Non-gaussian laser beam excitation in laser-driven plasma x-ray sources

Abstract

A system and method for generating X-rays by delivering a series of laser pulses having non-Gaussian intensity profiles and various polarizations onto a target material, thereby generating a plasma on the target material and accelerating electrons within the plasma to produce X-rays. In a sample configuration, the system includes a laser source, optical elements for modulating the laser beam, and a target material housed in a vacuum chamber. The laser source can be an Ytterbium laser with specific repetition rates and pulse durations, and the optical elements can include lenses, waveplates, and spatial light modulators, among others. The target material can be a liquid metal, solid metal, liquid, or gas, and the laser pulses can be generated by multiple laser beams with different wavelengths.

Description

NON-GAUSSIAN LASER BEAM EXCITATION IN LASER-DRIVEN PLASMA X-RAYSOURCESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit from U.S. Provisional Patent Application Serial No. 63 / 623,176, filed January 19, 2024, and U.S. Provisional Patent Application Serial No.63 / 623,164, filed January 19, 2024, and U.S. Provisional Patent Application Serial No.63 / 623,180, filed January 19, 2024, and U.S. Provisional Patent Application Serial No.63 / 626,493, filed January 29, 2024, and U.S. Provisional Patent Application Serial No.63 / 550,575, filed February 6, 2024, which are all hereby incorporated by reference in their entirety herein.FIELD OF THE INVENTION

[0002] The present invention relates generally to systems and methods for generating X-rays and more particularly, to generating X-rays using non-Gaussian laser beams with various polarizations.BACKGROUND

[0003] X-ray generation is a critical technology used in a wide range of applications, from medical imaging and security scanning to materials analysis and scientific research. Traditional X-ray sources typically fall into two categories: (1) compact and affordable X-ray sources such as X-ray tubes, and (2) high-performance X-ray sources such as synchrotrons and linear accelerator sources. Both X-ray source categories have deficiencies and limitations in terms of size, cost, flux, and brilliance. For example, certain applications, such as semiconductor metrology, require compact high brilliance X-ray sources and the demand for higher X-ray brilliance with similar size and cost is expected to increase in the future. X-ray tubes rely on the electrostatic acceleration of electrons toward a metal anode where their kinetic energy is partially converted into X-rays. The brilliance of X-ray tubes is limited because high-intensity electron beams damage the anode. At high electron beam power, the focus spot on the anode has to be enlarged to avoid exceeding the anode’s damage threshold. The brilliance of X-ray tubes to date appears to have reached a technological limit.

[0004] Laser-driven Plasma X-ray Sources (LPXSs) are also used to generate X-rays. This approach leverages the ability of lasers to deliver high-intensity, precisely controlled energy to a target, creating conditions that can lead to the generation of X-rays. The brilliance of LPXSs can be 10 to 100 times higher than that of X-ray tubes. To our knowledge, LPXSs discussed in the published literature utilize Gaussian and near-Gaussian laser beam profiles on a target material to generate X-rays. Gaussian and near-Gaussian laser beam profiles can deliver high laser intensity to a very small area. There are challenges in terms of designing systems that can reliably produce X-rays with the desired attributes while maintaining efficiency and cost-effectiveness.

[0005] Accordingly, there is a growing demand for improvements and more efficient, compact, and versatile X-ray generation systems that can meet the needs of various industries and research fields.SUMMARY OF THE INVENTION

[0006] The following presents a simplified summary of the innovation to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0007] In one aspect, the present invention provides a method for generating X-rays by delivering one or multiple laser pulses onto a target material. Each laser pulse can have a nonGaussian intensity profile and various polarizations. The interaction of these laser pulses with the target material can generate a plasma, and the electrons in the plasma can be accelerated to produce X-rays.

[0008] Some examples of the method may include modifying a laser beam having a Gaussian or near-Gaussian intensity profile to obtain a desired non-Gaussian intensity profile with various polarizations. This modification of the laser beam can be achieved using optical elements to modulate the intensity, phase, and polarization of the laser beam. The method may also involve placing the target material in a vacuum chamber and focusing the laser pulses onto the surface of the target material.

