotating optical beam 256 therefore has perfect rotational symmetry, since it includes two rotating parts, each with its own circular polarization. That is, in some implementations, the third polarization state and the fourth polarization state are opposite circular polarizations. Other polarizations are also possible, such as elliptical polarization, which is rotationally symmetric.

In some embodiments, depending on the 45 degree orientation of polarization converter 208 (e.g., whether polarization converter 208 is oriented at +45 degrees or -45 degrees), the bidirectional rotating optical beam is polarization converted. The spatial and polarization rotation directions of the two beams making up 256 can be chosen to be aligned or opposite. For example, with one orientation of polarization converter 208, a clockwise rotating beam can have clockwise circular polarization and a counterclockwise rotating beam can have counterclockwise circular polarization. The opposite orientation of polarization converter 208 (i.e., +/-90 degree rotation of polarization converter 208) causes a clockwise rotating beam to have a counterclockwise polarization and a counterclockwise rotating beam to have a clockwise polarization. It has polarized light. These two options are referred to herein as rotation/polarization alignment or anti-alignment. Thus, in some implementations, polarization converter 208 has a first spatial rotation direction aligned with a third polarization state direction and a second spatial rotation direction aligned with a fourth polarization state direction. It can be oriented as follows. Alternatively, the polarization converter 208 may be oriented such that the first spatial rotation direction is counter-aligned with the direction of the third polarization state and the second spatial rotation direction is counter-aligned with the fourth polarization state direction. You can also do it.

Both of these options are completely symmetrical with respect to the scanning direction and can provide symmetrical machining results. However, since both rotation and polarization affect the interaction of the laser beam with the workpiece, one or the other option (rotation/polarization alignment or rotation/polarization anti-alignment) may not be suitable for the type of material being processed, e.g. , depending on the shape, laser power, etc., it may be possible to provide excellent machining results (e.g., in terms of machining speed, machining quality, etc.).

In some applications, it is desirable to change from rotation/polarization alignment to rotation/polarization anti-alignment (e.g. when changing from one material to another in the same cutting machine, or when changing from one cut or other may change dynamically during processing). Accordingly, in some embodiments, the orientation of polarization converter 208 is such that the direction of the first spatial rotation is the direction of the third polarization state and the direction of the second spatial rotation is the direction of the fourth polarization state. It may be adjustable in connection with selectively aligning or anti-aligning. If the speed is on the order of about 100 milliseconds or more, this may be accomplished by rotating polarization converter 208 by 90 degrees. Alternatively, for faster speeds, electronic drive adjustment may be used; for example, polarization converter 208 may be an electro-optic modulating wave plate.

In still other applications, it may be determined that full polarization symmetry is not required (or desired) in the polarization-converted bidirectionally rotating light beam 256. In such cases, polarization converter 208 can be adjusted to produce modified conditions other than perfect circular polarization by changing the retardance or orientation of the axes, or polarization converter 208 can be It can also be omitted (eg, to leave two orthogonal linear polarization states).

In some implementations, the rotating beam symmetrizer 200 is attached to a material processing system, e.g., a process head (e.g., an assembly directly adjacent to a workpiece), an optical delivery fiber (e.g., the input end of an optical delivery fiber), or a splice box. can be implemented in When implemented in a light delivery fiber, the light delivery fiber preferably has a round core (e.g., a circular or annular core to maintain the rotational properties of the beam) and a low birefringence or circular birefringence (e.g., a circularly polarized state). ).

The number and arrangement of elements shown in FIG. 2 is presented as an example. In practice, rotating beam symmetrizer 200 may include additional elements, fewer elements, different elements, or a different arrangement of elements than those shown in FIG. Additionally or alternatively, a set of elements (e.g., one or more elements) of rotating beam symmetrizer 200 may perform one or more of the elements described as being performed by another set of elements of rotating beam symmetrizer 200. It can also perform multiple functions.

As mentioned above, in cutting applications, there may be a preferred direction for the rotating light beam relative to the target material (eg, side A vs. side B in FIG. 1B). In such a case, the first rotated light beam 252-1 and the second rotated light beam 252-2 may be spatially offset such that the bidirectional rotated light beam 254 (or the rotating beam symmetrizer is connected to the polarization converter 208). Each side of the polarization-converted bidirectionally rotating light beam 256) can be dominated by a desired direction of rotation.

