Improved prism

Abstract

Beam splitter arrangement (300, 400, 500, 600) comprising an optical prism (310, 410, 510, 610) having a first prism body (310a, 410a, 510a, 610a) having a first optical axis (OA31, OA41, OA51, OA61) connected to a second prism body (310b, 410b, 510b, 610b) having a second orthogonal optical axis (OA32, OA42, OA52, OA62) at a first interface (I3, I4, I5, I6) between a second face (f2) of the first prism body (310a, 410a, 510a, 610a) and a third face (f3) of the second prism body (310b, 410b, 510b, 610b) In one aspect, a first prism body (310a, 410a, 510a, 610a) includes a first face (f1) configured to receive incident light (320, 420, 520, 620), where a second prism body (310b, 410b, 510b, 610b) includes a fourth face (f4) configured to output polarized light (330, 430, 530, 630). On the other hand, the fourth face (f4) is antiparallel to the first face (f1), the fourth face (f4) is antiparallel to the first interface (I3, I4, I5, I6), and polarized light output from the fourth face (f4) of the second prism body (310b, 410b, 510b, 610b) includes one of s polarized light (S3, S4, S5, S6) and p polarized light (P3, P4, P5, P6) and extends substantially parallel to a direction (D3, D4) of the incident light (320, 420) received at the first face (f1) of the first prism body (310a, 410a).

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of optical devices. More specifically, the embodiments disclosed herein relate to optical devices implemented to improve the performance of optical systems. Background Technology

[0002] Unless otherwise stated herein, the materials described herein are not prior art to the claims of this application and are not acknowledged as prior art by virtue of their inclusion in this section.

[0003] In various fields where optical polarization devices are used to generate polarized light, for example, Wollaston prisms and walk-out crystals are conventionally used as polarization beam splitters, by which randomly polarized (unpolarized) incident light is split into linearly polarized beams.

[0004] Figure 1 is a diagram illustrating a conventional Wollaston prism polarizer. In Figure 1, the Wollaston prism polarizer 100 includes a first prism body 110 and an orthogonal prism body 120, which are fixed together at their bases along interface I1 to form two triangular prisms with perpendicular optical axes, wherein the optical axis OA11 of the first prism body 110 is orthogonal to the optical axis OA12 of the second prism body 120. Incident light IL1 is incident on the first face f1 of the first prism body 110 and penetrates to the second face f2 of the first prism body 110. At the interface I1 between the second face f2 of the first prism body 110 and the third face f3 of the second prism body 120, the incident light IL1 is decomposed (splittered) into ordinary (O) rays with S1 polarization and extraordinary (E) rays with P1 polarization. Therefore, the O-ray and E-ray bend at approximately equal angles θ1 and θ2 in opposite directions along the axis D1 of the incident light IL1 due to refraction, and diverge from the fourth surface f4 of the second prism body 120, thereby producing the S1 polarized ray and the P1 polarized ray.

[0005] Figure 2 is a diagram illustrating a conventional Lochtein prism polarizer. In Figure 2, the Lochtein prism polarizer 200 comprises a first prism body 210 and an orthogonal second prism body 220, which are fixed together at their bases along interface I2 to form two triangular prisms with perpendicular optical axes. The optical axis OA21 of the first prism body 210 is orthogonal to the optical axis OA22 of the second prism body 220, however, they are orthogonal on different axes compared to the Wollaston prism polarizer in Figure 1. Incident light IL2 is incident on the first face f1 of the first prism body 210 and passes through to the second face f2 of the second prism body 210. Upon exiting from the second face f2 of the second prism body 210, the incident light IL2 is decomposed (segmented) at interface I2 between the second face f2 of the first prism body 210 and the third face f3 of the second prism body 220 into ordinary (O) rays with S2 polarization and extraordinary (E) rays with P2 polarization. Therefore, depending on the angle of interface I2, the O and E rays bend approximately at an angle θ3 along the axis D2 of the incident light IL2 due to refraction. When exiting from the fourth face f4 of the second prism 220, the O and E rays diverge further, thus producing S2-polarized and P2-polarized rays.

[0006] Figure 7 is a diagram illustrating a conventional walk-off crystal. In Figure 7, the walk-off crystal 700 comprises a crystal 710 with birefringent properties. When the direction D7 of the incident light IL7 is not 0 degrees or 90 degrees relative to the optical axis OA7 of the crystal 710 positioned at an angle α7, the incident light IL7 splits into a first beam B1 and a second beam B2 at the first surface f1 of the crystal 710. The first beam B1 travels through the crystal 710 along the length L of the crystal 710 in the direction D7 of the incident light IL7, and the second beam B2 travels through the crystal 710 along a direction D7' offset from the direction D7 by an offset angle θ7. The first beam B1 exits from the second surface f2 of the crystal 710 along the direction D7, and the second beam B2 exits from the second surface f2 of the crystal 710 along a direction D7' that is substantially parallel to the direction D7 and offset from the direction D7 by a walk-off distance d7. According to the following equation (1), the walk-off distance d7 is related to the length L of the crystal 710, therefore:

[0007] d7 = L tan θ7 (1).

[0008] Therefore, in order to increase the walk-off distance d7, the length L of the crystal 710 must be increased accordingly, which complicates the expectation of reducing the overall size of the optical device implementing the walk-off crystal 710.

[0009] Walk-off crystals (walk-off crystal 700 as depicted in Figure 7) are commonly implemented as isolators in fiber optic communication and laser systems to reduce or eliminate the effects of optical feedback and the laser's own energy reflection back to itself. For example, feedback can destabilize the light source due to amplitude fluctuations, frequency shifts, mode jumps, noise, and even damage.

[0010] The subject matter claimed herein is not limited to embodiments that address any shortcomings or operate only in environments such as those described above. Rather, this background is provided merely to illustrate an example technical field in which some of the embodiments described herein can be practiced.

