Beam shaper for a vcSEL array light source

Abstract

The application discloses a beam shaping mirror for a VCSEL array light source, the VCSEL array light source comprising at least one annular array unit, each annular array unit being composed of a plurality of VCSEL chips; the beam shaping mirror comprising at least one first shaping mirror corresponding to the annular array unit, the first shaping mirror comprising a plurality of prisms corresponding to the VCSEL chips, the light beam exit surface of each prism being parallel to the light beam entrance surface, and having a preset inclination angle along the X axis and / or the Y axis; the laser beams emitted by the VCSEL chips of each annular array unit are incident from the light beam entrance surface of the corresponding prism, refracted in the prism, and then emitted from the light beam exit surface of the corresponding prism, and the output light beams are parallel to the respective input light beams. The application can reduce the spacing between the light source arrays, compress the non-light-emitting area, and arrange the emitted laser beams closely, so that the beam quality of the output laser is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser technology, in particular to a beam shaping mirror for a VCSEL array light source. BACKGROUND

[0002] In recent years, with the improvement of power and brightness, the vertical-cavity surface-emitting laser (VCSEL) has become a new type of pumping source for full solid-state lasers. Compared with the traditional edge-emitting semiconductor laser diode, the VCSEL has the following more attractive advantages: 1) smaller temperature drift (0.06nm / ℃), which can match the laser crystal absorption spectrum in a wide temperature range; 2) the divergence angles of the light beams in each direction are the same, which is easier to shape as a pumping source; 3) simple manufacturing process and low cost; 4) can be integrated in a two-dimensional plane in any way to achieve high-power laser output. By manufacturing a large-size two-dimensional plane array, the output power can reach hundreds of watts or even thousands of watts, and the electro-optical conversion efficiency is very high (usually > 42%); the above advantages make it possible to replace the traditional edge-emitting semiconductor laser diode as a pumping source for full solid-state lasers.

[0003] However, due to packaging limitations, high-power VCSELs usually use multiple VCSEL chip array integration to obtain an m x n array light source (m is the number of chips contained in each row, n is the number of chips contained in each column), and there is a non-emitting area between the chips (Zhou D, Seurin J-F, Xu G, Leeuwen RV, Miglo A, Wang Q, Kovsh A, and Ghosh C, Progress on high-power 808nm VCSELs and applications, Proc. SPIE, 2017, 10122: 33-41.). This results in a larger light source area and insufficient utilization of the array area, and the output beam quality is poor; as a pump source for end-pumped solid-state lasers, the focused spot is large and the beam waist is short, resulting in poor laser efficiency and beam quality. SUMMARY

[0004] In view of the problem of non-emitting area between the VCSEL array chips and poor beam quality in the prior art, the present application provides a beam shaping mirror for a VCSEL array light source, which can compress the beam spacing and improve the beam quality of the VCSEL.

[0005] The application discloses a light beam shaping mirror for a VCSEL array light source, the VCSEL array light source comprising at least one annular array unit, each annular array unit being composed of a plurality of VCSEL chips; the light beam shaping mirror comprising at least one first shaping mirror corresponding to the annular array unit;

[0006] The first shaping mirror is arranged in the Z-axis direction of the annular array unit, and the first shaping mirror comprises a plurality of prisms corresponding to the VCSEL chips, the light beam exit surface of each prism being parallel to the light beam entrance surface and having a preset inclination angle along the X-axis and / or the Y-axis.

[0007] The laser beams emitted by the VCSEL chips of each annular array unit are incident on the light beam entrance surfaces of the corresponding prisms at preset angles, are refracted in the prisms and are then emitted from the light beam exit surfaces of the corresponding prisms, and the output beams are parallel to the respective input beams and are arranged more closely than the input beams.

[0008] As a further improvement of the application, the VCSEL array light source comprises one annular array unit composed of VCSEL chips arranged in an N-sided polygon, and the first shaping mirror is composed of N prisms, wherein N is greater than or equal to 3; the plurality of laser beams are converged to the center by the first shaping mirror.

[0009] As a further improvement of the application, when the annular array units are multiple, the light beam shaping mirror further comprises a second shaping mirror.