FIG. 3 includes diagrams associated with an illustration of spatial offsets between portions of bidirectional rotating light beam 254. FIG. The left diagram of FIG. 3 shows the case of a unidirectional rotating light beam 250, where side A and side B experience different rotational directions in the cutting operation, as explained above. The middle diagram of FIG. 3 shows the case where a bidirectionally rotating light beam (eg, bidirectionally rotating light beam 254 or polarization-converted bidirectionally rotating light beam 256) is provided without offset. Here, the bidirectionally rotating light beam is bidirectional and both sides of the cut can experience equal beam rotation and cutting direction. The schematic diagram on the right side of FIG. 3 shows the case where portions of the bidirectional rotating light beam 254 are spatially offset from each other. As shown in the figure, due to the spatial offset, each side can be dominated by a favorable rotation for the material. Since the optical beam has a tail (i.e. a length at which the local power decreases to zero), the offset must be large enough that the local power in the desired direction negates the local power in the tail of the undesired beam. (e.g. complete spatial separation is required).

As mentioned above, FIG. 3 is presented as an example only for illustrative purposes. Other examples may differ from those described with respect to FIG.

In some implementations, rotating beam symmetrizer 200 can include rotating optical elements to achieve a spatial offset as shown in the right diagram of FIG. FIG. 4 illustrates a spatial offset between a first polarization state and a second polarization state in a bidirectionally rotating optical beam (e.g., bidirectionally rotating optical beam 254 and polarization-converted bidirectionally rotating optical beam 256). FIG. 4 is a diagram of an exemplary embodiment of a rotating beam symmetrizer 400 that may be implemented. As shown in FIG. 4 , rotating beam symmetrizer 400 may include optical elements similar to those included in rotating beam symmetrizer 200 and may further include rotating optical elements 210 . As shown, rotating optical element 210 may be placed in the path of first rotating optical beam 252-1 between reflective element 204 and polarization coupler 206.

Rotating optical element 210 interacts with first rotating optical beam 252-1 in conjunction with creating a spatial offset between a first polarization state and a second polarization state within bidirectional rotating optical beam 254. It includes an optical element that introduces an angular shift between the second rotating light beam 252-2. For example, when implementing rotating beam symmetrizer 400 within a cutting head, rotating optical element 210 may include a rotating wedge. In some embodiments, the rotating wedge is a prism that can be mechanically rotated to introduce an angular shift between the first rotating light beam 252-1 and the second rotating light beam 252-2. It can be done. This angular shift creates a spatial offset between portions of the bidirectionally rotating light beam 254 (or polarization converted bidirectionally rotating light beam 256) on the workpiece. Rotating the rotating optical element 210 can change the direction of the spatial offset to optimize material processing conditions. Possible directions of spatial offsets include offsets between the beams in the direction perpendicular to the cutting direction (as shown in the right-hand diagram of Figure 3, for example), which offsets the orientation of the beams relative to the cutting direction, etc. It can be shifted. Such an implementation retains the possible advantages of the selection of the dominant direction relative to the cutting direction and the selection of beam rotation relative to polarization rotation, as described above.

In some implementations, the rotational orientation of rotating optical element 210 may be adjustable in conjunction with controlling spatial offset. Additionally or alternatively, the rotational orientation of rotating optical element 210 can be synchronized with the translational optics of the cutting head.

The number and arrangement of elements shown in FIG. 4 is provided as an example. In fact, rotating beam symmetrizer 400 may include additional elements, fewer elements, different elements, or a different arrangement of elements than those shown in FIG. Additionally or alternatively, a set of elements (e.g., one or more elements) of rotating beam symmetrizer 400 may be one or more described as being performed by another set of elements of symmetrizer 400. It can also perform the following functions.

FIG. 5 is a flowchart of an example process 500 for converting a unidirectionally rotating light beam 250 into a bidirectionally rotating light beam 254, as described herein.

As shown in FIG. 5, the process 500 includes splitting a unidirectionally rotated light beam into a first rotated light beam having a first polarization state and a second rotated light beam having a second polarization state. The one-way rotating light beam and the second rotating light beam have optical power in a first spatial rotation direction (block 510). For example, as described above, polarization splitter 202 splits unidirectionally rotated light beam 250 into first rotated light beam 252-1 having a first polarization state and second rotated light beam 252-1 having a second polarization state. It can be split into beams 252-2. In some implementations, unidirectionally rotated light beam 250 and second rotated light beam 252-2 have optical power in the first spatial rotation direction.