[0011] These and other advantages of the present invention will become more fully apparent from the following detailed description of the invention. Summary of the Invention

[0012] This summary is provided to introduce, in a simplified form, the concept choices further described in the detailed description below. This summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0013] This document discloses a beam splitter device. In one aspect of this disclosure, a beam splitter device includes an optical prism having a first prism body having a first optical axis, the first prism body being connected to a second prism body at a first interface between a second facet of the first prism body and a third facet of a second prism body having a second orthogonal optical axis. In one aspect of this disclosure, the first prism body includes a first facet configured to receive incident light, wherein the second prism body includes a fourth facet configured to output polarized light. In another aspect of this disclosure, the fourth facet is antiparallel to the first facet. In another aspect of this disclosure, the fourth facet is antiparallel to the first interface. In another aspect of this disclosure, the polarized light output from the fourth facet of the second prism body includes one of s-polarized light and p-polarized light. In yet another aspect of this disclosure, the s-polarized light and p-polarized light extend substantially parallel to the direction of the incident light received at the first facet of the first prism body.

[0014] This document discloses a beam splitter device in which a second prism body includes a fifth facet adjacent to the fourth facet and adapted to output the other of the s-polarized light and the p-polarized light. In one aspect of this disclosure, the beam splitter device includes a Glan-Taylor prism and a third prism body, the Glan-Taylor prism having a second prism body of the optical prism, and the third prism body having a third optical axis parallel to a second optical axis. In another aspect of this disclosure, the third prism body of the Glan-Taylor prism has a sixth facet and a seventh facet opposite to the sixth facet, the sixth facet being spaced apart from the fourth facet of the second prism body by an air gap. In yet another aspect of this disclosure, the sixth facet of the Glan-Taylor prism is configured to receive the one of the s-polarized light and the p-polarized light. In one aspect of this disclosure, the seventh facet of the Glan-Taylor prism is configured to output the one of the s-polarized light and the p-polarized light received at the sixth facet of the Glan-Taylor prism. In one aspect of this disclosure, the seventh facet of the Glan-Taylor prism has one of the following: (i) parallel to the first facet of the first prism body; and (ii) antiparallel to the first facet of the first prism body. In another aspect of this disclosure, the sixth facet of the Glan-Taylor prism has one of the following: (i) antiparallel to the first interface; and (ii) parallel to the fourth facet of the second prism body. In another aspect of this disclosure, the sixth facet of the Glan-Taylor prism is antiparallel to the seventh facet of the Glan-Taylor prism. In one aspect of this disclosure, the optical prism includes a Wollaston prism.

[0015] This document discloses a laser system, which includes a laser device and a beam splitter device, wherein incident light to the beam splitter device is generated by the laser device.

[0016] This document discloses a beam splitter system. In one aspect of this disclosure, the disclosed beam splitter system includes a first rhombic prism block having a first and a second face, and a third and a fourth face, which are relatively parallel, wherein the first and second faces are positioned between the third and fourth faces, and the first prism has a fifth face, which is spaced apart from the first face of the first rhombic prism block by an air gap, wherein incident light received by the third face of the first rhombic prism block is output as first polarized light at the first face of the first rhombic prism block, and wherein the incident light received by the third face of the first rhombic prism block is reflected at the first face of the first rhombic prism block, passes through the first rhombic prism block toward the second face of the first rhombic prism block, is reflected at the second face of the first rhombic prism block, and is output as second polarized light at the fourth face of the first rhombic prism block. In one aspect of this disclosure, the beam splitter system may include a first rhombic prism block having a first optical axis and a first prism having a second optical axis, wherein one of the following conditions is met: (i) the first optical axis and the second optical axis are parallel; and (ii) the first optical axis and the second optical axis are orthogonal. In one aspect of this disclosure, the first optical axis extends along a direction between a first facet of the first rhombic prism block and a second facet of the first rhombic prism block. In another aspect of this disclosure, the second optical axis extends along a direction parallel to a sixth facet of the first prism. In another aspect of this disclosure, first polarized light output at the first facet of the first rhombic prism block is received by the fifth facet of the first prism and output at the sixth facet of the first prism.

[0017] Further features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practice of the invention. The features and advantages of the invention can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the invention will become more apparent from the following description and the appended claims, or may be learned by practice of the invention as set forth below. Attached Figure Description

[0018] To further illustrate the above and other advantages and features of the present invention, the invention will be described in more detail with reference to specific embodiments shown in the accompanying drawings. It should be understood that these drawings depict only exemplary embodiments of the invention and are therefore not intended to limit its scope. The invention will be described and explained with additional features and details using the accompanying drawings, in which:

[0019] Figure 1 is a diagram showing a conventional Wollaston prism polarizer;

[0020] Figure 2 is a diagram showing a conventional Lochon prism polarizer;

[0021] Figure 3 It is an exemplary polarizing prism according to this disclosure;

[0022] Figure 4 This is another exemplary polarizing prism system according to this disclosure;

[0023] Figure 5 This is another exemplary polarizing prism system according to this disclosure;

[0024] Figure 6 This is another exemplary polarizing prism system according to this disclosure;

[0025] Figure 7 is a diagram of a typical crystal walk-out process;

[0026] Figure 8 This is an exemplary walk-away prism system according to this disclosure; and

[0027] Figure 9 This is another exemplary walk-away prism system according to this disclosure. Detailed Implementation

[0028] It should be understood that the accompanying drawings and descriptions of this invention may have been simplified to illustrate elements relevant to a clear understanding of the embodiments of the invention, while other elements found in laser devices or systems for operating laser devices have been omitted for clarity. Those skilled in the art will recognize that other elements may be desirable and / or required for implementing the embodiments of the invention. However, because such elements are well known in the art and because they are not conducive to a better understanding of the embodiments of the invention, a discussion of such elements is not provided herein. It should also be understood that the accompanying drawings included herein provide only a illustrative representation of the currently preferred structure of the invention, and structures falling within the scope of the embodiments of the invention may include structures different from those shown in the drawings. Reference will now be made to the drawings, in which the same structures are provided with the same reference numerals.

