Pulsed laser modification of quantum particle cells

Abstract

A pulsed laser applies short (e.g., less than 10 picosecond) pulses to modify ultra-high vacuum (UHV) cells with quantum particles (e.g., alkali and alkaline earth metal atoms) to bond, ablate, and / or chemically modify the vacuum-facing surfaces of the cells. The pulses are generated outside the cells and transmitted through the vacuum boundary walls. In one example, one vacuum boundary wall is first contact bonded to the other vacuum boundary wall at a relatively low temperature (less than 200° C.) sufficient to form a temporary hermetic seal. Pulsed laser bonding is used to strengthen the contact bond, correct defects, and generally increase the robustness of the seal. The pulses provide high peak power to ensure a strong bond, but low total thermal budget to avoid thermal damage to nearby cell components and to limit the absorption and adsorption of quantum particles into the cell walls.

Description

CROSS-REFERENCE TO OTHER APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 150,440, filed February 17, 2021, entitled "VACUUM CELL MANUFACTURING USING PULSED LASERS," and U.S. Patent Application No. 17 / 493,155, filed October 04, 2021, entitled "PULSED-LASER MODIFICATION OF QUANTUM-PARTICLE CELLS," both of which are incorporated herein by reference for all purposes.

[0002] Quantum particle cells are designed to hold quantum state carriers (e.g., alkali and alkaline earth metal atoms) under ultra-high vacuum (UHV) conditions, where their quantum states are then controlled and monitored using electromagnetic radiation (EMR) that accesses the carriers through windows and / or walls of the cell. In addition to containing quantum particles, quantum particle cells can include components for directing the particles and / or EMR, and components for establishing, maintaining, and restoring UHV conditions.

[0003] If quantum particle cells are more compact, quantum systems incorporating the cells can be more compact and more economical. Furthermore, cost savings can be achieved since less expensive quantum particle raw materials may be required with more compact cells. However, the manufacture of more compact cells faces new challenges. For example, temperatures generated during manufacture can adversely affect various cell components and drive quantum particles toward the cell walls. In larger cells, heat can be manageable because affected entities can be protected by temperature gradients over longer distances. In more compact cells, there is less space available for heat to decay before reaching heat-sensitive components. Also, some manufacturing processes release oxygen that can passivate particle sources and getters, reducing their functionality. Thus, quantum particle cell manufacturing requires some innovation to address the challenges posed by more compact quantum particle cells. [Brief description of the drawings]

[0004] [Figure 1] 1 is a flow chart of a quantum particle cell fabrication process.

[0005] [Diagram 2] FIG. 2 is a schematic diagram illustrating a manufacturing system for the quantum particle cell fabricated in FIG. 1.

[0006] [Diagram 3] 1A-1D illustrate various stages in the fabrication of multiple quantum particle cells.

[0007] [Figure 4] 4 illustrates the quantum particle cell of FIG. 3 after a top cover has been bonded in place over the quantum particle cell of FIG. 3 and then reinforced with pulsed laser bonding.

[0008] [Diagram 5] 5 illustrates the quantum particle cells and covers of FIG. 4 after the covers have been bonded to the individual quantum particle cells using a pulsed laser.

[0009] [Figure 6] Diagram of the multi-chamber quantum particle cell with the location of the pulsed laser bond indicated.

[0010] [Figure 7] Side and top views of the quantum particle cell structure.

[0011] [Figure 8] 8 is an exploded view and a top view of the particle cell structure of FIG. 7 with an indium tin oxide coating on the top and bottom covers.

[0012] [Figure 9] 1 is a schematic diagram illustrating a quantum particle cell manufacturing system including an ultra-high vacuum station with in-vacuum laser beam steering.

[0013] [Figure 10] FIG. 1 is a schematic diagram showing a quantum particle cell fabrication system with an ultra-high vacuum station and external laser beam steering.

[0014] [Figure 11] 1 is a schematic diagram illustrating a quantum particle cell manufacturing system with a movable laser system.

[0015] [Figure 12A] FIG. 1 shows pulsed laser ablation of a square cell. [Figure 12B] FIG. 1 shows pulsed laser ablation of a square cell.