As further shown in FIG. 5, the process 500 can include directing the optical power of the first rotating light beam in a second spatial rotation direction, the second spatial rotation direction being in a first spatial rotation direction. The direction is opposite (block 520). For example, the reflective element 204 can direct the optical power of the first rotated light beam 252-1 into a second spatial rotation direction, where the second spatial rotation direction is different from the first spatial rotation direction as described above. is the opposite direction of spatial rotation.

As further shown in FIG. 5, the process 500 combines the first rotated light beam and the second rotated light beam after directing the optical power of the first rotated light beam in a second spatial rotation direction. The bidirectionally rotating light beam may include the step of generating a bidirectionally rotating light beam, wherein the bidirectionally rotating light beam has both a first polarization state and a second polarization state, and the bidirectionally rotating light beam has: having an optical power having a first spatial rotation direction and an optical power having a second spatial rotation direction (block 530). For example, as described above, the polarization coupler 206 sets the optical power of the first rotating light beam 252-1 in the second spatial rotation direction, and then converts the first rotating light beam 252-1 and the second rotating light beam 252-1 into the second spatial rotation direction. Rotating optical beams 252-2 are combined to produce bidirectional rotating optical beam 254. In some implementations, bidirectionally rotating light beam 254 has both a first polarization state and a second polarization state. In some implementations, bidirectionally rotating light beam 254 has optical power with spatial rotation in a first direction and optical power with spatial rotation in a second direction.

Process 500 may include additional embodiments, e.g., any single embodiment or multiple processes related to one or more other processes described below and/or elsewhere herein. Any combination of embodiments may be included.

In a first embodiment, process 500 converts a first polarization state of bidirectionally rotating light beam 254 to a third polarization state (e.g., by polarization converter 208) and converts a first polarization state of bidirectionally rotating light beam 254 to a third polarization state of bidirectionally rotating light beam 254. converting the second polarization state to a fourth modified state, where the third polarization state and the fourth polarization state are rotationally symmetric polarization states. In some implementations, the third polarization state and the fourth polarization state are opposite circular polarizations.

In a second embodiment, the process 500 includes aligning a first spatial rotation direction with a third polarization state direction and aligning a second spatial rotation direction with a fourth polarization state direction, or aligning a first spatial rotation direction with a fourth polarization state direction. The method may include selectively causing a direction of spatial rotation to be counter-aligned with a direction of a third polarization state and a second direction of spatial rotation being counter-aligned with a direction of a fourth polarization state.

In a third embodiment, process 500 adjusts the orientation of rotating optical element 210 in conjunction with controlling a spatial offset between a first polarization state and a second polarization state within bidirectional rotating optical beam 254. The process may include the step of:

In the fourth embodiment, the first rotating light beam 252-1 and the second rotating light beam 252-2 have approximately equal optical power.

In a fifth embodiment, the first polarization state is a first linear polarization, the second polarization state is a second linear polarization, and the first linear polarization and the second linear polarization are orthogonal linear polarizations. It is.

In a sixth embodiment, the first polarization state is a first circularly polarized light, the second polarization state is a second circularly polarized light, and the first circularly polarized light and the second circularly polarized light are orthogonal circularly polarized lights. It is.

In a seventh embodiment, polarization converter 208 includes a set of polarization sensitive optical elements such that the third polarization state and the fourth polarization state are the final polarization states delivered to the workpiece. , the third polarization state, and the fourth polarization state are rotationally symmetric orthogonal polarization states.

In an eighth embodiment, polarization converter 208 is a quarter wave plate and the third and fourth polarization states are opposite circularly polarized light.

In a ninth embodiment, the polarization converter 208 is configured such that the first spatial rotation direction is aligned with the third polarization state direction and the second spatial rotation direction is aligned with the fourth polarization state direction. Oriented.

In a tenth embodiment, the polarization converter 208 has a first spatial rotation direction anti-aligned with the direction of the third polarization state and a second spatial rotation direction anti-aligned with the fourth polarization state direction. Oriented like this.

In an eleventh embodiment, the orientation of the polarization converter 208 selectively aligns the first spatial rotation direction with the direction of the third polarization state and the second spatial rotation direction with the fourth polarization state. or adjustable in relation to anti-alignment.

In a twelfth embodiment, the rotating optical element 210 has a first polarization state associated with creating a spatial offset between a first polarization state and a second polarization state within the bidirectional rotating light beam 254. It can be used to introduce an angular shift between rotating light beam 252-1 and second rotating light beam 252-2.