[0009] In another aspect, the present invention provides a system for generating X-rays that includes a laser source with a linearly polarized near-Gaussian beam. A series of optical elements can be aligned with the laser source to convert the beam into one or multiple laserpulses having a non-Gaussian intensity profile and various polarizations, and to focus the nonGaussian beam on a target material. The target material, which may be housed in a vacuum chamber, can receive these laser pulses which cause a plasma generation on the target material and electron acceleration within the plasma to produce X-rays.

[0010] One or more of the following features may be included. The laser source can be an Ytterbium laser, a pulsed CO2 laser, a Thulium laser, a fiber laser, or a slab laser. The laser source can have a repetition rate range from 1Hz to 1MHz and a pulse duration range from lOfs to lOOps. In some example systems, the laser source may have a repetition rate of 5kHz, a pulse duration of 850fs, and a wavelength of 1030nm.

[0011] The non-Gaussian intensity profile can include Hermite-Gaussian modes, Laguerre- Gaussian modes, Ince-Gaussian modes, Hypergeometric-Gaussian modes, Bessel -Gaussian beams, Bessel beams, flat-top beams, or any combination of these modes and beams.

[0012] The non-Gaussian intensity profile may include Laguerre-Gaussian modes of order 00, 10, and 01*. The non-Gaussian intensity profile can include Hermite-Gaussian modes of order 00, 10, and 01.

[0013] The polarization may be other than a linear polarization and has a multipole polarization pattern. The laser pulses can be radially polarized and used with or without photon orbital angular momentum. The laser pulses may be azimuthally polarized and used with or without photon orbital angular momentum. The polarization can include left-hand circular polarization, right-hand circular polarization, or combinations of both. The polarization may include spatially dependent polarization of vector beams or vectorial vortex beams.

[0014] The optical elements can include lenses, waveplates, phase plates, spiral phase plates, polarizing plates, apertures, spatial light modulators, or deformable mirrors.

[0015] The target material may be a liquid metal or a solid metal. The target material can be a liquid or a gas. The laser pulses on the target material may be applied simultaneously by multiple lasers with different wavelengths.

[0016] The present invention provides many improvements and advantages over existing LPXS systems. For example, the non-Gaussian intensity profile and various polarizations of the claimed invention potentially produce a greater X-ray flux compared to current LPXS systems. To an extent, the present invention is laser source independent and various types of laser sources can be utilized provided their operation parameters are within similar ranges specified herein.The invention can be used in a wide range of applications, including but not limited to, semiconductor metrology, medical imaging, security scanning, non-destructive imaging, x-ray diffraction, and scientific research.

[0017] These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will be more fully understood by reference to the detailed description, in conjunction with the following figures.

[0019] FIG. 1 illustrates an example configuration of components, including laser source and optical elements, for converting a Gaussian laser beam with a linear polarization into a nonGaussian laser beam with various polarizations in accordance with an aspect of the present invention.

[0020] FIG. 2 illustrates another example configuration of components, including laser source and optical elements, for converting a Gaussian laser beam with linear polarization into a nonGaussian laser beam with various polarizations in accordance with an aspect of the present invention.

[0021] FIG. 3 A illustrates a normalized intensity profile of a non-Gaussian laser beam in comparison to a Gaussian laser beam in accordance with an aspect of the present invention.

[0022] FIG. 3B illustrates a non-limiting example with measurements of an intensity profile of a non-Gaussian laser beam in comparison to a Gaussian laser beam in accordance with an aspect of the invention.

[0023] FIG. 3C illustrates an image of a non-Gaussian intensity profile with radial polarization.

[0024] FIG. 3D illustrates an image of a non-Gaussian intensity profile with azimuthal polarization.

