Systems and methods for controlling particles using projected light - Patents.com

Abstract

Systems and methods are provided for controlling particles using projected light. In some embodiments, the methods include generating a light beam using a light source and directing the light beam to a beam filter including a first mask, a first lens, a second mask, and a second lens. The methods also include forming a light pattern using the beam filter and projecting the light pattern onto a plurality of particles to control their positions in space.

Description

[Technical field]

[0001] STATEMENT REGARDING FEDERALLY FUNDED RESEARCH: This invention was made with government support under award W911NF-15-2-0061 from the ARMY / ARL and award 1720220 from the National Science Foundation. The U.S. Government has certain rights in the invention. [Background technology]

[0002] FIELD OF THE DISCLOSURE The field of the disclosure relates to systems and methods for controlling particles, and more particularly, to systems and methods for trapping particles using projected light.

[0003] The ability to confine and manipulate particles using optical techniques has paved the way for many scientific advances. For example, defect-free artificial crystals have been created using trapped particles and used to probe various fundamental principles governing interactions and materials properties. Neutral atoms have been particularly attractive because they have a well-defined quantum structure and charge neutrality, which isolates the atoms from charge-related perturbations and helps retain quantum information for longer times. In addition, neutral atoms can be individually controlled and scaled to large systems.

[0004] Atoms become trapped by the coherent interaction between the electromagnetic field of the applied light and the oscillating electric dipole moment induced in the atoms. Specifically, the electromagnetic field induces an internal atomic energy shift, which creates an effective potential that produces confinement forces. To trap atoms, the frequency of the light is typically shifted, or detuned, relative to the atomic resonance frequency. In particular, when the frequency of the light is lower than the atomic transition frequency, or "red-detuned," the induced atomic dipole moments are in phase and the atoms are attracted to the intensity maxima of the light. The strength of the attractive force depends on the magnitude of the detuning. In contrast, when the frequency is "blue-detuned," the induced moment is out of phase and the atoms are repelled from the maxima. Furthermore, the strength of the attractive / repulsive forces can be altered by controlling the intensity or power of the applied light.

[0005] Optical techniques have also been widely used to trap arrays of atoms for quantum computing and atomic clock applications. The arrays can be arranged in one-, two- or three-dimensional configurations or optical lattices. Bright, red-detuned arrays localize the atoms at local maxima, while dark, blue-detuned arrays localize the atoms at local minima. In general, dark arrays require more complex optics, but offer the important advantage of being less perturbing by localizing the atoms at lower intensities. This is important for extending the coherence time of atomic qubits and for minimizing disturbances to atoms in optical clocks.

[0006] Optical lattices are usually formed by the interference of light from different light sources. For example, a 1D lattice can be created using standing waves generated by superposing two counter-propagating laser beams. Higher dimensional optical lattices require additional light sources. For example, a 3D simple cubic lattice structure can be created by superposing three orthogonal standing waves generated using three pairs of counter-propagating light sources. However, the positions of atoms in a lattice created by the interference of counter-propagating beams are very sensitive to the optical path length. Small drifts cause differential phase shifts between the beams, which greatly affect the positions of the atoms. The phase shift can in principle be compensated for by using active stabilization, but such techniques are usually applied to single atoms. This is because of the increased complexity of the systems required to perform active stabilization for multiple atoms.

[0007] The position of the interference fringes is sensitive to the relative phase of the interfering light beams and therefore to the optical path length. Such sensitivity can be eliminated by projecting an intensity pattern that does not require interference stability. However, the projected light creates multiple optical trapping planes due to the Talbot effect, which arises from the periodic nature of phase-coherent light repeating in free space. This can result in unwanted trapping of atoms in multiple spatial planes. In an attempt to suppress this effect, some prior art techniques use different frequencies of light for each optical trap or use spatial light modulators to impart random phases to each trap. However, such approaches require a large number of components (e.g., acousto-optic deflectors, spatial light modulators, diffractive, polarization-sensitive optical components, etc.) that greatly increase the complexity and cost of the system.

[0008] In view of the above, there is a need for a system and method for particle confinement that is simple to implement and avoids undesirable effects such as position drift due to optical phase fluctuations, crosstalk, and the Talbot effect. Summary of the Invention

[0009] The present disclosure overcomes the deficiencies of the prior art by providing a system and method for controlling particles using projected light.