[0016] [Figure 13] 1 is a black and white photograph of two quantum particle cells fabricated in accordance with the present invention.

[0017] [Figure 14] FIG. 1 is a black and white photograph of a quantum particle cell having ports that allow for the entry of source material and / or are utilized for the removal of material during maintenance cycles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention provides pulsed laser modification of quantum particle cells. The lasers of interest herein can deliver high peak intensity over a short period of time (e.g., less than 1 nanosecond (ns) to less than 1 femtosecond (fs)) to a small area such that the total amount of heat delivered per pulse is fairly small. As a result, the thermal gradient drops sharply to avoid damage to nearby heat-sensitive components. Another advantage of lasers is that they can be focused through the typically transparent walls of quantum particle cells, allowing modification of the inner surface of the sealed cell, thus enabling late-stage and post-manufacturing repair of compact quantum particle cells (such as cells with sub-millimeter vacuum volumes).

[0019] A quantum particle cell fabrication process 100 is shown in FIG. 1. The desired end product of process 100 is rubidium-87 ( 87 The quantum particles are typically tightly sealed vapor cells filled with quantum particles such as Rb. Alternatively, the cells may contain quantum particles in liquid or solid form, and the quantum particles may be 87 The particles may be isotopes of Rb, other atomic species, and / or other molecular entities (e.g., ions, polyatomic molecules). The top left and top right of Figure 1 show the quantum particle cell body 102 with a top cover 104 not yet attached. The particle cell body 102 comprises a bottom cover (i.e., base 106) and four side walls 108.

[0020] In step 110, quantum particles or a quantum particle source are loaded into the body, and then a cover is contact bonded to the body to seal the quantum particle cell. The quantum particles may be loaded in vapor, liquid, or solid form. In some cases, the quantum particles or reversible compounds thereof may be stored in a glass ampoule or carbon host for later release. If not promoted, contact bonding may take weeks or months to achieve the desired bond strength. More rapid bonding may be achieved using methods such as electrically promoted contact bonding or chemically promoted contact bonding (e.g., hydroxide bonding). When the surfaces to be bonded are glass and silicon, anodic bonding may be utilized. Pulsed laser bonding 120 may be applied to assist or strengthen any such bonding. Laser pulses may be applied along a closed path to form a complete seal. Adjacent laser bonds may overlap such that there are no gaps in the laser bonded seal. In an alternative embodiment, contact bonding is omitted and laser bonding is utilized only for the hermetic seal.

[0021] A quantum particle cell manufacturing system 200 is shown in Figure 2 and includes a controller 202, a laser system 204, and an ultra-high vacuum (UHV) station 206. The UHV station 206 includes a rectangular glass enclosure 208, and tools, optics, electronics, and a power supply 210. As shown in Figure 2, UHV Station 206 houses the quantum particle cell 124 during its manufacture. The laser system 204 accesses the cell 124 through a glass enclosure 208. One advantage of manufacturing in a UHV environment is that the desired UHV is automatically achieved in the manufactured cell. Another advantage is that there are fewer contaminants that can degrade the cell 124 during manufacture.

[0022] In one embodiment, cell fabrication is completed within the housing 208. However, in the illustrated embodiment, the contact bonded cell is removed from the UHV environment prior to laser bonding / strengthening / annealing. The cover is pulled towards the cell body by external pressure as laser bonding completes the cell fabrication. The advantage of performing laser bonding outside of the housing 208 is that there is one less layer of (potentially inwardly bowed) glass to penetrate, resulting in reduced power loss, beam quality, and accuracy.

[0023] Economies of scale can be achieved by fabricating multiple cells at once. As shown in FIG. 3, cell arrays 302 are disposed on and contact-bonded to a base 304 to define inter-array gaps 306. Because they are formed before components and / or quantum particles are introduced, anodic bonds can be formed at high temperatures (e.g., 300° C.) or by other convenient / suitable means to achieve strong bonds in a relatively short time. Each array 302 comprises a pair of array walls 308 and a sidewall 310 extending between the array walls and defining cells 312 and inter-cell gaps 314. In some embodiments, a peripheral rim 316 is bonded to the base 304. The resulting structure can be inserted into a UHV environment (such as that shown in FIG. 2). Depending on the embodiment, components and / or quantum particles can be inserted into the cells before or after the assembly is inserted into the UHV environment.