[0025] FIG. 4 illustrates an exemplary embodiment of an X-ray generation system configured in accordance with an embodiment of the present invention.

[0026] FIG. 5 is a flow diagram illustrating the process of generating X-rays in accordance with an aspect of the present invention.

[0027] FIG. 6 illustrates Laguerre-Gaussian modes for use with various embodiments of the present invention.

[0028] FIG. 7 illustrates Hermite-Gaussian modes for use with various embodiments of the present invention.DETAILED DESCRIPTION

[0029] The subject innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the present invention. It may be evident, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate describing the present invention.

[0030] Definitions & Terms:

[0031] In the context of the present disclosure, the following terms shall be construed in accordance with the definitions set forth below. These definitions are provided to clarify the meaning of terms as they pertain to the embodiments described herein and are intended to apply consistently throughout this application, unless the context explicitly dictates otherwise.

[0032] The terms “beam” and “pulses” are used interchangeably in this document.

[0033] The term “Gaussian beam” means laser beams or pulses having a Gaussian or nearGaussian intensity profile.

[0034] The term “non-Gaussian beam” means laser beams or pulses having a non-Gaussian intensity profile with linear polarization or various other polarizations.

[0035] The term “LPXS” means laser-driven plasma X-ray source.

[0036] The term “fs” means femtosecond.

[0037] The term “ps” means picosecond.

[0038] Gaussian Beams, Near-Gaussian Beams & Non-Gaussian Beams

[0039] A key parameter distinguishing Gaussian from non-Gaussian laser beams is the beam quality factor, denoted as M2, which quantifies how closely a laser beam approximates an ideal Gaussian beam. An ideal Gaussian beam has an M2value of 1, indicating optimal beam quality with intensity profiles following a Gaussian function. Only a beam with Gaussian profiles canbe focused by an ideal lens to a focus with a Gaussian profde without any diffraction rings surrounding the focus center.

[0040] Near-Gaussian beams closely resemble the ideal Gaussian profile but may exhibit slight deviations due to imperfections in the laser cavity or external optical components. These beams have M2values slightly greater than 1. For example, helium-neon lasers typically have an M2factor less than 1.1, indicating high beam quality.

[0041] In contrast, non-Gaussian beams possess intensity profiles that significantly deviate from the Gaussian shape, such as flat-top (top-hat) beams or beams with higher-order transverse modes (e.g., Hermite-Gaussian, Laguerre-Gaussian) that can exhibit more complex intensity profiles featuring multiple peaks and nulls. These non-Gaussian beams exhibit M2values substantially greater than 1. The increased M2value signifies that non-Gaussian beams cannot be focused to a Gaussian or near-Gaussian focus.

[0042] In summary, the M2factor serves as a critical parameter in assessing laser beam quality:• M2= 1: Indicates an ideal Gaussian beam, which is generally considered “perfect beam quality”.• M2slightly > 1: Represents near-Gaussian beams with high beam quality but not exactly a Gaussian function.• M2» 1: Corresponds to non-Gaussian beams with substantial deviations from the Gaussian function. Focusing such beams can result in foci with substantial deviations from Gaussian profiles, which may be desirable for specific applications.

[0043] Generally, the present invention provides an improved method and system for generating X-rays. Unlike conventional X-ray generation systems that utilize Gaussian (and near-Gaussian) beams with linear polarization to generate X-rays, the invention utilizes laser beams having non- Gaussian intensity profiles, with various polarizations, to interact with a target material and generate X-rays as a fluorescence (line) emission or Bremsstrahlung (continuum) emission. Non-Gaussian beams as discussed in this specification may have a controlled non-Gaussian intensity profile with linear polarization or various other polarizations specified below.

[0044] The method involves delivering one or multiple non-Gaussian laser pulses onto a target material to generate a plasma on the target material and accelerate electrons within the plasma to produce X-rays. The method may include modifying a laser beam initially having a Gaussian or near-Gaussian intensity profile with a linear polarization to obtain the desired non-Gaussian intensity profile with various polarizations. This modification of the laser beam can be achievedusing optical elements to adjust and modulate the intensity, phase, and polarization of the laser beam. Such optical elements can include lenses, waveplates, phase plates, spiral phase plates, polarizing plates, apertures, spatial light modulators, or deformable mirrors.