[0010] In one aspect of the disclosure, a system for controlling particles using projected light is provided. The system includes a particle system configured to provide a plurality of particles and a light source configured to generate a light beam at a frequency shifted from an atomic resonance of the plurality of particles. The system also includes a beam filter disposed between the particle system and the plurality of particles, the beam filter including a first mask, a first lens, a second mask, and a second lens, the light source, the beam filter, and the particle system are disposed such that the light beam from the light source passes through the beam filter and is projected onto the plurality of particles to form a light pattern that controls the position of the particles in space.

[0011] In another aspect of the present disclosure, a method of controlling particles using projected light is provided. In some aspects, the method includes generating a light beam using a light source and directing the light beam to a beam filter including a first mask, a first lens, a second mask, and a second lens. The method also includes forming a light pattern using the beam filter and projecting the light pattern onto a plurality of particles to control the position of the plurality of particles in space.

[0012] These and other aspects and advantages of the present invention will become apparent from the following description. Reference is made in this specification to the accompanying drawings, which form a part hereof, illustrating preferred embodiments of the invention. However, such embodiments do not necessarily represent the full scope of the invention, and therefore the scope of the invention should be interpreted with reference to the claims and this specification. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a system according to an aspect of the present disclosure. [Figure 2A]FIG. 2 is a schematic diagram of an embodiment of a beam filter according to aspects of the present disclosure. [Figure 2B] FIG. 13 is a schematic diagram of another embodiment of a beam filter according to an aspect of the present disclosure. [Figure 3A] FIG. 1 illustrates a perspective view of an example mask according to aspects of the present disclosure. [Figure 3B] FIG. 13 is a perspective view of another example mask according to aspects of the present disclosure. [Figure 4A] FIG. 2 is a diagram of an example beam filter according to an aspect of the present disclosure. [Figure 4B] FIG. 13 is a diagram of another example beam filter according to an aspect of the present disclosure. [Figure 4C] FIG. 4C is a diagram of an example mask used in the beam filter shown in FIG. 4B. [Diagram 5] 1 is a graph comparing the intensity profiles for a Gaussian beam (IG) and an Airy-Gaussian beam (I2) resulting from uniform illumination of a circular aperture. [Figure 6] 1 is a graph comparing the on-axis intensity as a function of the axial coordinate z, calculated by Fresnel diffraction, for a Gaussian beam (IG), an Airy-Gaussian beam (IAG), a dark Airy-Gaussian beam (|1-EAG|2), and a dark Gaussian beam (|1-EG|2). [Figure 7] FIG. 13 is a diagram of yet another example beam filter according to aspects of the present disclosure. [Figure 8] 1 is a flow chart defining process steps according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Conventional particle trapping techniques generally rely on interference between mutually coherent light beams. This approach suffers from a number of drawbacks, including sensitivity to beam misalignment, light source phase drift, and phase noise. In contrast, the present inventors have discovered that projected light fields can be used to trap particles. As described in detail in U.S. Pat. No. 9,355,750, the entirety of which is incorporated herein by reference, projected light fields can be used to overcome the drawbacks of the prior art and provide many advantages. For example, particle trapping done using projected light fields can be scaled and can provide deeper trapping depths, without position or depth changes due to light source phase drift or noise. Furthermore, less energy is required per trap site, which can result in more sites for a given energy.

[0015] Recognizing practical considerations such as ease of implementation and cost, the present disclosure introduces a novel approach to trapping particles using optical fields. In particular, the present disclosure provides a simple and low-cost solution that improves performance over prior art techniques by improving trapping strength and particle localization. Furthermore, the present approach provides increased robustness and efficient use of light.

[0016] As will be understood from the following description, the present invention can be used to improve various technical fields. For example, the atomic particle arrays produced by the present disclosure can be part of the hardware configuration of a quantum computer or quantum computation system. In addition, atoms trapped using the methods herein can be used as atomic clocks or atomic sensors, and can also be used in quantum simulation applications. Other improved technical fields can include optomechanics and small sphere applications. For example, trapped particles (e.g., microspheres, nanospheres) can be used as probes to measure physical quantities or as laser sources for optical frequency combs.

[0017] 1, a schematic diagram of an example system 100 according to an aspect of the present disclosure is shown. System 100 may generally include a light source 102, a beam filter 104, and a particle system 106. System 100 may optionally include a controller 108 configured to communicate with and control light source 102, light filter 104, and / or particle system 106.