[0024] While the assembly is in the UHV environment, a glass cover 402 may be contact bonded to the rim 316 and / or array 302, as shown in FIG. 4. The bonding may be unfacilitated contact bonding, thermally facilitated contact bonding, and / or electrically facilitated contact bonding. However, any heating may need to be limited to avoid issues related to the cell components or quantum particles or quantum particle sources. The result may be a hermetic seal, but may not be robust enough to withstand subsequent dicing to separate the cells.

[0025] The cover band may be sufficient to allow the covered assembly to be moved to a laser station for laser stitching. In some embodiments, the laser stitching may be performed while the assembly is in the UHV environment. In some such embodiments, contact bonding of the cover may be omitted. However, without the walls of the UHV environment in the laser beam path, it may be easier to focus the laser beam to the correct depth where the bottom surface of the cover contacts the top surface of the cell and / or rim.

[0026] At the laser station, the cover may be laser stitched to hermetically and robustly seal the cells, and the resulting pulsed laser bond 502 is shown in FIG. 5. The individual bonds may overlap to ensure a continuous seal, or may be spaced apart to reduce potential stress / strain failures and allow gaps to effectively become reinforced contact bonds in place with adjacent laser bonds. The overlapping bonds do not need to be made in sequence. Instead, the individual bonds (one bond per pulse) may be made out of sequence to allow each pulse bond to cool before the next bond is formed. In an alternative embodiment where the cells are hermetically sealed in FIG. 5 but the gaps are only bonded at the sidewalls and not bonded along the array walls, the pulse bonds are also made all along the array walls.

[0027] As shown in Figure 6, the microchannel UHV cell 600 includes a body 602, a bottom cover 604, a top cover (not shown), and an ion pump 608. The body 602 is formed from a monolithic slab of material such as silicon or glass by removing material to define the chambers and inter-chamber channels. The chambers include a source chamber 610, a magneto-optical trap (MOT) chamber 612, and an ion pump chamber (blocked by an ion pump 606). The inter-chamber channels include a source-to-MOT channel 614, a MOT-to-pump channel 616, and a source-to-pump channel 618 (which is gated as it is only open during maintenance procedures).

[0028] The cover may be bonded to the raised area of ​​the body 602 using, for example, contact bonding or hydroxide bonding. In variations where the body is silicon and the top cover is glass, anodic bonding may be used. The strongest bonds may be made using thermally accelerated contact bonding or anodic bonding at high temperatures (e.g., about 300° C.). However, such high temperatures may damage internal components such as the source and getter in the source chamber and the atom chip in the MOT chamber. Anodic bonding also releases oxygen, and the amount of oxygen released is a function of temperature. Oxygen may passivate the alkali metal source and getter materials, reducing their usefulness.

[0029] To avoid such damage, the bonding temperature may be limited to the laser maximum temperature (e.g., 150° C.). An additional benefit of lower temperatures is that they relax coefficient of thermal expansion (CTE) constraints on the cover, for example, allowing the use of cover materials with lower helium permeability. On the other hand, lower temperature bonds may be weaker and more susceptible to unintentional delamination. The relatively weak anodic bonds may be strengthened or completed with laser pulse bonded joints 620. Alternatively, the laser pulse bonds may be overlapped or at least closely spaced as necessary to form hermetic bonds in place of contact or anodic bonds.

[0030] As shown in Figure 7, quantum particle cell 700 comprises a top cover 702 and a bottom cover 704 sandwiching a sidewall structure 706. Note that top cover 702 and bottom cover 704 extend beyond the perimeter of sidewall structure 706. This leaves room for external contacts for electrical feedthroughs. Top cover 702 and bottom cover 704 have anti-reflective coatings 712 and 714 and indium tin oxide (ITO) coatings 716 and 718 on vacuum-facing surfaces 720 and 722.