[0045] The system can include a laser source (e.g., Ytterbium laser) that can emit a linearly polarized near-Gaussian beam. This beam can be converted and focused into one or multiple laser pulses having a non-Gaussian intensity profile and various polarizations using a series of optical elements aligned with the laser source. In some embodiments, the non-Gaussian beam may be generated by the simultaneous application of multiple laser beams with different wavelengths and propagating the multiple laser beams through the optical elements. The system can include a target material that can be housed within a vacuum chamber. The non-Gaussian laser pulses can be delivered onto the target material causing a plasma to be produced on the target material and accelerating electrons within the plasma to produce X-rays.

[0046] Referring to FIG. 1, an example configuration of components 100, including laser source and optical elements, is depicted for converting a Gaussian laser beam with linear polarization into a non-Gaussian laser beam with various polarizations in accordance with an aspect of the present invention. Laser source 102 can have a repetition rate ranging from 1Hz to 1MHz and a pulse duration range from lOfs to lOOps. In an embodiment, laser source 102 can have a repetition rate of 5kHz, a pulse duration of 850fs, and a wavelength of 1030nm. In various embodiments, laser source 102 can be an Ytterbium laser (e.g., Yb:YAG), Thulium laser (e.g., Tm:YLF), or pulsed CO2 laser. Other types of laser sources (e.g., fiber laser, slab laser) can also be used, provided they have similar performance specifications including repetition rates, and pulse durations. In various embodiments, multiple lasers of different types can be used simultaneously as the laser source 102.

[0047] In an embodiment, laser source 102 can emit a beam 104 that has a near-Gaussian intensity profile and may be linearly polarized. Gaussian beam 104 can be propagated through one or more optical elements forming a beam modulator 106 that can adjust the intensity, phase, and polarization of the Gaussian beam 104. At this point, the modulated beam 107 can be propagated through a focusing optical element 108 that focuses the modulated beam 107 onto a target material 112. The focused beam 110 has a non-Gaussian intensity profile, with linear polarization or other polarizations, at the focus.

[0048] Referring also to FIG. 2, in an embodiment 200, some beam modulators 106 may also reflect the incoming laser beam 104 thereby changing the trajectory of the beam. The modulated beam 107 that exits the beam modulator 106 can be propagated through a focusing optical element 108 that focuses the modulated beam 107 onto the target material 112. The focused beam 110 delivered to the target material 112 has a non-Gaussian intensity profile, with linear polarization or other polarization, at the focus.

[0049] Referring to FIG. 3A, a normalized graph 300 illustrates a Gaussian laser beam intensity profile 302 compared to non-Gaussian laser beam intensity profile 304. Graph 301 in FIG. 3B provides a non-limiting example with measurements illustrating Gaussian beam 302 compared to non-Gaussian beam 304. Current LPXS systems used for generating X-rays typically utilize linearly polarized laser beams having a Gaussian intensity profile 302, and apply the Gaussian beam 302 directly to target material to generate X-rays. In contrast, the improvements to LPXS systems provided by the present invention require using laser beams having a non-Gaussian intensity profile 304 with various polarizations. For example, as shown in FIG. 3C a non- Gaussian intensity profile can have radial polarization. FIG. 3D depicts a non-Gaussian intensity profile with azimuthal polarization. Since available laser sources typically emit beams having the Gaussian intensity profile 302, the present invention uses the Gaussian beam 302 as an initial input and then converts it with optical elements to a non-Gaussian beam 304, with linear polarization or other polarizations, as discussed above in connection with FIGs. 1 and 2. In other words, the present invention takes Gaussian beam 302 as an input, modifies and converts it to a non-Gaussian beam 304 using optical elements, and applies the non-Gaussian beam 304 onto target material to create a plasma and generate X-rays. In some embodiments, the beam delivered to the target material may be generated by the simultaneous application of multiple laser beams with different wavelengths and propagating the multiple laser beams through the optical elements. The optical elements used for the modification can include lenses, waveplates, phase plates, spiral phase plates, polarizing plates, apertures, spatial light modulators, deformable mirrors, and other optical components.