[0018] The light source 102 may include various hardware for generating light. In particular, the light source 102 may be configured to generate light having various frequencies, wavelengths, power levels, spatial profiles, temporal modulations (e.g., periodic or non-periodic), and the like. In some embodiments, the light source 102 may be configured to generate a light field with a frequency shifted from at least one atomic resonance. For example, the light source 102 may be configured to generate blue-detuned light or red-detuned light, and the amount of detuning may depend on the species of the particle (e.g., atomic species) being trapped. By way of example, the detuning may range from about 10 to about 100 nanometers.

[0019] In one embodiment, the light source 102 includes a laser that generates light having a wavelength in the range of about 500 nm to about 1500 nm, although other wavelengths are possible. In another embodiment, the light source 102 includes multiple lasers operating at multiple frequencies, with the frequency separation between the lasers configured to achieve a target coherence. The frequencies may be selected to achieve full coherence, partial coherence, or incoherence between the various light regions of the light pattern. In one non-limiting example, two frequencies may be utilized, and the wavelength difference may vary by up to about 100 nanometers, although other values ​​are possible. In this manner, the different components that form a particular light field may be configured to be mutually incoherent.

[0020] The beam filter 104, located downstream of the light source 102, is configured to control the light beam(s) generated by the light source 102. In particular, the beam filter 104 is configured to use the generated light to form a light pattern, which is projected onto various particles (e.g., neutral atoms) to trap the particles in space. Specifically referring to FIG. 2A, the beam filter 104 may include a first mask 202, a first lens 204, a second mask 206, and a second lens 208, and is configured such that the incident light 200 passes through the first mask 202, the first lens 204, the second mask 206, and the second lens 208 in sequence, and then exits the beam filter 104 to form a light pattern 210. In another variation, as shown in FIG. 2B, the beam filter 104 may further include a third mask 212 located between the first mask 202 and the first lens 202, and the third mask 212 may include a phase scrambling mask. The phase scrambling mask may include multiple scrambling regions, each of which conveys a phase shift to light passing through it. In some embodiments, the phase shifts provided by different phase scrambling regions are different from each other and are randomly distributed across the phase scrambling mask over 2π. To this end, different phase scrambling regions may include different dielectric properties or layers.

[0021] In some embodiments, the first mask 202 may have various transmissive (e.g., apertures) and reflective regions configured to generate a light pattern including light and dark regions. The light and dark regions are configured to confine the position of one or more particles to a desired pattern by light-induced trapping forces. As used herein, "light" refers to regions of light intensity maxima and "dark" refers to regions of light intensity minima. In some non-limiting examples, the light pattern may include one or more arrays of light spots or arrays of dark spots, respectively. For example, the light pattern may include an array of light spots or dark spots arranged in a one-dimensional (1D) or two-dimensional (2D) array. Other 1D and 2D arrays are also possible. For example, non-rectilinear grids such as parallelogram grids, triangular grids, or hexagonal grids, as well as configurations of light and dark regions may be created. Additionally, in some examples, the light pattern may include a 3D configuration including multiple 1D or 2D arrays of light and / or dark regions with various desired spatial separations therebetween.

[0022] In some embodiments, the first mask 202 of the beam filter 104 may be formed with a reflective surface 300 as shown in Figures 3A and 3B. The reflective surface 300 may include a substrate 302 (e.g., glass or other transparent substrate) coated with a reflective layer 304 having a predetermined reflectivity r. As shown in Figure 3A, the reflective layer 304 may cover a portion of the substrate 302 to form at least one aperture 306 through which light can pass. In this manner, one or more bright spots may be formed when light strikes the reflective surface 300. In some variations, the aperture 306 may extend all the way through the substrate 302. Alternatively, the reflective layer 304 may form a reflective region 308 on the substrate 302 to form at least one dark spot, as shown in Figure 3B. Although the apertures 306 in FIG. 3A and the reflective areas 308 in FIG. 3B are shown as circular, they may have a variety of other shapes (e.g., rectilinear, rectangular, square, elliptical and other regular or irregular shapes), number, size and spatial arrangement / spacing depending on the desired light pattern.

[0023] Referring again to FIG. 1, the particle system 106 may be configured to provide and control a multitude of particles. Specifically, the particle system 106 may include various materials, gases, and hardware configured to generate, transport, manipulate, and generally confine particles. For example, the particle system 106 may include a vacuum system and may include the ability to generate, transport, and confine particles within the vacuum system. In some non-limiting examples, the particles may include neutral atoms of any species, such as Rb, Cs, Ho, Sr, Tb, Ca, and the like, or combinations thereof. However, the systems and methods of the present invention are not limited to alkali or atomic particles, but may be applied to any particle or molecule suitable for optical confinement. In some embodiments, the particle system 106 may be configured with the ability to cool the particles to any desired temperature to facilitate trapping. For example, the particle system 106 may include a laser to cool the particles to a temperature in the range of 1-100 microkelvin, although other values ​​are possible. Alternatively, the light source 102 may be used for this purpose. In addition, the particle system 106 may include various optical elements to facilitate projecting the generated light field onto the particles therein.