[0031] ITO is a transparent conductive coating into which a pulsed laser can write a resistive area (e.g., a resistive area of ​​100 Ω-cm). For example, a pulsed laser system 204 may be used to write a resistive strip 802 into an ITO coating 718 on a base 704, as shown in FIG. 8. As a result, the ITO coating 718 is divided into four conductive quadrants. Each quadrant comprises a field plate internal to the cell 700 and a contact 806 electrically connected to the field plate to allow the potential on the field plate to be controlled by an external potential source. (As used herein, the contacts 806 are on the vacuum-facing surface even though the portion of the surface on which they rest faces the atmosphere rather than the vacuum). Corresponding patterning of the ITO coating 716 of the top cover 702 results in four further field plates and contacts. In total, eight field plates and corresponding contacts enable three-dimensional electric field control within quantum particle cell 700, as taught in U.S. patent application Ser. No. 17 / 340,039, filed June 6, 2021, by Mark Saffman, Thomas William Noel, and Steven Michael Hughes.

[0032] The electric field gradient achievable with a resistive strip is limited by the resistivity of the resistive strip. Steeper gradients may be achieved by removing the ITO material rather than simply converting it. However, doing so changes the coating thickness and compromises the hermetic seal where the ITO material extends under or over the sidewall structure. Patterned deposition of insulating material is available to replace the thickness lost by the removal of the ITO. However, this deposition must be performed before the cell assembly is complete and may need to be impractically thin.

[0033] The main advantage of pulsed laser conversion of ITO is that it can be performed after cell assembly is complete. This allows for a split manufacturing model where ITO coated blanks are prepared and stored in inventory. As a result, the blanks can have custom patterns of conductive and resistive materials written by the pulsed laser on demand. Patterning is performed one focal point at a time and can raster the pattern diffractively, holographically, interferometrically, or by other means using ultrafast pulses. The change in conductivity can be the result of annealing, diffusion, oxidation, gas reaction, or ablation.

[0034] The embodiments utilize picosecond and / or femtosecond lasers for the manufacture and repair of vacuum chambers or cells, thus enabling cold atom and quantum vacuum systems. The embodiments provide pulsed laser in-vacuum bonding of similar and / or dissimilar materials, such as materials with different coefficients of thermal expansion (CTE). Pulsed laser bonding thus allows for the utilization of a wider range of materials, for example, materials with lower helium permeability can be utilized. (Helium permeability is an increasing concern as the surface area to volume ratio increases as quantum particle cells become more compact, especially where active pumping is not desired). The utilization of pulsed lasers allows the bonding of materials with different CTEs to be done at low temperatures to avoid failures due to thermal cycling. All such in-vacuum bonding may be performed after vacuum processing to prevent material breakage due to CTEs where exposure to water or heat or other bonding processes or their by-products would destroy the components, while localized heating of the glass or sealing material allows for the protection of sensitive internal components. Pulsed laser bonding in vacuum can be used in conjunction with, or instead of, low temperature anodic bonding (e.g., silicon to glass) where exposure to oxygen resulting from anodic bonding can cause deleterious reactions to the cell or its contents.

[0035] Pulsed laser bonding can be used to complete or strengthen other types of bonds (anodic bonds, contact bonds, etc.) that may be incomplete or have failed partial bonds. Pulsed laser bonding can be used to help widen and complete the perimeter of a partial bond by pulling the bond over the failed area or even partially machining / vaporizing / ablation / eroding / removing trapped obstructions prior to or during the bond repair.

[0036] Pulsed lasers can also be used to repair breaks. Atomic tips can cause breaks and other non-hermetic anomalies, especially near material transitions (e.g., glass-silicon, etc.). Pulsed laser bonding can be used to rewet, fuse, bond, and seal such defects. Bonded cells (e.g., glass cells) can break from residual stresses resulting from bonding, etc., after use or after unused storage. Such breaks can be sealed with a local bond as if the break was an incomplete bond, and laser bonding is used to extend the seal over the nearly conformal break, with or without glass filler. In effect, this can be a repair service or recycling effort. Laser bonding can be used to bond cells that are partially unbonded and / or broken. The break can be repaired and the bond can be finished, or the break can be heated during bonding to allow for deformation and completion of the bond (e.g., anodic bonding). For non-optically transparent materials such as silicon, ultrafast lasers at wavelengths through which the material is sufficiently transparent (eg, micron (μm) wavelengths for silicon) can be used for bonding or damage repair.