[0010] The second shaping mirror is arranged in the Z-axis direction of the first shaping mirror, and the second shaping mirror corresponds to the plurality of prisms of the first shaping mirror, the light beam exit surface of each prism being parallel to the light beam entrance surface and having a preset inclination angle along the X-axis and / or the Y-axis.

[0011] The output beams of each first shaping mirror are incident on the light beam entrance surfaces of the corresponding prisms of the second shaping mirror at preset angles, are refracted in the prisms and are then emitted from the light beam exit surfaces of the corresponding prisms, and the output beams are parallel to the respective input beams and are arranged more closely than the input beams.

[0012] As a further improvement of the application, the VCSEL chips are square chips or quarter-circle chips.

[0013] As a further improvement of the application, the light beam entrance surface and the light beam exit surface of each prism are coated with an anti-reflection film corresponding to the wavelength of the light emitted by the VCSEL.

[0014] As a further improvement of the application, in the X-Z plane:

[0015] n0sinθ 1x =n1sinθ 2x

[0016] b x =z*cos theta 0x *tan theta 2x

[0017] In the formula, n0 is the air refractive index, n1 is the prism refractive index, theta 1x is the incident angle of the light incident to the prism incident surface, theta 2x is the refraction angle of the light in the prism, z is the length of the prism in the Z-axis direction, b x is the translation distance of the outgoing light relative to the incident light in the X-axis direction, theta 0x is the tilt angle of the beam incident surface of the prism along the X-axis;

[0018] On the Y-Z plane:

[0019] n0*sin theta 1y =n1*sin theta 2y

[0020] b y =z*cos theta 0y *tan theta 2y

[0021] In the formula, theta 1y is the incident angle of the light incident to the prism incident surface, theta 2y is the refraction angle of the light in the prism, b y is the translation distance of the outgoing light relative to the incident light in the Y-axis direction, theta 0y is the tilt angle of the beam incident surface of the prism along the Y-axis.

[0022] Compared with the prior art, the beneficial effects of the present application are:

[0023] The beam shaping mirror of the present application can reduce the spacing between the light source arrays, compress the non-emitting area, and arrange the outgoing laser beams closely, thereby greatly improving the beam quality of the output laser, and the beam shaping mirror has the advantages of compact structure, small light loss, etc. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the axonometric view of the beam shaping mirror for VCSEL array light source disclosed by the present application;

[0025] Figure 2 is the front view of the 2x2 VCSEL array light source disclosed by the present application embodiment 1;

[0026] Figure 3 is the beam distribution diagram of the VCSEL array light source output laser disclosed by the present application embodiment 1;

[0027] Figure 4 Front view of the beam shaping structure of the VCSEL array light source disclosed in Embodiment 1 of the present application;

[0028] Figure 5 Axonometric view of the beam shaping structure of the VCSEL array light source disclosed in Embodiment 1 of the present application;

[0029] Figure 6 Schematic diagram of the beam distribution of the output laser beam of the VCSEL array light source disclosed in Embodiment 1 of the present application after passing through the beam shaping mirror;

[0030] Figure 7 Front view of the 2x2 VCSEL array light source disclosed in Embodiment 2 of the present application;

[0031] Figure 8 Schematic diagram of the beam distribution of the output laser beam of the VCSEL array light source disclosed in Embodiment 2 of the present application;

[0032] Figure 9 Front view of the beam shaping structure of the VCSEL array light source disclosed in Embodiment 2 of the present application;

[0033] Figure 10 Axonometric view of the beam shaping structure of the VCSEL array light source disclosed in Embodiment 2 of the present application;

[0034] Figure 11 Schematic diagram of the beam distribution of the output laser beam of the VCSEL array light source disclosed in Embodiment 2 of the present application after passing through the beam shaping mirror.