[0024] In some embodiments, system 100 may include various other hardware and optical elements to direct, transmit, modify, focus, split, modulate, amplify the generated light field to achieve various shapes, sizes, profiles, orientations, polarizations, intensities, and any other desired light characteristics. For example, in a non-limiting example, system 100 may include a top-hat beam shaper configured to convert a Gaussian shaped beam emitted by a laser, for example, into a uniform intensity light beam with sharp edges. System 100 may also include other optical elements, such as various beam splitters, beam shapers, shapers, diffractive elements, refractive elements, diffraction gratings, mirrors, polarizers, modulators, etc. These optical elements may be positioned between light source 102 and beam filter 104 and / or after beam filter 104.

[0025] Additionally, system 100 may optionally include other capabilities, including hardware control or interrogation of quantum states of particles constructed and arranged according to the present disclosure. Such capabilities may facilitate applications including quantum computation and the like. These, along with other tasks, may optionally be performed by controller 108 shown in FIG. 1. For example, controller 108 may be configured to trigger light source 102 to generate light. Additionally or alternatively, controller 108 may be configured to control the operation of particle system 106 and its various components.

[0026] In some embodiments, the beam filter 104 of the system 100 may be configured to generate a light pattern using Fourier filtering or a "4f" optical arrangement. With particular reference to FIG. 4A, the beam filter 104 may include a first mask 402 having a circular aperture of radius a, a first lens 404 having a focal length f1, a second mask 406 having a circular aperture of radius b, and a second lens 408 having a focal length f2. As shown, the first mask 402 and the second mask 406 are located at a focal length f1 of the first lens 404. Furthermore, the second mask 406 is located at a focal length f2 of the second lens 408. When the beam filter 104 is uniformly illuminated, a portion of the input light 400 passes across the first aperture 402 located at the input plane and generates an Airy light pattern by the first lens 404 at a focal plane behind the first lens where the second mask 406 is located. The Airy light pattern is then filtered by a second mask 406 and the filtered Airy pattern is Fourier transformed by a second lens 408 to produce a light pattern 410 at the output plane. Using standard optical diffraction theory, the field at the output plane is given by:

[0027]

number

[0028] where A0 is the amplitude of the input light 400. The finite integral of the Bessel function in equation (1) can be expressed as a power series in b using the following equation:

[0029]

number

[0030] where 2F1 is the hypergeometric function. In some embodiments, the focal length and aperture of the second mask 406 can be selected as f1=f2=f and b=(f / ak)x1, where x1 is 3.8317, which is the first zero of J1. This selection corresponds to blocking the Airy ring outside the central lobe, so that the total power in the central lobe is the total power I0πa 2 (where I0 is the input intensity), so there is little power loss. With these choices, the output field can be expressed as a power series in ρ2 / a. The leading term is:

[0031]

number

[0032] The resulting light pattern is called an Airy-Gaussian (AG) beam because the beam filter 104 filters the Airy light pattern so that its intensity has an approximately Gaussian shape. As shown in Figure 5, the AG beam is a quadratic function of ρ2 near the origin. Matching the quadratic term with that of the Gaussian intensity profile gives

number

[0033] The above Fourier filtering approach to beam shaping can be easily extended to create an array of Gaussian beams. With specific reference to FIG. 4B, in some embodiments, the first mask 402 of the beam filter 104 may include an array of apertures arranged on a two-dimensional grid with spacing d. The light field transmitted through each aperture of the first mask 402 has the form given by equation (1) and is proportional to the position −ρ in the output plane. ij where ρ ij is the position of the ijth aperture relative to the axis 412 of the first mask 402. When the spacing satisfies approximately the relationship d>3a, interference between adjacent beams is negligible. In some embodiments, the array of bright spots at the output plane can be re-imaged with any desired magnification to obtain d outAn array of beams can be created with a spacing given by = (df2 / f1) × M, where M is the magnification of the reimaging optics.

[0034] The efficiency of array creation is ε=I t / I d It can be defined as follows: I t is the peak intensity of the output beam, and I d =P / d 2 is the input intensity with power P per d×d unit cell. Then the peak intensity can be expressed as

[0035]

number

[0036] Therefore, ε=1.66, independent of the value of a.