[0037] Pulsed lasers can be utilized, for example, to separate or fix components of microelectromechanical systems (MEMS), e.g., to release MEMS-like structures that are intended to move freely. Such structures can be released from fixed connections, sprues, supporting frameworks, etc., by ablation or induced fracturing / cutting. The constraining structures can be intentional, with laser ablation being analogous to a final release or lift-off procedure. Alternatively, the contact point may have been accidental, in which case the UHV-cleaned parts naturally stick, and laser release is used to overcome stiction. Pulsed lasers can be utilized to pre-treat surfaces that may be prone to stiction, by partially ablating / eroding or altering surface features or activations to reduce the likelihood of stiction. Alternatively, pulsed lasers can be utilized to apply a laser ablation or laser ablation to opposing surfaces, e.g., to the surfaces of the stiction-preventing lasers ... ComplementaryIt may be used to increase friction by creating friction features, and by adjusting the power and spot size it can also induce bonding or fusing by locally melting materials and using oxides or plating on their surfaces to lock them in place.

[0038] Pulsed lasers can be utilized to initiate auto-singulation in arrays of laminated structures (such as vapor cells). Pulsed lasers may be used to initiate fractures in potentially fragile materials (such as intentionally stressed silicon-glass bonded pairs) to cause auto-singulation, particularly for arrays of vapor cells that are fabricated from a single large material substrate or assembly, but that are ultimately intended to become individual, distinct components.

[0039] A pulsed laser may be used to stitch cut or split holes in cells for repair or salvage, utilizing stresses within the cell to "pop out" the cut hole in the glass / silicon etc., allowing the port to be cut without impurity cutting fluid or debris destroying the cell. During the cutting operation, the shape is selected to encourage self-separation of the released plug, minimizing material that is ablated to contaminate the inside of the vacuum chamber. After post-cleaning and internal repair operations, the surface is left sufficiently flat for a conformal cap to be bonded over the port (conical / tapered port). Bonding may be contact bonding, anodic bonding, or laser bonding.

[0040] The singulation cut / split may be selected to take advantage of residual stresses, particularly from the anodically bonded parts on the glass, such that the stresses aid in the singulation / singulation process of the cut plug, such as by cutting a conical section tightly along the circumference of a circular mating silicon joint. To facilitate plug singulation, a prestressor material may be bonded to the plug. Such a material may be as simple as a contact-bonded, anodically bonded, or laser bonded disk-shaped or other shape of silicon or other material with a known CTE significantly different than the native material. After singulation cutting of the vacuum wall material after bonding of the stressor plate, the CTE stresses may be increased by applying direct heating or cooling, such as thermal contact, radiation absorption, acoustic energy, resistance, air jets, coolant exposure, etc.

[0041] Pulsed lasers can be used for pre-tacking bonding. For example, anodically bonded parts can be pre-taked when the temperature cannot be measured internally without UHV. The bond can then be re-formed with anodically bonded during vacuum processing. Delicate bonded parts can be pre-taked with a pulsed laser at the internal seam to form a weak hermetic seal. The weak seal can then be reinforced with capillary application of a silicate solution, hydroxide solution, sol-gel, or miscible / flowable bonding agent that may be more robust or offer other advantages over laser bonding.

[0042] During anodic or contact bonding, if the bond is imperfect due to scratches, dirt, or defects, laser bonding can be used to seal the cell by pulling the completed bond area over the imperfect area. When a small scratch or defect causes a potential pseudo-leak (an extremely poorly conductive path to a narrow trapped or near-trapped reservoir), laser bonding can be used to block the path and seal the pocket / scratch. Alternatively, a pulsed laser can be used to pull a closed bond over the pocket / scratch to eliminate the possibility of a pseudo-leak. A pulsed laser can be used to create a controlled helium or other leak by forming a laser-induced bond across a controlled, very narrow bond width to utilize the transmission through the small seam as a controlled diffusion "membrane."

