Optical filter to enhance beam quality for hgh power laser

Abstract

According to one embodiment, an optical filter for improving high-power laser beam quality may include: a main chamber housing forming an internal space; a pair of lens port modules each coupled to one side and the other side of the main chamber housing to focus an incident laser beam and collimate an emitted laser beam; an edge-type beam clipper disposed on a laser beam focusing path inside the main chamber housing and configured to allow the main lobe of the laser beam to pass through while reflecting the sub-lobes generated by aberrations; and a beam damper unit coupled to the main chamber housing and spaced apart from the edge-type beam clipper to absorb the sub-lobes reflected from the edge-type beam clipper and convert and dissipate them into heat.

Description

Technology Field

[0001] The following description concerns an optical filter for improving high-power laser beam quality. Background Technology

[0002] In general, high-power laser systems utilize a method of combining multiple laser beams to overcome the output limitations of single-fiber lasers. Among these, wavelength-controlled beam combining necessarily employs special optical systems such as diffraction gratings and off-axis parabolic mirrors (OAPs). However, due to their structural characteristics, these off-axis optical systems inevitably induce asymmetric aberrations corresponding to higher-order terms of Zernike polynomials, particularly coma aberration.

[0003] To eliminate these aberrations, a spatial filter was conventionally used to focus the laser and pass it through a fine hole (pinhole). This method improves beam quality by physically blocking noise components of higher-order modes that have deviated from the focus point.

[0004] Conventional pinhole space filters have the following critical limitations when applied to high-power laser systems.

[0005] The first issue is thermal damage and plasma generation. When a high-power laser of several kilowatts (kW) or higher is irradiated onto the edge of a minute pinhole, a rapid temperature rise causes the device to melt or the surrounding air to ionize, generating plasma. This plasma blocks or scatters the beam (Plasma Closure), which drastically degrades beam quality and causes damage to the entire optical system.

[0006] Second, there is the inefficiency of removing asymmetric aberrations. Coma aberrations have an asymmetric distribution in the shape of a comet's tail, whereas conventional circular pinholes have a symmetric structure. Therefore, there is a dilemma where reducing the size of the pinhole to remove coma aberrations excessively blocks the effective center beam, leading to significant energy loss, while conversely, increasing the size of the pinhole does not remove the aberrations.

[0007] Third, there is the difficulty of optimization. Although the degree of aberration varies depending on the laser output level or operating environment, a fixed-size pinhole cannot adjust the balance between beam quality and energy efficiency in real time.

[0008] The aforementioned background technology is one that the inventor possessed or acquired during the process of deriving the present invention, and it cannot be considered as publicly known technology disclosed to the general public prior to the filing of the present invention. The problem to be solved

[0009] The purpose of one embodiment is to provide an optical filter for improving high-power laser beam quality. means of solving the problem

[0010] According to one embodiment, an optical filter for improving high-power laser beam quality may include: a main chamber housing forming an internal space; a pair of lens port modules each coupled to one side and the other side of the main chamber housing to focus an incident laser beam and collimate an emitted laser beam; an edge-type beam clipper disposed on a laser beam focusing path inside the main chamber housing and configured to allow the main lobe of the laser beam to pass through while reflecting the sub-lobes generated by aberrations; and a beam damper unit coupled to the main chamber housing and spaced apart from the edge-type beam clipper to absorb the sub-lobes reflected from the edge-type beam clipper and convert and dissipate them into heat.

[0011] In one embodiment, the edge-type beam clipper includes a prism or block shape having a reflective surface inclined with respect to the direction of propagation of the laser beam, and a high-reflection coating for high-power lasers may be formed on the reflective surface.

[0012] In one embodiment, the optical filter may further include a linear actuator that adjusts the amount of clipping of the sub-lobe relative to the main lobe by varying the position of the edge-type beam clipper in a direction perpendicular to the path of the laser beam.

[0013] In one embodiment, the linear actuator is coupled to the lower part of the main chamber housing, and the edge-type beam clipper can be positioned in the internal space by being mounted on the upper part of a support rod that is raised by the linear actuator.

[0014] In one embodiment, the optical filter may further include a clipper holder disposed between the support rod and the edge-type beam clipper, which fixes the edge-type beam clipper and reduces heat transfer between the support rod and the edge-type beam clipper.

[0015] In one embodiment, the linear actuator may include an electric motor or a manual knob capable of position control in micrometer units.

[0016] In one embodiment, the optical filter further comprises: a gas port disposed in the main chamber housing for exhausting internal air or injecting an inert gas; and a sealing member for maintaining airtightness provided in the lens port module, beam damper unit, and gas port, wherein the sealing member can maintain the internal space in a vacuum state or an inert gas atmosphere.