[0035] In the drawings:

[0036] 1. VCSEL array light source; 11. First VCSEL chip; 12. Second VCSEL chip; 13. Third VCSEL chip; 14. Fourth VCSEL chip; 15. Non-emitting region; 2. Beam shaping mirror; 21. First prism; 22. Second prism; 23. Third prism; 24. Fourth prism. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0038] The present application will be described in further detail below in connection with the drawings:

[0039] The application provides a beam shaping mirror for a VCSEL array light source, the VCSEL array light source comprising at least one annular array unit, each annular array unit being composed of a plurality of VCSEL chips, the beam shaping mirror comprising at least one first shaping mirror corresponding to the annular array unit; wherein the annular array unit is composed of N-polygonally arranged VCSEL chips, the first shaping mirror is composed of N prisms, N≥3, and the plurality of laser beams are converged to the center by the first shaping mirror.

[0040] Specifically,

[0041] When the VCSEL array light source has one annular array unit, i.e. 4 VCSEL chips are arranged in 2×2, 5 VCSEL chips are arranged in a pentagon, 6 VCSEL chips are arranged in a hexagon, etc.; the first shaping mirror is arranged in the Z-axis direction of the annular array unit, the first shaping mirror comprises a plurality of prisms corresponding to the VCSEL chips, such as 4 prisms, 5 prisms and 6 prisms; the beam exit surface of each prism is parallel to the beam entrance surface, and has a preset inclination angle along the X-axis and / or the Y-axis, such as the first shaping mirror structure corresponding to 2×2 VCSEL chips shown in the figure. Figure 1 The laser beams emitted by the VCSEL chips of the annular array unit respectively enter the beam entrance surface of the corresponding prism at a preset angle, are refracted in the prism, and are respectively emitted from the beam exit surface of the corresponding prism, the output beams are parallel to the respective input beams, and the arrangement of the output beams is more compact than that of the input beams.

[0042] When the VCSEL array light source comprises 9 VCSEL chips, the 9 VCSEL chips are arranged in 3×3; at this time, the first shaping mirror comprises 8 prisms and a central light-transmitting flat plate, the 8 prisms correspond to the 8 peripheral VCSEL chips, the light-transmitting flat plate corresponds to the central VCSEL chip, and the VCSEL chip does not shift through the light-transmitting flat plate; the 8 prisms converge the laser beams of the 8 peripheral VCSEL chips to the center to compress the beam spacing and improve the beam quality of the VCSEL; that is, the left laser beam is shifted to the right, the upper left laser beam is shifted to the right lower side, the lower left laser beam is shifted to the right upper side, the right laser beam is shifted to the left, the upper right laser beam is shifted to the left lower side, the lower right laser beam is shifted to the left upper side, the upper laser beam is shifted downward, and the lower laser beam is shifted upward.

[0043] When the ring array unit is multiple, the beam shaping mirror further comprises a second shaping mirror; when the VCSEL array light source has 4 ring array units, each ring array unit comprises 4 VCSEL chips arranged in 2x2, that is, the VCSEL array light source comprises 16 VCSEL chips arranged in 4x4; at this time, the number of the first shaping mirror is 4, the number of the second shaping mirror is 1, and the first shaping mirror and the second shaping mirror each have 4 prisms. The second shaping mirror is arranged in the Z-axis direction of the first shaping mirror, the second shaping mirror corresponds to the plurality of prisms of the first shaping mirror, the light beam exit surface of each prism is parallel to the light beam incident surface, and has a preset inclination angle along the X-axis and / or the Y-axis; the output light beam of each first shaping mirror is incident from the light beam incident surface of the corresponding prism of the second shaping mirror at a preset angle, is refracted in the prism, and is respectively emitted from the light beam exit surface of the corresponding prism, wherein the output light beam is parallel to the respective input light beam and the arrangement of the output light beam is more compact than that of the input light beam.

[0044] In addition, when the ring array unit is more, a plurality of second shaping mirrors and a third shaping mirror for converging a plurality of second shaping mirror laser beams can be correspondingly arranged to achieve the convergence of all laser beams to the center.

[0045] Further, the VCSEL chip is a square chip or a quarter circular chip.

[0046] Further, the light beam incident surface and the light beam exit surface of the prism are each coated with an anti-reflection film corresponding to the VCSEL light-emitting wavelength.