[0043] Pulsed lasers can be used for targeted annealing. For example, annealing can include locally stitching high stress fixtures found by polarizers or other stress detection means to normalize or equalize or relieve stresses with the aim of preventing future defects. Stress reduction can be performed by selective application of a focused pulsed laser, or can be achieved by partially defocusing or decohering the pulses to enhance localized thermal effects in a controlled manner. Repeated pulses in the same area with lower effective power can aid in localized annealing. Alternatively, pulses near high stress areas, especially repeated pulses, can be used to create controlled, terminating fractures (such as domes, bubbles, or induced fractures) with the aim of relieving stresses without compromising the hermetic seal.

[0044] Pulsed lasers can be used to locally "stitch anneal" the surfaces of machined parts at internal corners where failure is predicted. It can be advantageous to induce stress around high stress areas rather than in the interior to help normalize stress gradients. Pulses (e.g., low power or diffuse / defocused pulses in, near, or opposite high stress areas) balance the stresses and reduce the likelihood of failure. Pulses (e.g., low power or diffuse / defocused pulses) can be used on the material while heating it locally with a continuous wave (CW) or nanosecond-millisecond laser / energy source, or globally with a hotplate or oven to improve bonding and stress properties. Localized heating with a laser can induce local expansion to improve contact or may only provide annealing during bonding.

[0045] If an optical device or component is held by a material, the laser pulses can be used to locally heat, deform, stress / relax, ablate, etc., to adjust small movements for precise alignment or tuning purposes, such as resonators or precision beam steering optical mounts. For resonant structures, pulsed lasers can adjust the index of refraction or micromechanical alignment by deforming, stressing, annealing, or ablating stressed surfaces for fine cavity tuning. Pulsed lasers can also be used to write waveguide structures as part of the walls of a vacuum chamber or to fine-tune waveguide structures already built into a vacuum chamber. Pulsed lasers can be used to locally deform optics (such as mirrors) directly below a reflective surface in vacuum to locally and precisely deform the wavefront, similar to adaptive optics. Pulsed lasers can be used to locally adjust the wavefront error of a window or lens by microscale refractive index changes or by inducing diffractive structures.

[0046] Pulsed lasers can be used to machine holes in uniform coatings. Pulsed lasers can be used to control light scattering in vacuum cells by absorbing in gradient index structures or forming gradient index structures on areas or walls with unwanted incident light from partial reflection, diffraction, or scattering to help selectively control the scattering angle for tightly controlled geometric surface structures. They can be used to effectively create spatial arrays of altered AR or HR effects by intentionally degrading anti-reflective (AR), (highly reflective) HR, conductive coatings before or after installation in a vacuum chamber by locally ablating the coating or optically changing its properties. This may be done to increase light scattering, adjust reflectivity or transmittance in fine-tuned optical systems, or adjust the sharpness of optical transitions at coating edges or cracks in the coating, etc., with the goal of minimizing diffraction effects.

[0047] Pulsed lasers can be utilized to purposefully construct effective AR surfaces through gradient index structures, particularly at sites of damaged AR coatings, with the goal of minimizing the effects of damage. The structures can be tailored to geometrically control scattering in specific directions of interest due to the geometry of the optical region of the vacuum cell. Pulsed lasers can be utilized to tailor the permeability of passivation or barrier coatings to increase transmission through the barrier, such as for controlled helium leakage from an encapsulated / barrier / passivated reservoir or partitioning of alkali or alkaline earth or other metals. Such barriered reservoirs may be initially intended to allow high temperature vacuum processing or to improve ease of handling during assembly and manufacturing, but the barrier later impedes operation of the vacuum chamber in other ways.

[0048] Pulsed lasers can blast protective oxides on strontium or other alkalis that may be present during air or atmospheric assembly but blasted / cleaved open during vacuum processing after sealing, or that may have been intentionally or accidentally coated with a metal or other barrier coating that has been sputtered, vaporized, etc. Pulsed lasers can be utilized to intentionally ablate and generate particles that are electrostatically or mechanically trapped to increase effective pumping speed or capability by dramatically increasing the surface area of ​​the material where such attribute is surface area dependent.