[0017] In one embodiment, the main chamber housing includes a cross-shaped or T-shaped pipe structure, the lens port module is disposed at both ends in the direction of the optical axis of the laser beam, and the beam damper unit may be disposed at the branch port in the direction intersecting the optical axis.

[0018] In one embodiment, the lens port module includes an incident side port comprising a focusing lens that focuses an incident beam; and an exit side port comprising a collimating lens that has a longer focal length than the focusing lens and converts the focused beam into parallel light, and the lens port module can form an exit beam having a diameter enlarged relative to the diameter of the incident beam.

[0019] In one embodiment, the lens port module is configured in the form of a replaceable cartridge, and the beam magnification ratio can be adjusted by changing the focal lengths of the focusing lens and the collimating lens.

[0020] In one embodiment, the edge-type beam clipper includes a quartz material having a low coefficient of thermal expansion and high laser transmittance, and the beam damper unit includes a metal material having high thermal conductivity and may include a cooling structure.

[0021] In one embodiment, the edge-type beam clipper may be positioned to selectively block one edge of an asymmetric beam profile in correspondence with the shape of the coma aberration occurring in the off-axis optical system.

[0022] In one embodiment, the optical filter may further include an optical correction element disposed at the rear end of the edge-type beam clipper to correct the divergence angle of the passed laser beam or to control the refractive index.

[0023] In one embodiment, the beam damper unit may have a beam trap structure formed to multiplely reflect and absorb an incident reflected beam, including a conical shape or an inclined surface inside.

[0024] In one embodiment, a temperature sensor for measuring the temperature of the internal space is further included, and the cooling performance of the beam damper unit can be controlled according to the measured temperature.

[0025] An optical filter for improving the quality of a high-power laser beam according to one embodiment comprises: a housing having an inlet through which a high-power laser is incident and an outlet through which an incident laser is emitted; a focusing optical system provided inside the housing and focusing the incident laser beam; a reflective edge clipper positioned at an angle with respect to the optical axis of the laser beam, positioned in a focal area of ​​the focused laser beam, so as to allow the center of the laser beam to pass through and reflect aberration components in the periphery; and a beam damper coupled to the inner wall of the housing and spaced apart from the reflective edge clipper, receiving the reflected aberration components and dissipating them as thermal energy, and can prevent thermal distortion in the focal area through the physical separation between the reflective edge clipper and the beam damper.

[0026] In one embodiment, the reflective edge clipper includes a wedge-shaped prism on which the surface to which the aberration component is incident is coated with a high-reflection coating, and can refract and reflect the aberration component in the lateral direction of the housing where the beam damper is located.

[0027] In one embodiment, the beam damper includes a heat sink or cooling channel exposed to the outside of the housing and can block radiant heat transferred from the reflective edge clipper from being transferred back to the focusing optical system. Effects of the invention

[0028] An optical filter for improving high-power laser beam quality according to one embodiment can provide significant effects through the following hardware structural improvements.

[0029] First, it is possible to improve beam quality and optimize energy loss. An optical filter for improving high-power laser beam quality according to one embodiment is configured such that an edge-type clipper entering from one side is positionally variable by a micro actuator. Through this, only the asymmetric coma aberration region occurring in the off-axis optical system can be precisely tracked and clipped, thereby achieving an equivalent or greater beam quality improvement effect with less energy loss compared to the conventional pinhole method.

[0030] Second, durability and thermal stability for high-power lasers have been secured. The component that directly blocks the laser is composed of a highly reflective coated material rather than an absorptive one, and a separated structure is adopted in which reflected excess energy is directed to a beam dumper equipped with a separate cooling structure to dissipate. This fundamentally eliminates the phenomenon of heat concentration at the focusing point, enabling stable continuous operation (CW) for a long time without melting or deformation of the device.

[0031] Third, it fundamentally eliminates beam distortion caused by plasma. By forming the interior of the optical filter as a sealed vacuum chamber or an inert gas-filled structure, it suppresses air breakdown and plasma generation that may occur during high-energy focusing. This enables the maintenance of a clean beam profile without scattering or reabsorption.