[0037] In some applications, such as quantum computation, an array of dark spots with a Gaussian profile may be desired to trap particles at local minima of light intensity. Thus, by combining a wide input beam, i.e. a plane wave, with a bright Gaussian beam with equal amplitude and π phase difference, dark spots can be created by creating a field null from destructive interference. To do so, the first mask 402 of the beam filter 104 shown in FIG. 4B can be replaced with a modified first mask 402′, as shown in FIG. 4C, having an array of reflective spots with a radius a or otherwise completely transparent. In some embodiments, the modified first mask 402′ may be formed using a transparent substrate and an array of partially or fully reflective regions (e.g., circular spots), as described with reference to FIG. 3B.

[0038] With particular reference to FIG. 4B, the light field transmitted through the modified first mask 402′ can be expressed as:

[0039]

number

[0040] In the formula, E d is the amplitude of the plane wave incident on the modified first mask 402′, and E ij is the light field passing through the ijth aperture, and r is the reflectivity of each spot. A plane wave, which may be much wider than the field of a single aperture, will be completely transmitted through the modified first mask 402' and the beam filter 104. Thus, the field at the output plane is:

[0041]

number

[0042] In the formula, E 2,ij is the position in the output plane -ρ ij (1) centered at . If we choose r = 1 / √1.66 = 0.78, we find a field of -ρ surrounded by an intensity pattern with a Gaussian profile. ij Then, the efficiency is

number

[0043] This efficiency is somewhat lower than that obtained for the array of bright spots as described above. Nevertheless, both efficiencies compare favorably with conventional methods. Specifically, the dark spots previously created with Gaussian beam arrays using diffractive optical elements have ε≦0.51, and the line arrays have ε≦0.97. In contrast, the present Fourier filtering approach yields a significantly better efficiency than the line arrays, since the diffractive multi-spot gratings used to prepare such arrays have an efficiency of approximately 0.75. One reason for this is that beam shapers that provide uniform illumination (e.g., top-hat beam shapers) can have an efficiency of nearly 100%.

[0044] The important parameters in particle or atom trapping are I t The trap depth and spatial localization are proportional to . When the trapped particle has small kinetic energy compared to the depth of the trapping potential, the localization is dominated by quadratic variations in intensity near the trap center. For a bright trap that localizes the particle near the intensity maximum, the trapping potential can be expressed as

[0045]

number

[0046] where ρ is the radial coordinate and z is the axial coordinate along the trapping axis. For a particle with kinetic temperature T, the Virial theorem states:

[0047]

number

[0048] In the formula, k B is the Boltzmann constant. Therefore, the standard deviation of the particle positions is

[0049]

number

[0050] Waist parameter w G For an ideal Gaussian beam with and optical wavelength λ:

[0051]

number

[0052] Therefore, equation (10) can be expressed as:

[0053]

number

[0054] For an Airy-Gaussian beam, w G =0.974a, and the position deviation is:

[0055]

number

[0056] Using a=d / 3, the location coefficient can be expressed as follows:

[0057]

number

[0058] Equations (12) and (14) give the position spread for a bright light trap. For a dark light trap made by interfering a Gaussian beam with a plane wave, the axial profile far from the origin differs from that of the bright trap due to the variation of the field phase with z given by

[0059]

number

[0060] This is shown in Figure 5. Note that the axial profiles are slightly different for the Airy-Gaussian and Gaussian beams. Nevertheless, the main quadratic terms remain unchanged, so the localization parameters are still given by equations (12) and (14). We can compare these results with the traditional approach for Gaussian line arrays, where

number

number

[0061] The Fourier filtering techniques described herein, whether used to create an array of light or dark traps, may result in the formation of multiple trap planes due to the Talbot effect. In cases where such planes are not desired, a variation on the configuration of FIG. 4B may be utilized, as shown in FIG. 7. Specifically, a phase scrambling mask 414 may be placed between the first mask 402 and the first lens 404. As shown, the phase scrambling mask 414 scrambles ρ ij , each scrambling region may include an array of scrambling regions 416 positioned at a phase shift φ ij and provides complete transmission of light therethrough. In some embodiments, the phase shift φ of each scrambling region 416 ij may vary between 0 and 2π and may be randomly distributed across the phase scrambling mask 414.

[0062] 8, steps of a process 800 for controlling particles using projected light in accordance with the present disclosure are provided. In some embodiments, the steps of process 800 may be performed using the systems described herein as well as other suitable systems or devices.