[0047] Further,

[0048] In the X-Z plane:

[0049] n0sinθ 1x =n1sinθ 2x

[0050] b x =z·cosθ 0x ·tanθ 2x

[0051] In the formula, n0 is the air refractive index, n1 is the prism refractive index, θ 1x is the incidence angle of the light incident to the prism incident surface, θ 2x is the refraction angle of the light in the prism, z is the length of the prism in the Z-axis direction, b x is the translation distance of the exit light relative to the incident light in the X-axis direction, and θ 0x is the inclination angle of the light beam incident surface of the prism along the X-axis.

[0052] In the Y-Z plane:

[0053] n0sinθ 1y= n1sinθ 2y

[0054] b y = zcosθ 0y tanθ 2y

[0055] wherein θ 1y is an incident angle of the light ray incident to the prism incident surface, θ 2y is a refraction angle of the light ray in the prism, b y is a translation distance of the emergent light relative to the incident light in the Y-axis direction, θ 0y is an inclination angle of the prism beam incident surface along the Y-axis.

[0056] Embodiment 1

[0057] In this embodiment, the VCSEL array light source 1 is composed of four square chips, i.e. a first VCSEL chip 11, a second VCSEL chip 12, a third VCSEL chip 13 and a fourth VCSEL chip 14, which are arranged in a 2x2 manner, and the spacing between the chip light-emitting areas is 1.32 mm, which is a non-light-emitting area 15, as shown in Figure 2 . The light beam output by the VCSEL array is composed of four equally spaced 2x2 light beams, as shown in Figure 3 .

[0058] The light beam shaping mirror 2 in this embodiment is composed of four prisms, i.e. a first prism 21, a second prism 22, a third prism 23 and a fourth prism 24 corresponding to the first VCSEL chip 11, the second VCSEL chip 12, the third VCSEL chip 13 and the fourth VCSEL chip 14, respectively; the light beam incident surface and the light beam emergent surface of the prisms are parallel to each other, and the angles along the X-axis and the Y-axis are both 50°, and the length of the prism along the Z-axis direction is z=3 mm.

[0059] Referring to Figure 4 and Figure 5The VCSEL array light source 1 and beam shaping mirror 2 are arranged coaxially in sequence, with the center of beam shaping mirror 2 aligned with the center of VCSEL array light source 1. The laser beam emitted by the first VCSEL chip 11 has an emission angle of 14°. Therefore, the beam incident on the inner side of the first prism 21 has an incident angle of 26°. The output beam is deflected along the X-axis towards the laser beam output by the second VCSEL chip 12, with a beam translation distance of 0.62 mm. Simultaneously, it is deflected along the Y-axis towards the laser beam output by the third VCSEL chip 13, with a beam translation distance of 0.62 mm. The output beam remains parallel to the incident beam. Similarly, the laser beams output by the second VCSEL chip 12, the third VCSEL chip 13, and the fourth VCSEL chip 14 are translated by 0.62 mm towards the laser beams output by adjacent chips after passing through the beam shaping mirror. At this point, the output beam is equivalent to the laser beams output by four chips spaced 0.08 mm apart, greatly compressing the non-light-emitting area between the chips. (Refer to...) Figure 6 The beam quality of the output laser is improved.

[0060] Example 2

[0061] In this embodiment, the VCSEL array light source consists of four quarter-circle chips arranged in a 2×2 pattern to form a circular light-emitting area. The spacing between the light-emitting areas of the chips is 2.1 mm. Figure 7 The output beam of the VCSEL array consists of four equally spaced 2×2 beams, as shown in the reference. Figure 8 In this embodiment, the beam shaping mirror consists of four prisms. The beam exit surface and the beam incident surface of the prisms are parallel to each other, with an angle of 40° along both the X and Y axes. The length of the prism along the Z axis is z = 4 mm.