[0032] Fourth, it offers excellent ease of maintenance and system scalability. The edge clipper, beam damper, and drive unit are configured in a modular flange form, making it easy to replace only the relevant parts in the event of damage. Furthermore, by simply changing the clipper coating and beam damper material to match the laser wavelength, it possesses versatility that allows for flexible application to high-power laser systems across various wavelength bands. Brief explanation of the drawing

[0033] FIG. 1 is a schematic diagram illustrating a wavelength-controlled beam-coupled laser system according to one embodiment. FIG. 2 is a diagram schematically illustrating the focused beam profile of a wavelength-controlled beam-coupled laser according to one embodiment. FIG. 3 is a schematic diagram illustrating an optical filter using an edge-type beam clipper according to one embodiment. Referring to FIG. 4, this is an exploded perspective view illustrating an edge-type optical filter according to one embodiment. FIG. 5 is a perspective view illustrating an edge-type beam clipper assembly according to one embodiment. FIG. 6 is an exploded perspective view showing an enlarged view of part A of FIG. 5. FIG. 7 illustrates a correlation graph of beam quality and energy loss rate according to the position of an edge-type beam clipper according to one embodiment. FIG. 8 is a flowchart schematically illustrating a method of operating an edge-type optical filter according to one embodiment. FIG. 9 is a schematic diagram illustrating an optical filter using an edge-type beam clipper according to one embodiment. Specific details for implementing the invention

[0034] Embodiments are described in detail below with reference to exemplary drawings. It should be noted that when assigning reference numerals to the components of each drawing, the same components are assigned the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments, if it is determined that a detailed description of related known configurations or functions would hinder understanding of the embodiments, such detailed description is omitted.

[0035] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments. These terms are intended only to distinguish the components from other components, and the nature, order, or sequence of the components is not limited by the terms. Where it is stated that a component is "connected," "combined," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but that another component may also be "connected," "combined," or "connected" between each component.

[0036] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the description in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0037] FIG. 1 is a schematic diagram illustrating a wavelength-controlled beam-coupled laser system according to one embodiment.

[0038] Referring to FIG. 1, a wavelength-controlled beam-coupled laser system (100) according to one embodiment may include a fiber laser array (101), a multi-wavelength laser beam (102), an off-axis parabolic mirror (103), a diffraction grating (104), and a coupled high-power laser beam (105).

[0039] In one embodiment, the fiber laser array (101) may be configured in a form in which a plurality of fiber laser elements having different center wavelengths are arranged, thereby enabling the simultaneous emission of a plurality of laser beams. The multi-wavelength laser beams (102) emitted here each have a predetermined wavelength band and may propagate toward an off-axis parabolic mirror (103) in a spatially arranged state.

[0040] In one embodiment, the off-axis parabolic mirror (103) may be configured to reflect a multi-wavelength laser beam (102) and transmit it to a diffraction grating (104). In this case, the off-axis parabolic mirror (103) may perform the role of an off-axis optical system that collimates incident beams into parallel light or reflects them at a specific angle. Due to the characteristics of such an off-axis optical system, the profile of the reflected beam may include a coma aberration component having an asymmetric shape with respect to the direction of propagation of the beam.

[0041] In one embodiment, the diffraction grating (104) may be configured to diffract multi-wavelength laser beams (102) incident at different angles from an off-axis parabolic mirror (103) and align them to a single optical axis. That is, the diffraction grating (104) may perform wavelength-controlled spectral beam combining by spatially overlapping the beams through a diffraction angle corresponding to the wavelength difference of each beam.

[0042] In one embodiment, the combined high-power laser beam (105) may be a high-energy laser beam that is combined in a diffraction grating (104) and emitted in the form of a single beam. An optical filter according to various embodiments of the present invention may be positioned at the rear end of the path of the combined high-power laser beam (105) and may function to improve the quality of the final output beam by removing aberration components generated in an off-axis parabolic mirror (103), etc.

[0043] FIG. 2 is a diagram schematically illustrating the focused beam profile of a wavelength-controlled beam-coupled laser according to one embodiment.

[0044] Referring to FIG. 2, the focused beam profile of a wavelength-controlled beam-coupled laser according to one embodiment may include a main beam lobe (110) and a sub-beam lobe (111).

[0045] In one embodiment, the main beam lobe (110) may refer to a central region (Main core) where the energy density is most concentrated when the combined high-power laser beam (105) is focused. This is the main output component targeted by the laser system and, ideally, may have a circular shape that approximates a Gaussian distribution.

[0046] In one embodiment, the sub-beam lobe (111) may refer to a tail shape or an asymmetric energy distribution region observed at the periphery of the main beam lobe (110). Due to coma aberration generated while passing through an off-axis optical system, such as the off-axis parabolic mirror (103) described in FIG. 1, energy may flow down or spread out to one side of the main beam lobe (110). Such a sub-beam lobe (111) may act as a noise component that degrades beam quality by increasing the beam diameter in the far-field. An edge-type beam clipper according to one embodiment of the present invention may be positioned to selectively block only this asymmetric sub-beam lobe (111) region.