[0029] As discussed above, the Wollaston prism polarizer of Figure 1 produces S1-polarized and P1-polarized rays. However, since both the S1-polarized and P1-polarized rays diverge from the axis D1 of the incident light IL1 by angles θ1 and θ2, which can be relatively large, sometimes ranging from 15 to 45 degrees, this can be disadvantageous considering the specific application in which the Wollaston prism polarizer 100 will be implemented. Therefore, the disclosed embodiments are advantageous because, in some instances, they can produce one of the S1-polarized and P1-polarized rays having a direction substantially parallel to the axis D of the incident light IL. Additionally, the Wollaston prism polarizer 100 is limited in terms of its numerical aperture range. Furthermore, the disclosed embodiments advantageously produce both S1-polarized and P1-polarized rays within a specific wavelength range.

[0030] A solution for generating either an S1-polarized ray or a P1-polarized ray having a direction substantially parallel to the axis D1 of the incident light IL1, and for providing an operable range of numerical apertures, may include implementing a Lochtein prism polarizer instead of a Wollaston prism polarizer. Such an example Lochtein prism has been discussed above with respect to the prism of Figure 2.

[0031] However, although the P2-polarized ray exits from the fourth surface f4 of the second prism 220 along a direction parallel to the axis D2 of the incident light IL2, the direction of the P2-polarized ray is independent of its wavelength. Therefore, the exemplary embodiments disclosed herein implement a polarization device in which polarized light within a specific wavelength range is emitted along a direction substantially parallel to the incident light.

[0032] Furthermore, while some prior art crystal arrangements can be formed to produce substantially parallel polarized beams, such as the walk-off crystal described in Figure 7, the manufacturing cost associated with walk-off crystals is high, and the implementation is limited to short-pass length systems due to their size, and heat dissipation is problematic in high-power applications. Additionally, while polarization beam splitters (PBSs) can be implemented as an alternative to walk-off crystals due to their lower manufacturing cost and relatively small size, PBSs have a polarization extinction ratio (PER), a measure of the degree to which light is confined in the dominant linear polarization mode, which is unsatisfactory for high-power isolator applications. Therefore, the disclosed embodiments herein improve upon each of these arrangements and also provide additional vertical and angled configurations.

[0033] As previously noted, existing polarization devices are limited by their ability to emit polarized light in a specific wavelength range along a direction substantially parallel to the incident light, or have other drawbacks related to their size or loss, or lack additional flexibility regarding the direction and polarization of the light output. Generally, it is desirable that polarization devices, and the examples described herein, can be implemented in a compact design and produce polarized light in several configurations within a wavelength range.

[0034] Figure 3 This is an exemplary polarizing prism system according to one example of the present disclosure. While the spectrum of the prism system disclosed in this and other embodiments is determined by the material of the polarizing prism, the disclosed prism system has particular advantages in the context of optical communications, typically used at wavelengths within the applicable infrared range. For example, prism materials may include calcite, MgF2, quartz, α-BBO, and / or YVO4. For instance, quartz prism materials can be used for wavelengths from about 400 nm to about 2.0 μm, magnesium fluoride prism materials can be used for wavelengths from about 200 nm to about 6.0 μm, α-BBO prism materials can be used for wavelengths from about 190 nm to about 3.5 μm, calcite prism materials can be used for wavelengths from about 350 nm to about 2.3 μm, and YVO4 (yttrium orthovanadate) prism materials can be used for wavelengths from about 900 nm to about 3.4 μm. Figure 3 In this application, a polarizing prism system 300 includes a polarizing prism 310, which comprises a first prism body 310a and a second prism body 310b. The first prism body 310a has a first optical axis OA31 (depicted as a double-headed arrow) extending along a direction vertical to the plane of the paper (in the same plane as the paper) and substantially parallel to a first face f1 of the first prism body 310a. The second prism body 310b has a second optical axis OA32 (depicted with dots), extending along a direction entering / leaving the plane of the paper and substantially antiparallel (perpendicular) to the first optical axis OA31. This notation convention for representing optical axes will be used throughout this application. The first prism body 310a and the second prism body 310b are joined together at an interface I3 between a second face f2 of the first prism body 310a and a third face f3 of the second prism body 310b. In some embodiments, the second surface f2 of the first prism 310a and the third surface f3 of the second prism 310b can be bonded together using an optically transparent adhesive (for the operating wavelength of the incident light) or an optical contact bond. In an optical contact bond, flat and clean optical surfaces are brought into close contact to form a solid bond, for example, through intermolecular forces such as van der Waals forces and hydrogen bonds.

[0035] like Figure 3As depicted, the fourth facet f4 of the second prism 310b is offset by an offset angle δ3 from the first facet f1 of the first prism 310a. Therefore, the fourth facet f4 of the second prism 310b is antiparallel to the first facet f1 and the second facet f2 of the first prism 310a, as well as the third facet f3 of the second prism 310b, because the refractive index of 310a / 310b differs from the refractive index of the surrounding medium (e.g., air). Furthermore, the third facet f3 of the second prism 310b and the fourth facet f4 of the second prism 310b are antiparallel.

[0036] exist Figure 3 In this process, light 320 is incident on the first surface f1 of the first prism 310a. Here, light 320 can be provided by a light generation system (such as a laser system L3) and / or delivered via a waveguide (such as an optical fiber), as unpolarized or randomly polarized light, which is depicted as having mixed polarization by the point (ordinary ray) and line (extraordinary ray) symbols of its mixing in light 320. The first surface f1 of the first prism 310a receives light 320 along direction D3, which forms a normal incidence (approximately 90 degrees) on surface f1. Light 320 passes through the first prism 310a and reaches the second surface f2 of the first prism 310a. At interface I3, light 320 is split into a first beam B31 and a second beam B32. Since the incident light is unpolarized (the incident light contains polarization components parallel and perpendicular to the plane of the paper), the polarization directions of the two beam components are perpendicular and parallel to the optical axis OA32, and therefore have different refractive indices in B32. This creates different angles of refraction at interface I3 and separates them in space. The first beam B31 travels through the second prism 310b and exits from the fourth face f4 of the second prism 310b as the exiting first beam B31', wherein the direction D3' of the first beam B31' exiting from the fourth face f4 is deflected to be substantially parallel to the direction D3 of the incident light 320 due to the angle δ3 of the fourth face f4 of the second prism 310b. That is, the angle δ3 and the angle of interface I3 (faces f2 / f3) are relatively configured such that the direction D3' of the exiting first beam B31' is substantially parallel to direction D3. This can be adjusted according to a specific target wavelength or the material used. The second beam B32 also travels through the second prism 310b and exits from the fourth face f4 of the second prism 310b as the exiting second beam B32'. The exiting second beam forms an angle θ3 with the exiting first beam B31' in the direction D3”, which is also determined by the angle δ3 of the fourth face f4 of the second prism 310b. Here, the exiting first beam B31' and the exiting second beam B32' can be considered together as the output polarized beam 330, but each has a different polarization.