[0050] Referring to FIG. 3A and FIG. 3B, the intensity profile of the Gaussian beam 302 can have a higher peak amplitude than the non-Gaussian beam 304, and the Gaussian beam 302 can have a small beam area at its peak with which to excite target material and generate X-rays. For example, as shown in graph 301, Gaussian beam 302 can have a diameter of 4 pm and a peakintensity of 7.5 x 1016W / cm2. In contrast, the intensity profile of the non-Gaussian beam 304 has lower amplitude and a wider beam area having a similar intensity level with which to excite target material and efficiently generate X-rays. The non-Gaussian beam 304 uses its laser energy for X-ray generation more efficiently, because the laser intensity is relatively homogeneous over beam area used for exciting target material. Therefore, the non-Gaussian beam 304 generates more X-rays and provides higher conversion efficiency than the Gaussian beam 302. It should be noted that the non-Gaussian beam 304 illustrated in FIG. 3 A and FIG. 3B is simply one nonlimiting example of a non-Gaussian intensity profile 304 that can be utilized in connection with the present invention. Other non-Gaussian intensity profiles having different amplitudes, widths, shapes, and other attributes can be used without deviating from the scope of the present invention.

[0051] Examples of non-Gaussian intensity profiles that can be utilized in aspects of the present invention can include intensity profiles for the Hermite-Gaussian modes, Laguerre-Gaussian modes, Ince-Gaussian modes, Hypergeometric-Gaussian modes, Bessel-Gaussian beams, Bessel beams, flat-top beams, and combinations of these intensity profiles. These example non- Gaussian beams can carry a photon orbital angular momentum. Referring to FIG. 6 and FIG. 7, in various embodiments, specific non-Gaussian intensity profiles can include Laguerre-Gaussian modes of order 00, 10, and 01* and Hermite-Gaussian modes of order 00, 10, and 01.

[0052] Examples of various polarizations that can be utilized with the non-Gaussian beam 304 in accordance with aspects of the present invention can include polarizations with a multipole pattern, radially (depicted in FIG. 3C) or azimuthally (depicted in FIG. 3D) polarized with or without photon orbital angular momentum, left-hand or right-hand circular polarization, or any combination of these options. The polarization may also include spatially dependent polarizations of vector beams and vectorial vortex beams.

[0053] To derive an optimal beam intensity profile that gives the highest total emitted X-ray flux, it is important to know the laser-to-X-ray conversion efficiency as a function of laser intensity. The number of Ka photons emitted from hot electrons can be described by the following equation.NCPiaser.Z = fl nhot( / (r)) / hot( / (r, £•),) Ngen(E, Z) / em(E,Z) 2nr dr dEwhere TV is the number of Ka photons emitted from a target with atomic number Z and laser beam power iaser, I(r) is the laser intensity at the focus as a function of radius r, / / hot is the total number of hot electrons, / hot is the electron energy distribution, E is the energy of the electron before emitting Ka photons, Ngcnis the number of Ka photons generated by a single electron, and fem is the fraction of Ka photons that escape from the target.

[0054] The number of Ka photons increases with / (r) because Whot increases with I (r) but at higher laser intensity N decreases with Z(r) because Ka photons generated at greater depth inside the target are partially absorbed on their way out of the target. High laser intensity does not necessarily give high X-ray intensity. A Gaussian beam profde, where the laser intensity is confined to a small area, does not necessarily give the highest X-ray flux. A beam profile needs to be optimized to achieve high laser-to-X-ray conversion over the beam area. An objective of the present invention is to optimize the laser focus profile / (r) in order to maximize the emitted X-ray flux N(Plaser,Z).