[0047] FIG. 3 is a schematic diagram illustrating an optical filter using an edge-type beam clipper according to one embodiment.

[0048] Referring to FIG. 3, an optical filter (200) (hereinafter referred to as the "optical filter") using an edge-type beam clipper according to one embodiment may include a laser beam (201), an incident beam focusing lens (202), an outgoing beam collimating lens (203), an edge-type beam clipper (204), a beam damper (205), and a clipping laser (206).

[0049] In one embodiment, the laser beam (201) may be a high-power laser beam incident on an incident beam focusing lens (202) having a predetermined incident beam diameter (D1). The incident beam focusing lens (202) may be an optical element having a first focal length (f1) and may be configured to focus a parallel incident laser beam (201) into a focal area inside the chamber. The exit beam collimator (203) may be spaced apart from and share an optical axis with the incident beam focusing lens (202), and may have a second focal length (f2). The exit beam collimator (203) may convert the beam that passes through the focal point and diverges again into parallel light and exit. At this time, the exit beam diameter (D2) of the final beam exited may be determined in proportion to the ratio of the focal lengths (f2 / f1) of the incident beam focusing lens (202) and the exit beam collimator (203). For example, by designing the second focal length (f2) to be longer than the first focal length (f1), the optical filter (200) of the present invention can be configured to simultaneously perform the function of a beam expander that expands the diameter of the beam.

[0050] In one embodiment, an edge-type beam clipper (204) may be positioned on the focusing path of the beam formed by the incident beam focusing lens (202), particularly near the beam waist. The edge-type beam clipper (204) may be inserted into a portion of the beam cross-section to allow the main beam lobe (110) described in FIG. 2 to pass through, while physically blocking aberration components such as the sub-beam lobe (111). Specifically, the edge-type beam clipper (204) may include a reflective surface inclined with respect to the beam propagation direction to form a clipping laser (206) by reflecting the blocked sub-beam lobe components in a lateral direction without absorbing them.

[0051] In one embodiment, the beam damper (205) may be positioned in the path of the clipping laser (206) reflected from the edge-type beam clipper (204). The beam damper (205) may be configured to absorb the high-energy clipping laser (206), convert it into heat, and emit it outward to dissipate it. By positioning the beam damper (205) physically separated from the edge-type beam clipper (204), the heat generated during the aberration removal process can be thermally isolated from being transferred to the main optical system, such as the focusing lens (202) or the collimating lens (203).

[0052] Referring to FIG. 4, this is an exploded perspective view illustrating an edge-type optical filter according to one embodiment.

[0053] Referring to FIG. 4, an edge-type optical filter (300) according to one embodiment may include a main chamber housing (310), a lens port module (320), a lens (321), a lens mount (322), a first sealing member (323), a beam damper flange (330), a beam damper unit (331), a second sealing member (332), a gas port flange (340), a gas fitting (341), a third sealing member (342), an actuator port flange (350), a linear actuator (351), and a fourth sealing member (352).

[0054] In one embodiment, the main chamber housing (310) may be a hollow cross-shaped or T-shaped pipe structure forming an internal space. The main chamber housing (310) serves as a base frame to which each component is joined and can provide a sealed chamber environment that physically isolates the internal optical path from the external environment.

[0055] In one embodiment, the lens port module (320) may be coupled to both ends of the main chamber housing (310), namely the incident side and the exit side of the laser beam. The lens port module (320) may be configured to include a lens (321), which is an optical element for focusing or collimating the laser beam; a lens mount (322), which firmly secures the lens (321); and a first sealing member (323) in the form of an O-ring, which maintains airtightness at the coupling portion.

[0056] In one embodiment, the beam damper unit (331) may be coupled to one side branch port (e.g., upper port) of the main chamber housing (310) via the beam damper flange (330). It may be configured to absorb a reflected aberration beam (bu-lobe) from within and convert and dissipate it into heat. At this time, a second sealing member (332) may be interposed between the beam damper flange (330) and the housing to maintain an internally sealed state.

[0057] In one embodiment, the gas port flange (340) may be positioned on the lower or side of the main chamber housing (310). A gas fitting (341) for gas injection or exhaust may be coupled thereto, and airtightness may be maintained through a third sealing member (342). This allows the internal space to be formed into a vacuum or filled with an inert gas such as nitrogen or argon, thereby preventing the phenomenon of air insulation breakdown that may occur during high-power laser focusing.