[0037] exist Figure 3In this process, an offset angle δ3 can be selected to adjust the directions D3' and D3'" of the emitted first beam B31' and the emitted second beam B32' relative to the direction D3 of the incident light 320, and to adjust between the directions D3' and D3'" of the emitted first beam B31' and the emitted second beam B32'. In some embodiments, it may be desirable to select an offset angle δ3 to provide one or more of these adjustments.

[0038] exist Figure 3 In this context, the outgoing beam B31' can be considered as S-polarized light S3, and the outgoing beam B32' can be considered as P-polarized light P3. Here, S-polarized light S3 can be considered as an ordinary ray, and P-polarized light P3 can be considered as an extraordinary ray.

[0039] Figure 4 This is another exemplary polarizing prism system according to examples of this disclosure. As will be understood, regarding Figure 3 The concepts and explanations also apply to Figure 4 The functionality of the other embodiments is described, but additional descriptions are provided for each. Additionally, Figure 4 The polarizing prism system is similar to Figure 3 The polarizing prism system, except that the tilt direction of I4 is different and the angle δ4 has been adjusted so that another polarized beam (i.e., the extra ray (as shown in the figure)) is parallel to the incident beam 420. In other words, the angles I4 and δ4 are chosen to determine which output beam is parallel and which is not. Figure 4 In this embodiment, the polarizing prism system 400 includes a polarizing prism 410, which comprises a first prism body 410a and a second prism body 410b. The first prism body 410a has a first optical axis OA41 (shown as a double-headed arrow) extending in a direction vertical relative to the paper surface and substantially parallel to a first face f1 of the first prism body 410a, and the second prism body 410b has a second optical axis OA42 (shown as a dot) extending in a direction entering / leaving the paper surface and substantially antiparallel to the first optical axis OA41. Specifically, the first optical axis OA41 and the second optical axis OA42 can be considered orthogonal. The first prism body 410a and the second prism body 410b are joined together along an interface I4 between the second face f2 of the first prism body 410a and the third face f3 of the second prism body 410b. In some embodiments, an optically transparent adhesive can be used to bond the second face f2 of the first prism body 410a and the third face f3 of the second prism body 410b together.

[0040] like Figure 4As depicted, the fourth face f4 of the second prism 410b is offset by an offset angle δ4 relative to the first face f1 of the first prism 410a. Therefore, the fourth face f4 of the second prism 410b is substantially antiparallel to the first face f1 and the second face f2 of the first prism 410a, and to the third face f3 of the second prism 410b. Furthermore, the third face f3 of the second prism 410b and the fourth face f4 of the second prism 410b are substantially antiparallel to each other. Figure 4 (Not drawn to scale) because the refractive index of 410a / 410b is different from that of the surrounding medium (e.g., air). That is, the degree of antiparallelism between the third face f3 and the fourth face f4 of the second prism 410b can be adjusted to make D4 and D4” parallel.

[0041] exist Figure 4 In this process, light 420 is incident on the first surface f1 of the first prism 410a. Here, the light 420 can be provided by a light generation system (such as a laser system L4) and / or delivered via a waveguide (such as an optical fiber), as unpolarized or randomly polarized light. When the first surface f1 of the first prism 410a receives light 420 along direction D4, the light 420 passes through the first prism 410a and reaches the second surface f2 of the first prism 410a, where it is split into a first beam B41 and a second beam B42 at interface I4. The first beam B41 travels through the second prism 410b and exits from the fourth surface f4 of the second prism 410b as an exiting first beam B41', wherein the direction D4' of the exiting first beam B41' is substantially antiparallel to the direction D4 of the incident light 420. The second beam B42 also travels through the second prism 410b and exits from the fourth f4 of the second prism 410b as the exiting second beam B42', which forms an angle θ4 with the exiting first beam B41' in the direction D4”, the direction being substantially parallel to the direction D4. Here, the exiting first beam B41' and the exiting second beam B42' can be collectively regarded as the output polarized beam 430.

[0042] exist Figure 4 In this configuration, an offset angle δ4 can be selected to adjust the directions D4' of the emitted first beam B41' and D4'' of the emitted second beam B42' relative to the direction D4 of the incident light 420, as well as the adjustment between the directions D4' and D4' of the emitted first beam B41' and the second beam B41'. In some embodiments, it may be desirable to select the offset angle δ4 to provide one or more of these adjustments. In this respect, the polarizing prism system 400 is similar to Figure 3 The polarizing prism system 300, except that the angle δ4 and the angles of the interfaces I4 (f2 and f3) are selected such that the second beam B42' is substantially parallel to the direction D4.

[0043] exist Figure 4 In this context, the outgoing beam B41' can be considered as S-polarized light S4, and the outgoing beam B42' can be considered as P-polarized light P4. Here, S-polarized light S4 can be considered as an ordinary ray, and P-polarized light P4 can be considered as an extraordinary ray.