In a thirteenth embodiment, the rotational orientation of rotating optical element 210 is adjustable in conjunction with controlling the spatial offset.

In a fourteenth embodiment, the rotational orientation of the rotating optical element 210 is synchronized with the translational optics of the cutting head.

In a fifteenth embodiment, the rotating beam symmetrizer 200/400 is implemented in a process head, optical delivery fiber, or splice box of a material processing system.

Although FIG. 5 shows example blocks of process 500, in some embodiments process 500 includes additional blocks, fewer blocks, different blocks, or blocks in a different arrangement than the blocks shown in FIG. may include. Additionally or alternatively, two or more of the blocks of process 500 can be executed in parallel.

Some embodiments described herein include a rotating beam symmetrizer (e.g., rotating beam symmetrizer 200, rotating beam symmetrizer 200, rotating beam symmetrizer 200, rotating beam symmetrizer 200, etc. symmetrization device 400, etc.). In this device, some optical power is rotated in one direction and some optical power is rotated in the opposite direction. As mentioned above, bidirectional rotation can be achieved by splitting the polarizations, reversing one of the split beams, and recombining the polarizations. In some implementations, the resulting linear polarization state is converted to circularly polarized light opposite to the two rotational states (e.g., to achieve perfect rotational symmetry of the spatial properties and polarization of both beams). can do.

The foregoing disclosure provides examples and descriptions and is not intended to be exhaustive or to limit embodiments to the precise forms disclosed. Various modifications and variations are possible in light of the above disclosure or may be acquired from practice of the embodiments.

Although certain combinations of features may be recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of the various embodiments. Indeed, many of these features may be combined in ways not expressly recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may be directly dependent on only one claim, the disclosure of the various embodiments also includes the combination of each dependent claim with all other claims within the scope of the claim. It includes.

Any element, act, or instruction used herein should be construed as critical or essential unless explicitly stated otherwise. Additionally, the articles "a" and "an" are intended to include one or more elements and may be used interchangeably with "one or more." Additionally, the article "the" is intended to include one or more of the elements associated with "the" and may be used interchangeably with "one or more." Furthermore, as used herein, "set" is intended to include one or more elements (e.g., related elements, unrelated elements, combinations of those elements, etc.) and is used interchangeably with "one or more". can be done. If only one element is intended, "one" or a similar word is used. Additionally, as used herein, the words "comprising,""having," and the like are intended to be open-ended terms. Further, the phrase "based on" is intended to mean "based at least in part" unless otherwise specified. Also, as used herein, "or" is intended to be inclusive when used in a series, and unless expressly stated otherwise (e.g., in combination with "any" or "only one") may be used interchangeably with "and/or".

Claims (20)