[0063] Process 800 may begin with generating a light beam using a light source at process block 802. As described, the light beam generated by the light source may have a variety of characteristics including various frequencies, wavelengths, power levels, spatial profiles, temporal modulations, etc. In some embodiments, the light beam may have a frequency that is shifted from at least one atomic resonance of the particle to be trapped.

[0064] The light beam may then be directed to a beam filter, as indicated by process block 804. In aspects of the present disclosure, the beam filter may include a first mask, a first lens, a second mask, and a second lens. In some variations, the beam filter may further include a third mask disposed between the first mask and the first lens, and the third mask may include a phase scrambling mask. As indicated by process block 806, the beam filter may be configured such that the light beam passes sequentially through the first mask, optionally the third mask, the first lens, the second mask, and the second lens, followed by the beam filter to form the light pattern. As described, the light pattern may have various configurations depending on the particular application.

[0065] A light pattern may then be projected onto a plurality of particles (e.g., atomic particles) to control the position of the plurality of particles in space, as indicated by process block 808. To this end, the particles may be provided by a particle system configured to generate and confine the particles to a particular volume or general location in space. As described, the provided particles may be held in a vacuum and cooled to a temperature suitable for optical trapping.

[0066] While the invention has been described in terms of one or more preferred embodiments, it is to be understood that many equivalents, alternatives, variations, and modifications, aside from what is expressly stated, are possible and are within the scope of the invention.

Claims

1. 1. A system for controlling particles using projected light, comprising: a particle system configured to provide a plurality of particles; a light source configured to generate a light beam at a frequency shifted from an atomic resonance of the plurality of particles; a beam filter disposed between the particle system and the plurality of particles, the beam filter including a first mask, a first lens, a second mask, and a second lens; the first mask includes a reflective surface formed using a substrate coated with a reflective layer; the reflective layer includes at least one transmissive region that produces at least one bright region in a light pattern; the first mask, the first lens, the second mask, and the second lens are arranged such that a light beam passes through them in sequence; The light source, the beam filter and the particle system are arranged such that a light beam from the light source passes through the beam filter and is projected onto the plurality of particles to form the light pattern that controls the position of the particles in space.

2. the first mask is positioned a first focal distance away from the first lens; The system of claim 1 , wherein the second mask is positioned the first focal distance away from the first lens and a second focal distance away from the second lens.

3. The system of claim 1 , wherein the reflective layer includes at least one reflective region that creates at least one dark region in the light pattern.

4. The system of claim 1 , wherein the beam filter further comprises a third mask disposed between the first mask and the first lens.

5. 5. The system of claim 4, wherein the third mask is a phase scrambling mask having phase scrambling regions configured to impart a phase shift to light passing therethrough.

6. The system of claim 5 , wherein the phase shifts imparted by different phase-scrambling regions are different from each other and randomly distributed across the phase-scrambling mask.

7. The system of claim 1 , wherein the first mask comprises a plurality of apertures in a one-dimensional (1D) or two-dimensional (2D) array.

8. The system of claim 1 , wherein the plurality of particles comprises neutral atoms.

9. The system of claim 1 , wherein the light beam has a frequency shifted from the atomic resonance to achieve blue-detuning or red-detuning.

10. The system of claim 1 , wherein the beam filter is further configured to convert a Gaussian or near-Gaussian beam into a beam having a uniform intensity profile.

11. A method of controlling particles using projected light generating a light beam using a light source; directing the light beam to a beam filter including a first mask, a first lens, a second mask, and a second lens; forming a light pattern using the beam filter; projecting a light pattern onto a plurality of particles to control positions of the plurality of particles in space; the first mask includes a reflective surface formed using a substrate coated with a reflective layer; the reflective layer includes at least one transmissive region that produces at least one bright region in the light pattern; The method, wherein the first mask, the first lens, the second mask and the second lens are positioned such that the light beam passes through them in sequence.

12. the first mask is positioned a first focal distance away from the first lens; The method of claim 11 , wherein the second mask is positioned the first focal distance away from the first lens and a second focal distance away from the second lens.

13. The method of claim 11 , wherein the reflective layer includes at least one reflective region that creates at least one dark region in the light pattern.

14. The method of claim 11 , wherein the beam filter further comprises a third mask disposed between the first mask and the first lens.

15. 15. The method of claim 14, wherein the third mask is a phase scrambling mask having phase scrambling regions configured to impart a phase shift to light passing therethrough.

Images