[0044] Figure 5 This is another exemplary polarizing prism system according to this disclosure. As will be understood, regarding Figure 3-4 The concepts and explanations also apply to Figure 5 The functionality of the other embodiments is described herein, but additional descriptions are provided for each. Figure 5 In this embodiment, the polarizing prism system 500 includes a first polarizing prism 510 and a second polarizing prism 540, wherein the second polarizing prism 540 can be considered as a Glan-Taylor prism configuration. The first polarizing prism 510 includes a first prism body 510a and a second prism body 510b. The first prism body has a first optical axis OA51 (depicted as a point) extending along a direction entering / leaving the paper, and the second prism body 510b has a second optical axis OA52 (depicted as a double-headed arrow) extending along a direction vertical relative to the paper and substantially antiparallel to the first optical axis OA51. The first prism body 510a and the second prism body 510b are joined together at an interface I5 between a second facet f2 of the first prism body 510a and a third facet f3 of the second prism body 510b. In some embodiments, an optically transparent adhesive can be used to bond the second facet f2 of the first prism body 510a and the third facet f3 of the second prism body 510b together.

[0045] like Figure 5 As depicted, the fourth facet f4 of the second prism 510b is offset by an offset angle δ5 from the first facet f1 of the first prism 510a. Therefore, the fourth facet f4 of the second prism 510b is antiparallel to the first facet f1 and the second facet f2 of the first prism 510a, as well as the third facet f3 of the second prism 510b. Furthermore, the third facet f3 of the second prism 510b is antiparallel to the fourth facet f4 of the second prism 510b. In addition, the second prism 510b includes a fifth facet f5, which is described below.

[0046] exist Figure 5In this design, the second polarizing prism 540 includes a second prism body 510b and a third prism body 540a of the first polarizing prism 510. The third prism body has a third optical axis OA53 (depicted as a double-headed arrow) extending vertically relative to the plane of the paper and substantially parallel to the second optical axis OA52 and substantially antiparallel to the first optical axis OA51. Specifically, the third optical axis OA53 is considered orthogonal to the first optical axis OA51. The third prism body 540a is spaced apart from the second prism body 510b of the first polarizing prism 510 by a gap, which can be an air gap AG5. It should be noted that other materials with different refractive indices can also be used; however, air is an inexpensive and useful medium for high-power applications. In one example, the air gap AG5 (and other air gaps discussed herein) can be of any size to achieve the desired angle and spacing of the output beam. However, the air gap AG5 should be significantly larger than the operating wavelength of the incident light to avoid energy leakage of the beam B51. For example, due to the exponential decay of the evanescent wave amplitude, its amplitude becomes very weak at a distance of several wavelengths, so an air gap of 5 times or more of the incident wavelength is sufficient to prevent energy leakage while maintaining other advantageous properties.

[0047] like Figure 5 As depicted, the sixth facet f6 of the third prism 540a is substantially parallel to the fourth facet f4 of the second prism 510b. Therefore, similar to the fourth facet f4 of the second prism 510b, the sixth facet f6 of the third prism 540a is offset from the first facet f1 of the first prism 510a by an offset angle δ5. Furthermore, the sixth facet f6 of the third prism 540a is substantially parallel to the first facet f1 and the second facet f2 of the first prism 510a in the opposite direction, and the first facet f1 of the first prism 510a is substantially parallel to the seventh facet f7 of the third prism 540a.

[0048] exist Figure 5In this process, light 520 is incident on the first surface f1 of the first prism 510a. Here, the light 520 can be provided by a light generation system (such as a laser system L5) and / or delivered via a waveguide (such as an optical fiber), as unpolarized or randomly polarized light. The first surface f1 of the first prism 510a receives the light 520 along the direction D5, and the light 520 passes through the first prism 510a to reach the second surface f2 of the first prism 510a and is split at the interface I5 into a first polarized beam B51 and a second polarized beam B52 with different directions and polarizations. The first polarized beam B51 travels through the second prism body 510b and is reflected at the fourth face f4 of the second prism body 510b (because the final incident angle of beam B51 satisfies the total internal reflection condition on face f4). It is then guided to the fifth face f5 of the second prism body 510b and passes through the fifth face f5 of the second prism body 510b as an outgoing first polarized beam B51' along the direction D5' which is substantially perpendicular to the incident light 520.

[0049] exist Figure 5 In the process, the second polarized beam B52 passes through the second prism 510b (because the final incident angle of beam B52 does not satisfy the total internal reflection condition on surface f4) and passes through the fourth surface f4 of the second prism 510b as the outgoing second polarized beam B52'. Then, the outgoing second polarized beam B52' passes through the air gap AG5 and enters the sixth surface f6 of the third prism 540a, passes through the third prism 540a, and passes through the seventh surface f7 of the third prism 540a as the outgoing second polarized beam B52" along the direction D5". Here, the direction D5" of the outgoing second polarized beam B52" is offset from the direction D5 by an offset angle θ5.

[0050] exist Figure 5 In this context, the outgoing beam B51' can be considered as S-polarized light S5, and the outgoing beam B52” can be considered as P-polarized light P5. Here, S-polarized light S3 can be considered as ordinary light, and P-polarized light P3 can be considered as extraordinary light.

[0051] Figure 6 This is another exemplary polarizing prism system according to this disclosure. As will be understood, regarding Figure 3-5 The concepts and explanations also apply to Figure 6 The functionality of the other embodiments is described herein, but additional descriptions are provided for each. Figure 6 In the middle, although the polarizing prism system 600 includes similar components as described above... Figure 5The features discussed are those of a first polarizing prism 610 and a second polarizing prism 640. However, the third prism body 640a includes a seventh face f7 that is antiparallel to the first face f1 of the first prism body 610a. Specifically, the seventh face f7 of the third prism body 640a is offset from the first face f1 of the first prism body 610a by an offset angle δ62 to allow selection or configuration of the exit angle of the beam B62”.