[0058] In one embodiment, a linear actuator (351) may be coupled to the lower part of the main chamber housing (310) through an actuator port flange (350). The linear actuator (351) may provide a driving force to finely move an internal edge-type beam clipper. A fourth sealing member (352) may be provided at the coupling portion of the actuator port flange (350) to ensure airtightness inside the chamber despite movement of the drive shaft.

[0059] FIG. 5 is a perspective view illustrating an edge-type beam clipper assembly according to one embodiment. FIG. 6 is an exploded perspective view showing an enlarged view of part A of FIG. 5.

[0060] Referring to FIGS. 5 and 6, an edge-type beam clipper assembly (360) according to one embodiment may include an edge-type beam clipper (361), a clipper holder (362), and a support rod (363).

[0061] In one embodiment, the edge-type beam clipper (361) may be an optical member positioned in the focal point region of a laser beam to perform substantial filtering. The edge-type beam clipper (361) may be formed in the shape of a prism or a wedge block having a reflective surface inclined at a predetermined angle with respect to the direction of propagation of the incident laser beam. A high-reflection coating capable of withstanding a high-power laser may be formed on the reflective surface to prevent absorption of aberration components, i.e., bu lobes, and to reflect them in the direction of the beam damper (331). The edge-type beam clipper (361) may be made of a quartz or fused silica material having high laser transmittance and a low coefficient of thermal expansion, thereby minimizing deformation caused by high heat.

[0062] In one embodiment, the clipper holder (362) may have the shape of a mounting tray or bracket that accommodates and secures the lower end of the edge-type beam clipper (361). The clipper holder (362) may be configured to physically support the edge-type beam clipper (361) and, at the same time, perform an insulating function to block fine radiant heat that may be generated from the clipper from being directly transferred to the lower support rod (363) or drive unit. To this end, the clipper holder (362) may be formed of a ceramic or heat-resistant alloy material with low thermal conductivity.

[0063] In one embodiment, the support rod (363) may be a cylindrical shaft member that is coupled to the lower surface of the clipper holder (362) and extends downward. The lower end of the support rod (363) may be connected to the drive shaft of the linear actuator (351) shown in FIGS. 4 and 5. By receiving power from the linear actuator (351) in this way, the edge-type beam clipper (361) may be precisely raised and lowered in the diameter direction (Z-axis direction) of the beam, thereby allowing for variable control of the beam clipping amount.

[0064] FIG. 7 illustrates a correlation graph of beam quality and energy loss rate according to the position of an edge-type beam clipper according to one embodiment.

[0065] Referring to FIG. 7, a correlation graph of beam quality and energy loss rate according to the position of an edge-type beam clipper according to one embodiment may include the position of edge clipper on the horizontal axis, beam quality on the left vertical axis, energy loss on the right vertical axis, and curves of change therefrom.

[0066] In one embodiment, the horizontal axis of the graph may represent the physical position in micrometers where the edge-type beam clipper (361) enters toward the center of the beam. Position '0' may represent an initial state where the edge-type beam clipper does not block any coma aberration components, and as the value increases, it may mean that the edge-type beam clipper is inserted deeper into the cross-section of the beam, and the amount of clipping increases.

[0067] In one embodiment, referring to the beam quality curve on the left vertical axis, when the position of the edge beam clipper is 0, the beam quality value is approximately 2.67, which may indicate a state where the beam quality is degraded due to coma aberration. As the edge beam clipper advances (as the position value increases), the beam quality value may show a tendency to gradually decrease. This means that the absolute value of the beam quality decreases, which suggests that the quality of the laser beam is being improved through the removal of physical aberrations.

[0068] In one embodiment, referring to the energy loss curve on the right vertical axis, the ratio of the beam energy removed may show a tendency to increase exponentially as the position of the edge-type beam clipper moves. This may be an inevitable loss due to the clipping of aberration components, namely some energy of the main lobe as well as the sub-lobes.

[0069] As a specific embodiment, when the edge-type beam clipper reaches a position of 70 micrometers, the beam quality can be improved to approximately 2.23, showing an improvement effect of about 20% compared to the initial state, but at this time, an energy loss of about 5.2% may occur. Furthermore, when it enters a position of 90 micrometers, the beam quality can be dramatically improved to about 1.72, but it can be confirmed that the energy loss also increases rapidly to about 18.7%. Therefore, the optical filter of the present invention can be configured to operate by using a linear actuator (351) to selectively determine the optimal point (trade-off point) between the target beam quality required by the user and the allowable energy loss range.