comprising a polarization splitter that splits the unidirectional rotating light beam into a first rotating light beam having a first polarization state and a second rotating light beam having a second polarization state;
The unidirectional rotating light beam and the second rotating light beam have optical powers having a first spatial rotation direction,
the first spatial rotation direction is one of clockwise or counterclockwise;
a reflective element for inverting the parity of the first rotating light beam in conjunction with imparting a second spatial rotation direction to the optical power of the first rotating light beam;
the second spatial rotation direction is the other of the clockwise or counterclockwise direction;
After reversing the parity of the first rotating light beam, combining the first rotating light beam and the second rotating light beam to have the first polarization state and the second polarization state . Equipped with a polarization coupler that produces a bidirectional rotating light beam,
The optical device , wherein the bidirectionally rotating light beam has an optical power having the first spatial rotation direction and an optical power having the second spatial rotation direction . The optical device according to claim 1 , wherein the first rotating light beam and the second rotating light beam have approximately equal optical power. the first polarization state is a first linearly polarized light, the second polarization state is a second linearly polarized light,
The optical device according to claim 1 , wherein the first linearly polarized light and the second linearly polarized light are orthogonal linearly polarized lights. the first polarization state is a first circularly polarized light, the second polarization state is a second circularly polarized light,
The optical device according to claim 1 , wherein the first circularly polarized light and the second circularly polarized light are orthogonal circularly polarized lights. a polarization converter that converts the first polarization state in the bidirectionally rotating light beam to a third polarization state and converts the second polarization state in the bidirectionally rotating light beam to a fourth polarization state; Furthermore,
the polarization converter includes a set of polarization sensitive optical elements such that the third polarization state and the fourth polarization state are final polarization states delivered to the workpiece;
The optical device according to claim 1 , wherein the third polarization state and the fourth polarization state are rotationally symmetric orthogonal polarization states. 6. The optical device of claim 5, wherein the polarization converter is a quarter wave plate and the third polarization state and the fourth polarization state are opposite circular polarizations. The polarization converter is oriented such that the first direction of spatial rotation is aligned with the direction of the third polarization state and the second direction of spatial rotation is anti-aligned with the direction of the fourth polarization state. The optical device according to claim 5. The polarization converter is oriented such that the first direction of spatial rotation is anti-aligned with the direction of the third polarization state and the second direction of spatial rotation is aligned with the direction of the fourth polarization state. The optical device according to claim 5. The orientation of the polarization converter is configured to selectively align or anti-align the first spatial rotation direction with the direction of the third polarization state and the second spatial rotation direction with the fourth polarization state. 6. Optical device according to claim 5 , which is associated adjustable. the first rotating light beam and the second rotating light beam in conjunction with creating a spatial offset between the first polarization state and the second polarization state in the bidirectional rotating light beam; 2. The optical device of claim 1 , further comprising a rotating optical element for introducing an angular shift between. 11. The optical device of claim 10 , wherein the rotational orientation of the rotating optical element is adjustable in conjunction with controlling the spatial offset. 11. Optical device according to claim 10 , wherein the rotational orientation of the rotating optical element is synchronized with the translational optics of the cutting head. The optical device includes:
process head of material processing system,
Optical delivery fiber or splice box,
2. An optical device according to claim 1, wherein the optical device is implemented in an optical device. splitting the unidirectional rotating light beam into a first rotating light beam having a first polarization state and a second rotating light beam having a second polarization state ;
The unidirectional rotating light beam and the second rotating light beam have optical powers having a first spatial rotation direction,
the first spatial rotation direction is one of clockwise or counterclockwise;
the optical power of the first rotating light beam having a second spatial rotation direction, the second spatial rotation direction being the other of the clockwise rotation and the counterclockwise rotation;
After giving the optical power of the first rotating light beam a second spatial rotation direction, the first rotating light beam and the second rotating light beam are combined to generate a bidirectional rotating light beam. including doing;
the bidirectionally rotating light beam has both the first polarization state and the second polarization state ;
The method wherein the bi-directionally rotating light beam has an optical power having the first spatial rotation direction and an optical power having the second spatial rotation direction . converting the first polarization state in the bidirectionally rotating light beam to a third polarization state ;
converting the second polarization state in the bidirectionally rotating light beam to a fourth polarization state ,
15. The method of claim 14, wherein the third polarization state and the fourth polarization state are rotationally symmetric orthogonal polarization states. 16. The method of claim 15 , wherein the third polarization state and the fourth polarization state are opposite circular polarizations. aligning the first spatial rotation direction with the direction of the third polarization state and aligning the second spatial rotation direction with the fourth polarization direction ; or 16. The method of claim 15 , further comprising selectively performing anti-aligning the second spatial rotation direction with the direction of the third polarization state and anti-aligning the second spatial rotation direction with the direction of the fourth polarization state. the method of. 15. The method of claim 14 , further comprising adjusting the orientation of a rotating optical element in conjunction with controlling a spatial offset between the first polarization state and the second polarization state in the bidirectionally rotating light beam. Method described. an optical input receiving an input rotating optical beam having an optical power in a first spatial rotational direction ;
the first spatial rotation direction is one of clockwise or counterclockwise;
a splitter for splitting the input rotating light beam into a first rotating light beam and a second rotating light beam;
the first rotating light beam has a first linear polarization state;
the second rotating light beam has a second linear polarization state and an optical power having the first spatial rotation direction ;
The first linear polarization state and the second linear polarization state are orthogonal linear polarization states,
a set of reflectors for causing the optical power of the first rotating light beam to have a second spatial rotation direction;
the second spatial rotation direction is the other of the clockwise or counterclockwise direction;
a coupler receiving the first rotating light beam and the second rotating light beam and outputting an output rotating light beam;
the output rotating light beam has the first linear polarization state and the second linear polarization state;
The system wherein the output rotating light beam has an optical power having the first spatial rotation direction and an optical power having the second spatial rotation direction . a converter for converting the first linear polarization state of the output rotating light beam to a third linear polarization state and converting the second linear polarization state of the output rotating light beam to a fourth linear polarization state; More prepared,
20. The system of claim 19 , wherein the third linear polarization state and the fourth linear polarization state are rotationally symmetric polarization states.