[0052] exist Figure 6 In this embodiment, the polarizing prism system 600 includes a first polarizing prism 610 and a second polarizing prism 640 having a Glan-Taylor prism configuration. The first polarizing prism 610 includes a first prism body 610a and a second prism body 610b. The first prism body has a first optical axis OA61 (depicted as a point) extending along a direction entering / leaving the paper, and the second prism body has a second optical axis OA62 (depicted as a double-headed arrow) extending along a direction vertical relative to the paper and substantially antiparallel to the first optical axis OA61. Specifically, the first optical axis OA61 and the second optical axis OA62 are substantially orthogonal. The first prism body 610a and the second prism body 610b are joined together along an interface I6 between a second facet f2 of the first prism body 610a and a third facet f3 of the second prism body 610b. In some embodiments, an optically transparent adhesive can be used to bond the second facet f2 of the first prism body 610a and the third facet f3 of the second prism body 610b together.

[0053] like Figure 6 As depicted, the fourth facet f4 of the second prism 610b is offset by an offset angle δ61 from the first facet f1 of the first prism 610a. Therefore, the fourth facet f4 of the first prism 610a is substantially antiparallel to the first facet f1 and the second facet f2 of the first prism 610a, and to the third facet f3 of the second prism 610b. Furthermore, the third facet f3 of the second prism 610b and the fourth facet f4 of the second prism 610b are substantially antiparallel. In addition, the second prism 610b includes a fifth facet f5, which is described below.

[0054] exist Figure 6 In the first polarizing prism 610, the second polarizing prism 640 includes a second prism body 610b and a third prism body 640a. The third prism body has a third optical axis OA63 (depicted as a double-headed arrow) extending in a direction vertical relative to the plane of the paper and substantially parallel to the second optical axis OA62 and substantially antiparallel to the first optical axis OA61. The third prism body 640a is spaced apart from the second prism body 610b of the first polarizing prism 610 by an air gap AG6.

[0055] like Figure 6As depicted, the sixth facet f6 of the third prism 640a is substantially parallel to the fourth facet f4 of the second prism 610b. Therefore, like the fourth facet f4 of the second prism 610b, the sixth facet f6 of the third prism 640a is offset from the first facet f1 of the first prism 610a by an offset angle δ61. Similarly, the sixth facet f6 of the third prism 640a is substantially parallel to the first facet f1 and the second facet f2 of the first prism 610a, and the first facet f1 of the first prism 610a is substantially parallel to the seventh facet f7 of the third prism 640a.

[0056] exist Figure 6 In this process, light 620 is incident on the first surface f1 of the first prism 610a. Here, the light 620 can be provided by a light generation system (such as a laser system L6) and / or delivered via a waveguide (such as an optical fiber), as unpolarized or randomly polarized light. The first surface f1 of the first prism 610a receives the light 620 along direction D6. The light 620 then passes through the first prism 610a and reaches the second surface f2 of the first prism 610a, where it is split into a first polarized beam B61 and a second polarized beam B62 at interface I6. The first polarized beam B61 travels through the second prism 610b, is reflected at the fourth surface f4 of the second prism 610b, is guided to the fifth surface f5 of the second prism 610b, and passes through the fifth surface f5 of the second prism 610b as an outgoing first polarized beam B61' along direction D6', which is substantially perpendicular to the direction D6 of the incident light 620.

[0057] exist Figure 6 In the process, the second polarized beam B62 passes through the second prism 610b and its fourth surface f4 as the outgoing second polarized beam B62'. Then, the outgoing second polarized beam B62' passes through the air gap AG6 and enters the sixth surface f6 of the third prism 640a. Next, the outgoing second polarized beam B62' passes through the third prism 640a and its seventh surface f7 as the outgoing second polarized beam B62" along the direction D6". Here, the direction D6" of the outgoing second polarized beam B62" is substantially parallel to the direction D6 of the incident light 620 and is spaced apart from the direction D6 of the incident light 620 by a distance d63.

[0058] exist Figure 6In this context, the outgoing beam B61' can be considered as S-polarized light S6, and the outgoing beam B62" can be considered as P-polarized light P6. Here, S-polarized light S6 can be considered as an ordinary ray, and P-polarized light P6 can be considered as an extraordinary ray. Furthermore, the distance d63 can also be determined based on a combination of the offset angles δ61 and δ62 and the lateral distance length (in the D6 direction) of the third prism 640a; that is, the size of the third prism 640a can be selected to obtain the desired distance d63.

[0059] Figure 8 This is an exemplary walk-away prism system according to this disclosure. As will be understood, regarding Figure 3-6 The concepts and explanations also apply to Figure 8 The functionality of the other embodiments is described herein, but additional descriptions are provided for each. Figure 8 In this embodiment, the walk-off prism system 800 includes a first prism block 810 and a prism body 830. The first prism block has a rhomboid shape (e.g., as shown in the plane of the paper, having an acute angle between faces f3 and f1 and an obtuse angle between faces f3 and f2), and the prism body has a polygonal shape, shown as a trapezoidal shape. Here, the prism body 830 may have other geometric shapes, such as a triangular shape. The first prism block 810 includes relatively parallel first faces f1 and f2, and relatively parallel third faces f3 and f4, wherein the first faces f1 and f2 are positioned between the third faces f3 and f4. It should be noted that the first faces f1 and f2 are parallel to provide parallel outgoing beams S8 and P8; however, if parallelism of S8 and P8 is not desired, the first faces f1 and f2 may be deviated from parallel, and the tilt angle of face f2 may be customized to obtain a specific desired angle between beams S8 and P8. The first prism block 810 has a first optical axis OA81 (depicted as a double-headed arrow) extending in a direction vertical relative to the plane of the paper. The first optical axis OA81 extends between the first facet f1 and the second facet f2 of the first prism block 810 and is parallel to the first facet f1 and the fourth facet f4 of the first prism block 810. The prism body 830 has a second optical axis OA82 (depicted as a double-headed arrow) extending in a direction vertical relative to the plane of the paper and is substantially parallel to the sixth facet f6 of the prism body 830. The first optical axis OA81 and the second optical axis OA82 can be considered to be substantially parallel. The prism body 830 includes a fifth facet f5, which is spaced apart from the first facet f1 of the first prism block 810 by an air gap AG8. Therefore, the first facet f1 and the second facet f2 of the first prism block 810 are substantially parallel to the fifth facet f5 of the prism body 830.