[0070] FIG. 8 is a flowchart schematically illustrating a method of operating an edge-type optical filter according to one embodiment.

[0071] Referring to FIG. 8, the operation method of an edge-type optical filter according to one embodiment may include an initial state measurement step (510), a variable clipping and measurement step (520), a step of determining whether a target has been reached (530), and a beam clipper fixing and operation step (540).

[0072] In one embodiment, the initial state measurement step (510) may be a process of determining the state of the source laser beam before operating the optical filter in earnest. In this step, the linear actuator (351) may be controlled to move the edge-type beam clipper (361) completely outside the path of the laser beam (i.e., a standby position that does not interfere with the beam). Afterward, the beam quality and beam output of the source laser beam in an interference-free state may be measured and stored as reference values.

[0073] In one embodiment, the variable clipping and measurement step (520) may be a process of removing aberrations by performing physical filtering. The edge-type beam clipper (361) may be moved slightly toward the beam's focusing point to clip a portion of the edge (sub-lobe region) of the focused beam. As the edge-type beam clipper (361) enters the beam, the amount of aberration component that is reflected and removed may change, and in this state, the changed beam quality and beam output may be measured again in real time.

[0074] In one embodiment, the target attainment determination step (530) may be a process of determining whether the measured data meets the target value set by the user. As previously described in FIG. 7, since there is a trade-off relationship between beam quality improvement and energy loss, the user may set the target beam quality value within an acceptable range of energy loss. If the measured value does not reach the target, the process may return to the variable clipping and measurement step (520) to readjust the position of the edge beam clipper (361) (advance or retract).

[0075] In one embodiment, the beam clipper fixing and operation step (540) can be performed when an optimal performance point is secured. When the measured beam quality and beam output satisfy the target conditions, the position of the edge-type beam clipper (361) can be physically fixed at the corresponding coordinates. Subsequently, by operating the laser system normally while maintaining the optimized filtering state, a stable high-quality laser beam can be output.

[0076] FIG. 9 is a schematic diagram illustrating an optical filter using an edge-type beam clipper according to one embodiment.

[0077] Referring to FIG. 9, an optical filter (400) with an added optical correction element according to one embodiment may include a laser beam (401), an incident beam focusing lens (402), an outgoing beam collimating lens (403), an edge-type beam clipper (404), a beam damper (405), a clipping laser (406), and an optical correction element (409).

[0078] In one embodiment, the basic functions and arrangement of the laser beam (401), the incident beam focusing lens (402), the edge-type beam clipper (404), the beam damper (405), and the exit beam collimating lens (403) may be substantially the same or similar to the components of the first embodiment (200) described above with reference to FIG. 3. That is, the incident beam focusing lens (402) may focus the incident laser beam, the edge-type beam clipper (404) may reflect a bu lob, which is an aberration component, near the focal point to form a clipping laser (406), and the beam damper (405) may be configured to absorb and remove it.

[0079] In one embodiment, the optical correction element (409) may be positioned at the rear end of the edge-type beam clipper (404), specifically on the diverging beam path between the focal area of ​​the beam and the exit beam collimation lens (403). The optical correction element (409) may be an optical member for controlling the refractive index of the transmitted laser beam or for fine-tuning the optical path.

[0080] In one embodiment, specifically, during the physical blocking process by the edge-type beam clipper (404), the energy center of the beam may shift slightly or a change in the wavefront may occur. To compensate for such changes, the optical correction element (409) may be formed in the shape of a wedge having a predetermined refractive index, a parallel plate, or a lens block having a specific curvature. By doing so, the angle of incidence or position of the beam incident on the output beam collimator lens (403) is corrected, thereby enabling more precise control of the straightness and beam quality of the parallel beam that is finally output.

[0081] According to one embodiment, an optical filter for improving high-power laser beam quality may include: a main chamber housing forming an internal space; a pair of lens port modules each coupled to one side and the other side of the main chamber housing to focus an incident laser beam and collimate an emitted laser beam; an edge-type beam clipper disposed on a laser beam focusing path inside the main chamber housing and configured to allow the main lobe of the laser beam to pass through while reflecting the sub-lobes generated by aberrations; and a beam damper unit coupled to the main chamber housing and spaced apart from the edge-type beam clipper to absorb the sub-lobes reflected from the edge-type beam clipper and convert and dissipate them into heat.

[0082] In one embodiment, the edge-type beam clipper includes a prism or block shape having a reflective surface inclined with respect to the direction of propagation of the laser beam, and a high-reflection coating for high-power lasers may be formed on the reflective surface.