[0055] Referring to FIG. 4, in an exemplary embodiment, the present invention provides an X- ray generation system (e.g., LPXS) 400 that includes a laser source 402, multiple optical elements that can include a beam intensity, phase, and polarization modulator, and a target material 414 housed in a vacuum chamber 416.

[0056] The laser source 402 can be selected to have a repetition rate range from 1Hz to 1MHz and a pulse duration range from lOfs to lOOps. In an embodiment, the laser source 402 can be an Ytterbium laser having a repetition rate of 5kHz, a pulse duration of 850fs, and a wavelength of 1030nm. Other types of laser sources can be utilized provided they have comparable operating specifications including similar repetition rates and pulse durations.

[0057] In an embodiment, the laser source 402 can emit a linearly polarized near-Gaussian beam 403 that can be propagated through a telescope 404 to adjust the size of the beam 403. The adjusted beam 405 can then be propagated through a beam modulator 406 to adjust the intensity, phase, and polarization of the beam 405. The modulated beam 407 exiting the beam modulator 406 has a non-Gaussian intensity profile and can have various polarizations depending on the specifications of the selected beam modulator 406. For example, applicable non-Gaussian intensity profiles can include Hermite-Gaussian modes, Laguerre-Gaussian modes, Ince- Gaussian modes, Hypergeometric-Gaussian modes, Bessel-Gaussian beams, Bessel beams, flat- top beams, and combinations of these intensity profiles. These non-Gaussian intensity profilescan carry an orbital angular momentum. Referring to FIG. 6 and FIG. 7 , in various embodiments, the non-Gaussian intensity profiles can include Laguerre-Gaussian modes of order 00, 10, and 01* and Hermite-Gaussian modes of order 00, 10, and 01. Depending on the specifications of the selected beam modulator 406, applicable polarizations can include a polarization other than linear having a multipole polarization pattern, radially or azimuthally polarized with or without photon orbital momentum, left-hand or right-hand circular polarization, or any combination of these polarizations. The polarization may also include spatially dependent polarizations of vector beams and vectorial vortex beams.

[0058] Referring to FIG. 4, the size of the modulated beam 407 can be further adjusted by propagating the beam 407 through a telescope 408. The adjusted beam 409 can be focused using an aspheric lens 410 or other optical elements. The focused beam 412 has a non-Gaussian intensity profile, with or without linear polarization, at the focus. The focused beam 412 can then be delivered and applied to a target material 414 that may be housed in a vacuum chamber 416. The target material 414 can be a liquid metal (e.g., mercury, gallium), solid metal (e.g., copper, aluminum, silver, indium, tin, bismuth), a liquid (e.g., water, ethanol, liquid oxygen, liquid helium), or a gas (e.g., helium, neon, nitrogen, argon).

[0059] In operation, when the focused beam 412 is applied to the target material 414 a plasma 418 is produced on the target material 414 at the focus, and the electrons in the plasma 418 are accelerated to generate an X-rays 420 as fluorescence (line) emission or Bremsstrahlung (continuum) emission.

[0060] Optimal intensity profiles and polarizations may vary depending on the laser beam power, X-ray energy range, fluorescence emission, or Bremsstrahlung emission. A particular intensity profile and polarization can be optimized for a selected X-ray spectrum by using a feedback control with the X-ray flux 420 as a merit function. This involves using the measured intensity of the X-rays as a primary metric to evaluate and optimize the performance of system 400, with the goal being to maximize the amount X-ray flux collected at the target location.