[0060] exist Figure 8In this process, light 820 is incident on the first face f1 of the first prism block 810. Here, light 820 can be provided by a light generation system (such as a laser system L8) and / or delivered via a waveguide (such as an optical fiber), as unpolarized or randomly polarized light. The first face f3 of the first prism block 810 receives light 820 along direction D8, and light 820 passes through the first prism block 810 to reach the first face f1 of the first prism block 810. Light 820 is split into a first polarized beam B81 and a second polarized beam B82 at the first face f1 of the first prism block 810. The first polarized beam B81 is reflected at the first face f1 of the first prism block 810 toward the second face f2 of the first prism block 810, and at the second face f2 of the first prism block 810 toward the fourth face f2 of the first prism block 810, and passes through the fourth face f2 of the first prism block 810 as S-polarized light S8 along direction D8', which is substantially parallel to direction D8.

[0061] The second polarized beam B82 passes through the first face f1 of the first prism block 810, through the air gap AG8, and enters the fifth face f5 of the prism body 830. It should be noted that, although not exaggerated in the accompanying drawings, when the beam exits from the first face f1, the beam B82 is slightly angled, and then when it passes through the fifth face f5 of the prism body 830, the beam returns at an angle to be parallel to the incident light 820, thus creating a deflection between the incident light 820 and the light P8. This increases the total distance d8, where the additional deflection is determined based on the travel distance of the beam B81 to face f2. Therefore, the size of the distance d8 can be adjusted based on the size of the air gap AG8, where a larger air gap AG8 will produce a larger distance d8. Alternatively, the distance d8 can also be changed based on the size of the prism block 810 on the optical axis OA81. The second polarized beam B82 then passes through the prism body 830 and is output as a P-polarized light P8 along the direction D8 at the sixth face of the prism body 830. Here, the distance between P-polarized light P8 and S-polarized light S8 is d8.

[0062] Figure 9 This is another exemplary walk-away prism system according to this disclosure. As will be understood, regarding Figure 3-6 The concept and explanation of 8 also apply to Figure 9 The functions of the other embodiments are described, but additional descriptions are provided for each. Specifically, in addition to the optical axes OA91 and OA92 of the walk-off prism system 900 being related to optical axes OA81 and OA82 (…), the functions of the walk-off prism system 900 are described. Figure 8 Orthogonal, such that the other polarities of the output beams S9 and P9 are the same as those of the output beams P9 and P9. Figure 8 In addition to the polarity being changed, the walk-off prism system 900 and Figure 8 The walk-off prism system is the same.

[0063] For conventional polarizing beam splitters in existing technology, the prism material is usually ordinary glass, and multiple layers of dielectric films are coated between the prisms to achieve polarization beam splitting. Although Figure 8 and Figure 9 The embodiment may share some similarities with the Gran-Foco prism, but this structure includes a more advantageous prism bevel, which allows two differently polarized lights to be emitted in the same direction. As described above, Figure 8 Implementation examples and Figure 9 The difference between the embodiments lies in the optical axis direction of the prism block. As shown in the figure, the polarization component with the same direction as the crystal axis is transmitted.

[0064] exist Figure 3-4 The advantages of this structural feature include the addition of a micro-wedge angle to the output surface of a conventional Wollaston prism, ensuring that the direction of the output o-beam or e-beam is parallel to the incident light within the center wavelength range. Embodiments with this design feature increase the separation angle and distance between the o-beam and e-beam compared to Lochte prisms, while this small wedge angle allows for almost negligible dispersion over a relatively wide wavelength range. In one example, the crystal is a MgF2 crystal with a small refractive index difference and a single ultraviolet laser wavelength.

[0065] exist Figure 5-6 The advantages of prominent features in the structure include a composite polarizing prism feature that, when combined in the disclosed arrangement, expands the numerical aperture of the polarizing prism.

[0066] exist Figure 8-9 The advantages of this structure include the use of air gap structures to construct composite crystal structures that function similarly to previously walk-through crystals. However, these designs / implementations require approximately one-fifth the crystal material of conventional walk-through crystals, and this crystal material can readily produce large spacing between ordinary wide-spot and very wide-spot beams.

[0067] The disclosed structures are suitable for fabricating high-power laser isolators, including isolators for high-power far-infrared CO2 lasers and adjustable optical attenuators. For example, quasi-walk-away crystal structures with larger spot sizes can be fabricated using Wollaston, Lochon, single small-wedge-angle birefringent crystals, and other low-cost and low-birefringence-index-difference crystals, cubic crystals, or optical glasses with thin-wedge-angle birefringent crystals. This can achieve extinction ratios of 30-40 dB and damage thresholds at least an order of magnitude higher. These structures are also suitable for deep-ultraviolet attenuators and isolators made of birefringent crystals (such as MgF2 and CaF2), and CO2 attenuators made of germanium-assisted large birefringent crystal sheets.

[0068] Unless the specific arrangements described herein are mutually exclusive, the various embodiments described herein can be combined, in whole or in part, to enhance system functionality or create complementary functions. Similarly, aspects of the embodiments can be implemented in independent arrangements. Therefore, the above description is given by way of example only and can be modified in detail within the scope of this invention.

[0069] Regarding the use of virtually any plural or singular terms herein, those skilled in the art can convert plural to singular or vice versa as appropriate to the context or application. For clarity, various singular / plural arrangements may be explicitly described herein. Unless otherwise stated, reference to an element in the singular does not imply "one and only one," but rather "one or more." Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is explicitly stated in the foregoing description.

[0070] Generally, the terminology used herein, and particularly in the appended claims (e.g., the body of the appended claims), is intended to be “open-ended” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “including but not limited to,” etc.). Additionally, in instances where the convention of “at least one of A, B, and C” is used, such a construction generally implies that a person skilled in the art will understand the convention (e.g., “a system having at least one of A, B, and C” will include, but is not limited to, systems that include A alone, B alone, C alone, both A and B, both A and C, both B and C, or both A, B, and C). Furthermore, phrases presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to include one term, any one of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibility of “A” or “B” or “A and B.”