[0083] In one embodiment, the optical filter may further include a linear actuator that adjusts the amount of clipping of the sub-lobe relative to the main lobe by varying the position of the edge-type beam clipper in a direction perpendicular to the path of the laser beam.

[0084] In one embodiment, the linear actuator is coupled to the lower part of the main chamber housing, and the edge-type beam clipper can be positioned in the internal space by being mounted on the upper part of a support rod that is raised by the linear actuator.

[0085] In one embodiment, the optical filter may further include a clipper holder disposed between the support rod and the edge-type beam clipper, which fixes the edge-type beam clipper and reduces heat transfer between the support rod and the edge-type beam clipper.

[0086] In one embodiment, the linear actuator may include an electric motor or a manual knob capable of position control in micrometer units.

[0087] In one embodiment, the optical filter further comprises: a gas port disposed in the main chamber housing for exhausting internal air or injecting an inert gas; and a sealing member for maintaining airtightness provided in the lens port module, beam damper unit, and gas port, wherein the sealing member can maintain the internal space in a vacuum state or an inert gas atmosphere.

[0088] In one embodiment, the main chamber housing includes a cross-shaped or T-shaped pipe structure, the lens port module is disposed at both ends in the direction of the optical axis of the laser beam, and the beam damper unit may be disposed at the branch port in the direction intersecting the optical axis.

[0089] In one embodiment, the lens port module includes an incident side port comprising a focusing lens that focuses an incident beam; and an exit side port comprising a collimating lens that has a longer focal length than the focusing lens and converts the focused beam into parallel light, and the lens port module can form an exit beam having a diameter enlarged relative to the diameter of the incident beam.

[0090] In one embodiment, the lens port module is configured in the form of a replaceable cartridge, and the beam magnification ratio can be adjusted by changing the focal lengths of the focusing lens and the collimating lens.

[0091] In one embodiment, the edge-type beam clipper includes a quartz material having a low coefficient of thermal expansion and high laser transmittance, and the beam damper unit includes a metal material having high thermal conductivity and may include a cooling structure.

[0092] In one embodiment, the edge-type beam clipper may be positioned to selectively block one edge of an asymmetric beam profile in correspondence with the shape of the coma aberration occurring in the off-axis optical system.

[0093] In one embodiment, the optical filter may further include an optical correction element disposed at the rear end of the edge-type beam clipper to correct the divergence angle of the passed laser beam or to control the refractive index.

[0094] In one embodiment, the beam damper unit may have a beam trap structure formed to multiplely reflect and absorb an incident reflected beam, including a conical shape or an inclined surface inside.

[0095] In one embodiment, a temperature sensor for measuring the temperature of the internal space is further included, and the cooling performance of the beam damper unit can be controlled according to the measured temperature.

[0096] An optical filter for improving the quality of a high-power laser beam according to one embodiment comprises: a housing having an inlet through which a high-power laser is incident and an outlet through which an incident laser is emitted; a focusing optical system provided inside the housing and focusing the incident laser beam; a reflective edge clipper positioned at an angle with respect to the optical axis of the laser beam, positioned in a focal area of ​​the focused laser beam, so as to allow the center of the laser beam to pass through and reflect aberration components in the periphery; and a beam damper coupled to the inner wall of the housing and spaced apart from the reflective edge clipper, receiving the reflected aberration components and dissipating them as thermal energy, and can prevent thermal distortion in the focal area through the physical separation between the reflective edge clipper and the beam damper.

[0097] In one embodiment, the reflective edge clipper includes a wedge-shaped prism or block shape on which the surface to which the aberration component is incident is coated with a high-reflection coating, and can refract and reflect the aberration component in the lateral direction of the housing where the beam damper is located.

[0098] In one embodiment, the beam damper includes a heat sink or cooling channel exposed to the outside of the housing and can block radiant heat transferred from the reflective edge clipper from being transferred back to the focusing optical system.

[0099] Although embodiments have been described with reference to limited drawings as described above, those skilled in the art can make various modifications and variations from the description above. For example, appropriate results can be achieved even if the described techniques are performed in a different order than described, and / or components such as the described structure or device are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