[0061] Referring to FIG. 5, in an aspect, the present invention features a method of generating (500) X-rays. The method can include the steps of: (a) modifying (502) a linearly polarized laser beam initially having a Gaussian or near-Gaussian intensity profile to obtain a desired non- Gaussian intensity profile with various polarizations; (b) delivering (504) multiple non-Gaussian laser pulses having various polarizations onto a target material placed in a vacuum chamber; (c)generating (506) a plasma on the target material through interaction with the multiple nonGaussian laser pulses; and accelerating (508) the electrons in the plasma to generate X-rays. The step of modifying (502) can further include adjusting the intensity, phase, and polarization of the Gaussian or near-Gaussian intensity profile with a linear polarization.

[0062] While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims. For example, other useful implementations could be achieved if steps of the disclosed techniques were performed in a different order and / or if components in the disclosed systems were combined in a different manner and / or replaced or supplemented by other components. Accordingly, other implementations are within the scope of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A method of generating X-rays comprising: delivering a plurality of laser pulses on a target material, each laser pulse having a non-Gaussian intensity profde and various polarizations; generating a plasma on the target material through interaction with the plurality of laser pulses; and accelerating electrons in the plasma to generate X-rays.

2. The method of claim 1, wherein delivering the plurality of laser pulses includes modifying a laser beam having a Gaussian or near-Gaussian intensity profile using optical elements that modulate intensity, phase, and polarization of the laser beam to obtain the plurality of laser pulses having the non-Gaussian intensity profile and various polarizations.

3. The method of claim 1, wherein delivering the plurality of laser pulses on the target material includes placing the target material in a vacuum chamber and focusing the plurality of laser pulses onto a surface of the target material.

4. A system for generating X-rays comprising: a laser source having a linearly polarized near-Gaussian beam; a plurality of optical elements in alignment with the laser source for focusing and converting the near-Gaussian beam to a plurality of laser pulses having a non-Gaussian intensity profde and various polarizations; and a target material housed in a vacuum chamber, the target material receiving the plurality of laser pulses resulting in generation of a plasma on the target material and acceleration of electrons in the plasma to generate X-rays.

5. The system of claim 4, wherein the laser source is an Ytterbium laser, a pulsed CO2 laser, a Thulium laser, a fiber laser, or a slab laser.

6. The system of claim 4, wherein the laser source has a repetition rate range of 1Hz to 1MHz and a pulse duration range of lOfs to lOOps.

7. The system of claim 4, wherein the laser source has a repetition rate of 5kHz, pulse duration of 85Ofs, and wavelength of 1030nm.

8. The system of claim 4, wherein the non-Gaussian intensity profde comprises any of Hermite- Gaussian modes, Laguerre-Gaussian modes, Ince-Gaussian modes, Hypergeometric-Gaussian modes, Bessel-Gaussian beams, Bessel beams, flat-top beams, or any combination thereof.

9. The system of claim 4, wherein the non-Gaussian intensity profde includes Laguerre-Gaussian modes of order 00, 10, and 01*.

10. The system of claim 4, wherein the non-Gaussian intensity profde includes Hermite- Gaussian modes of order 00, 10, and 01.

11. The system of claim 4, wherein the polarization is other than linear polarization and has a multipole polarization pattern.

12. The system of claim 4, wherein the plurality of laser pulses is radially polarized and used with or without photon orbital angular momentum.

13. The system of claim 4, wherein the plurality of laser pulses is azimuthally polarized and used with or without photon orbital angular momentum.

14. The system of claim 4, wherein the polarization includes left-hand circular polarization, right-hand circular polarization, or combination thereof.

15. The system of claim 4, wherein the polarization comprises spatially dependent polarization of vector beams or vectorial vortex beams.

16. The system of claim 4, wherein the optical elements include one or more lenses, waveplates, phase plates, spiral phase plates, polarizing plates, apertures, spatial light modulators, or deformable mirrors.

17. The system of claim 4, wherein the target material is a liquid metal or a solid metal.

18. The system of claim 4, wherein the target material is a liquid or a gas.

19. The system of claim 4, wherein the plurality of laser pulses on the target material is applied simultaneously by multiple lasers.

20. The system of claim 19, wherein the multiple lasers have different laser wavelengths.

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