[0071] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are to be regarded in all respects as illustrative rather than restrictive. Therefore, the scope of the invention is indicated by the appended claims rather than by the foregoing description. All modifications falling within the meaning and scope of equivalents of the claims are to be included within the scope of the claims.

Claims

1. A beam splitter device (300, 400, 500, 600), comprising: an optical prism (310, 410, 510, 610) having a first prism body (310a, 410a, 510a, 610a) having a first optical axis (OA31, OA41, OA51, OA61), the first prism body connected to a second prism body (310b, 410b, 510b, 610b) having a second orthogonal optical axis (OA32, OA42, OA52, OA62) at a first interface (I3, I4, I5, I6) between a second face (f2) of the first prism body (310a, 410a, 510a, 610a) and a third face (f3) of the second prism body (310b, 410b, 510b, 610b), wherein the first prism body (310a, 410a, 510a, 610a) includes a first face (fl) configured to receive incident light (320, 420, 520, 620), wherein the second prism body (310b, 410b, 510b, 610b) includes a fourth face (f4) configured to output polarized light (330, 430, 530, 630), and wherein the fourth face (f4) is counter-parallel to the first face (fl).

2. The device of claim 1, wherein the fourth face (f4) is counter-parallel to the first interface (I3, I4, I5, I6).

3. The device of claim 1, wherein the polarized light output from the fourth face (f4) of the second prism body (310b, 410b, 510b, 610b) includes one of s-polarized light (S3, S4, S5, S6) and p-polarized light (P3, P4, P5, P6).

4. The device of claim 3, wherein the one of s-polarized light (S3, S4) and p-polarized light (P3, P4) extends substantially parallel to a direction (D3, D4) of the incident light (320, 420) received at the first face (fl) of the first prism body (310a, 410a).

5. The device of claim 3, wherein the second prism body (510b, 610b) includes a fifth face (f5) adjacent to the fourth face (f4) and configured to output the other of the s-polarized light (S5, S6) and the p-polarized light (P5, P6).

6. The device of claim 3, further comprising a Glan-Taylor prism (540, 640) including the second prism body (510b, 610b) and a third prism body (540a, 640a) of the optical prism (510, 610), the third prism body having a third optical axis (OA53, OA63) parallel to the second optical axis (OA52, OA62), wherein the third prism body (540a, 640a) of the Glan-Taylor prism (540, 640) has a sixth face (f6) and a seventh face (f7) opposite the sixth face (f6), the sixth face being spaced apart from the fourth face (f4) of the second prism body (510b, 610b) by an air gap (AG5, AG6).

7. The apparatus of claim 6, wherein the sixth face (f6) of the Glan-Taylor prism (540, 640) is configured to receive the one of s-polarized light (S5, S6) and p-polarized light (P5, P6).

8. The apparatus of claim 7, wherein the seventh face (f7) of the Glan-Taylor prism (540, 640) is configured to output the one of s-polarized light (S5, S6) and p-polarized light (P5, P6) received at the sixth face (f6) of the Glan-Taylor prism (540, 640).

9. The apparatus of claim 8, wherein the seventh face (f7) of the Glan-Taylor prism (540, 640) is one of: (i) parallel to the first face (fl) of the first prism body (510a, 610a); and (ii) anti-parallel to the first face (fl) of the first prism body (510a, 610a).

10. The apparatus of claim 8, wherein the sixth face (f6) of the Glan-Taylor prism (540, 640) is one of: (i) anti-parallel to the first interface (15, 16); and (ii) parallel to the fourth face (f4) of the second prism body (510b, 610b).

11. The apparatus of claim 8, wherein the sixth face (f6) of the Glan-Taylor prism (540, 640) is anti-parallel to the seventh face (f7) of the Glan-Taylor prism (540, 640).

12. The apparatus of claim 1, wherein the optical prism (310, 410, 510, 610) comprises a Wollaston prism.

13. A laser system comprising: a laser apparatus; and the beamsplitter apparatus of claim 1, wherein the incident light is generated by the laser apparatus.

14. A beamsplitter system (800, 900) comprising: a first rhomboid prism block (810) having first and second faces (fl, f2) opposite and parallel, and third and fourth faces (f3, f4) opposite and parallel, the first and second faces (fl, f2) being positioned between the third and fourth faces (f3, f4); and a first prism (830) having a fifth face (f5) spaced apart from the first face (fl) of the first rhomboid prism block (810) by an air gap (AG8), The incident light (820) received by the third surface (f3) of the first rhombic prism block (810) is output as first polarized light (P8, S9) at the first surface (f1) of the first rhombic prism block (810), and The incident light (820) received by the third surface (f3) of the first rhombic prism block (810) is reflected at the first surface (f1) of the first rhombic prism block (810), passes through the first rhombic prism block (810) toward the second surface (f2) of the first rhombic prism block (810), is reflected at the second surface (f2) of the first rhombic prism block (810), and is output as a second polarized light (S8, P9) at the fourth surface (f4) of the first rhombic prism block (810).

15. The beam splitter system according to claim 14, The first rhomboid prism block (810) has a first optical axis (OA81, OA91), and the first prism (830) has a second optical axis (OA82, OA92). One of the following conditions exists: (i) the first optical axis (OA81, OA91) and the second optical axis (OA82, OA92) are parallel; and (ii) the first optical axis (OA81, OA91) and the second optical axis (OA82, OA92) are orthogonal.

16. The beam splitter system according to claim 15, wherein the first optical axis (OA81, OA91) extends along a direction between the first face (f1) of the first rhombic prism block (810) and the second face (f2) of the first rhombic prism block (810).

17. The beam splitter system of claim 15, wherein the second optical axis (OA82, OA92) extends along a direction parallel to the sixth face (f6) of the first prism (830, 930).

18. The beam splitter system according to claim 14, wherein the first polarized light (P8, S9) output at the first face (f1) of the first rhombic prism block (810) is received by the fifth face (f5) of the first prism (830) and output at the sixth face (f6) of the first prism (830).

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