Claims

Claim 1 An optical filter for improving high-power laser beam quality, comprising: a main chamber housing forming an internal space; a pair of lens port modules each coupled to one side and the other side of the main chamber housing to focus an incident laser beam and collimate an emitted laser beam; an edge-type beam clipper disposed on a laser beam focusing path inside the main chamber housing and configured to allow the main lobe of the laser beam to pass through while reflecting the sub-lobes generated by aberrations; a beam damper unit coupled to the main chamber housing and spaced apart from the edge-type beam clipper to absorb the sub-lobes reflected from the edge-type beam clipper and convert and dissipate them into heat; and a temperature sensor for measuring the temperature of the internal space, wherein the cooling performance of the beam damper unit is controlled according to the measured temperature. Claim 2 An optical filter for improving high-power laser beam quality according to claim 1, wherein the edge-type beam clipper comprises a prism or block shape having a reflective surface inclined with respect to the direction of propagation of the laser beam, and a high-reflection coating for high-power lasers is formed on the reflective surface. Claim 3 An optical filter for improving high-power laser beam quality according to claim 1, further comprising a linear actuator that adjusts the clipping amount of the sub-lobe relative to the main lobe by varying the position of the edge-type beam clipper in a direction perpendicular to the path of the laser beam. Claim 4 In paragraph 3, the linear actuator is coupled to the lower part of the main chamber housing, and the edge-type beam clipper is mounted on the upper part of a support rod that is raised by the linear actuator and is located in the internal space, an optical filter for improving high-power laser beam quality. Claim 5 An optical filter for improving high-power laser beam quality according to claim 4, further comprising a clipper holder disposed between the support rod and the edge-type beam clipper, fixing the edge-type beam clipper and reducing heat transfer between the support rod and the edge-type beam clipper. Claim 6 In paragraph 3, the linear actuator is an optical filter for improving high-power laser beam quality, comprising an electric motor or a manual knob capable of position control in micrometer units. Claim 7 An optical filter for improving high-power laser beam quality according to claim 1, further comprising: a gas port disposed in the main chamber housing for exhausting internal air or injecting an inert gas; and a sealing member for maintaining airtightness provided in the lens port module, beam damper unit, and gas port, wherein the sealing member maintains the internal space in a vacuum state or an inert gas atmosphere. Claim 8 An optical filter for improving high-power laser beam quality according to claim 1, wherein the main chamber housing includes a cross-shaped or T-shaped pipe structure, the lens port module is disposed at both ends in the direction of the optical axis of the laser beam, and the beam damper unit is disposed at the branch port in the direction intersecting the optical axis. Claim 9 In claim 1, the lens port module comprises an incident side port including a focusing lens that focuses an incident beam; and an exit side port including a collimating lens that has a longer focal length than the focusing lens and converts the focused beam into parallel light, and the lens port module is an optical filter for high-power laser beam quality improvement that forms an exit beam having a diameter enlarged relative to the diameter of the incident beam. Claim 10 In claim 9, the lens port module is configured in the form of a replaceable cartridge, and the optical filter for improving high-power laser beam quality is capable of adjusting the beam magnification ratio by changing the focal lengths of the focusing lens and the collimating lens. Claim 11 An optical filter for improving high-power laser beam quality according to claim 1, wherein the edge-type beam clipper comprises a quartz material, the beam damper unit comprises a metal material, and the cooling structure comprises a cooling structure. Claim 12 In claim 1, the edge-type beam clipper is an optical filter for improving high-power laser beam quality that is positioned to selectively block one edge of an asymmetric beam profile in response to the shape of a coma aberration occurring in an off-axis optical system. Claim 13 An optical filter for improving high-power laser beam quality according to claim 1, further comprising an optical correction element disposed at the rear end of the edge-type beam clipper and for correcting the divergence angle of the passed laser beam or controlling the refractive index. Claim 14 delete Claim 15 An optical filter for improving the quality of a high-power laser beam, comprising: a housing having an inlet for an incident high-power laser and an outlet for an emitted high-power laser; a focusing optical system provided inside the housing and focusing the incident laser beam; a reflective edge clipper positioned at an angle to the optical axis of the laser beam, positioned in the focal region of the focused laser beam, so as to allow the center of the laser beam to pass through while reflecting aberration components in the periphery; and a beam damper coupled to the inner wall of the housing and spaced apart from the reflective edge clipper, receiving the reflected aberration components and dissipating them as thermal energy, wherein the physical separation between the reflective edge clipper and the beam damper prevents thermal distortion in the focal region, and the beam damper includes a heat sink or cooling channel exposed to the outside of the housing, and blocks radiant heat transferred from the reflective edge clipper from being back-transmitted to the focusing optical system. Claim 16 In claim 15, the reflective edge clipper comprises a wedge-shaped prism or block shape having a surface on which the aberration component is incident that is coated with a high-reflection coating, and is an optical filter for improving high-power laser beam quality that refracts and reflects the aberration component in the lateral direction of the housing where the beam damper is located. Claim 17 delete

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