[0062] Reference Figure 9 and Figure 10 The VCSEL array light source 1 and beam shaping mirror 2 are arranged coaxially, with the center of beam shaping mirror 2 aligned with the center of the VCSEL array. The laser beam emitted by the first VCSEL chip 11 has an emission angle of 14°. Therefore, the beam incident on the inner side of the first prism 21 has an incident angle of 36°. The output beam is deflected along the X-axis towards the laser beam emitted by the second VCSEL chip 12, with a beam translation distance of 1.02 mm. Simultaneously, it is deflected along the Y-axis towards the laser beam emitted by the third VCSEL chip 13, with a beam translation distance of 1.02 mm. The output beam remains parallel to the incident beam. Similarly, the laser beams emitted by the second VCSEL chip 12, the third VCSEL chip 13, and the fourth VCSEL chip 14 are translated by 1.02 mm towards the laser beams emitted by adjacent chips after passing through the beam shaping mirror. At this point, the output beam is equivalent to the laser beams emitted by four chips spaced 0.06 mm apart, greatly compressing the non-light-emitting area between the chips. (Refer to...)Figure 11 The beam quality of the output laser is improved.

[0063] The present application has the following advantages:

[0064] The beam shaping mirror can reduce the interval between the light source arrays, compress the non-emitting area, and arrange the emitted laser beams closely, thereby greatly improving the beam quality of the output laser. The beam shaping mirror has the advantages of compact structure and low light loss.

[0065] The preferred embodiments of the present application have been described above with reference to the drawings, but the present application is not limited to the above examples, and various changes and modifications can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A beam shaping mirror for a VCSEL array light source, the VCSEL array light source comprising at least one ring array unit, each ring array unit being composed of a plurality of VCSEL chips; characterized in that, The light beam shaping mirror comprises at least one first shaping mirror corresponding to the annular array unit; The first shaping mirror is arranged in the Z-axis direction of the annular array unit, and the first shaping mirror comprises a plurality of prisms corresponding to the VCSEL chips, the light beam exit surface of each prism is parallel to the light beam entrance surface, and has a preset inclination angle along the X-axis and / or the Y-axis; The laser beams emitted by the VCSEL chips of each annular array unit are respectively incident from the light beam entrance surface of the corresponding prism at a preset angle, are refracted in the prism, and are respectively emitted from the light beam exit surface of the corresponding prism, so that the output light beams are parallel to the respective input light beams and the arrangement of the output light beams is more compact than that of the input light beams; When the VCSEL array light source comprises one annular array unit, the annular array unit is composed of N-polygonally arranged VCSEL chips, the first shaping mirror is composed of N prisms, and N≥3; the plurality of laser beams are converged to the center by the first shaping mirror; When the annular array unit is multiple, the light beam shaping mirror further comprises a second shaping mirror; The second shaping mirror is arranged in the Z-axis direction of the first shaping mirror, the second shaping mirror corresponds to the plurality of prisms of the first shaping mirror, the light beam exit surface of each prism is parallel to the light beam entrance surface, and has a preset inclination angle along the X-axis and / or the Y-axis; The output light beams of each first shaping mirror are incident from the light beam entrance surface of the corresponding prism in the second shaping mirror at a preset angle, are refracted in the prism, and are respectively emitted from the light beam exit surface of the corresponding prism, so that the output light beams are parallel to the respective input light beams and the arrangement of the output light beams is more compact than that of the input light beams; In the X-Z plane: n0sinθ 1x = n1sinθ 2x b x = z cos θ 0x tan θ 2x where n0 is the refractive index of air, n1 is the refractive index of the prism, θ 1x is the incident angle of the light ray to the prism incident surface, θ 2x is the refractive angle of the light ray in the prism, z is the length of the prism in the Z-axis direction, b x is the translation distance of the emergent light relative to the incident light in the X-axis direction, θ 0x is the tilt angle of the beam incident surface of the prism along the X-axis; In the Y-Z plane: n0sinθ 1y = n1sinθ 2y b y = z cos θ 0y tan θ 2y where θ 1y is the angle of incidence of the light ray at the prism entrance face, θ 2y is the angle of refraction of the light ray within the prism, b y is the translation distance of the emergent light relative to the incident light in the Y-axis direction, θ 0y is the angle of inclination of the beam entrance face of the prism along the Y-axis.

2. The beam shaper for a VCSEL array light source according to claim 1, wherein The VCSEL chip is a square chip or a quarter circular chip.

3. The beam shaper for a VCSEL array light source according to claim 1, wherein The light beam entrance surface and the light beam exit surface of the prism are both coated with an anti-reflection film corresponding to the VCSEL light-emitting wavelength.

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