[0049] Pulsed lasers can be used to write gratings into channel cells or other vacuum cells. Pulsed lasers can be used to write custom gratings on the inner walls of a vacuum chamber before, during, or after assembly. Gratings can be written into silicon, metal, or other structures, transparent or opaque. Pulsed lasers can be used to help bond glass that may have custom gratings that cannot be bonded by normal wet or high temperature means due to the coating or material type. For example, pulsed lasers can allow bonding onto etched topography. Sealing gaps can be filled with a filler material and fused using a pulsed laser.

[0050] Pulsed lasers can write electrical structures into thin films deposited on glass or laminated into glass laminate structures in two or three dimensions that are utilized in vacuum chambers or as part of the vacuum chamber walls. Conductive films may be exposed to vacuum or atmosphere or may be coated with insulators or other coatings (such as nitrides or oxides). Structures may be modified after assembly and vacuum processing for tuning or problem solving. For example, pre-patterned conductor traces such as atom tips or plating on top of stacks under vacuum walls or oxide coatings that may cause shorts due to alkali penetration into gaps in insulators, dendritic growth, gold migration, dust deposition, or other types of unintended conductive shorts may be burned off / ablated / or otherwise micromachined away by laser pulses at the surface or at targeted depths. Pulses may be extended and defocused to enhance heating as a targeted thermal effect aid for short mitigation, such as to help locally reflow small gold bumps or promote selective ion migration, especially in the presence of strong electrical potentials.

[0051] Pulsed lasers can target and "destroy" or move through precise momentum impulses for ablation of dust particles at sensitive locations on ion traps or atom chips, etc. Pulsed lasers can be utilized for black silicon surface formation by targeting oxides for etching or direct ablation of black structures in glass, silicon, metals, or other materials. Pulsed lasers can operate through thin silicon at near infrared wavelengths (e.g., 1064 nanometers (nm)) and far infrared wavelengths (e.g., 1550 nm).

[0052] A pulsed laser can be used in conjunction with hydroxide or silicon / silica / silicate solutions to repair seams, where the laser is used to make the material a bit more homogenous. Microleaks can be filled with silicates, silica nanoparticles, sol-gels, or other glasses or glass precursors such as silicon nanoparticles, much like filling a hole with gravel, and then the laser can be locally "melted" to fill any gaps that may not be sealable by other means.

[0053] As shown in FIG. 9, a quantum particle cell manufacturing system 900 includes a UHV station 902 and a laser system 904 for manufacturing a quantum particle cell 906. The laser system 904 includes a pair of controllable mirrors 908 disposed within the UHV station 902 and used to steer a beam generated by the laser system 904. The UHV station 902 includes a top cover 910, which is shown bowed due to the pressure difference between high ambient pressure and low UHV pressure. The UHV station 902 further includes a means for moving the quantum particle cell 906 in three dimensions within the UHV station 902, as indicated by arrows 912. In an alternative embodiment shown in FIG. 10, a quantum particle manufacturing system 1000 includes a UHV station 1002 and a laser system 1004 with mirrors external to the UHV station 1002.

[0054] As shown in Figure 11, a quantum particle cell fabrication system 1100 includes a UHV station 1102 and a laser system 1104 to fabricate cells (such as cell 1106). As shown in the detailed view, a pulsed laser system 1104 is used to etch patterns into the exterior-facing surface 1100 and the vacuum-facing surface 1112. The heat from the laser beam is capable of transforming material in a 100 μm deep region while leaving nearby areas unaffected. As shown in Figure 12, the system 1100 may be utilized with an insert 1202 that may be utilized to direct flowing steam used to remove ablation residue.

[0055] Figure 13 shows a pair of completed quantum particle cells 1302 and 1304. Figure 14 shows a quantum particle cell 1402 fitted with a stainless steel port 1404 that may be utilized for maintenance cycles to re-establish a vacuum, for example after a bake-out procedure.

[0056] As used herein, a "quantum particle" is a molecular entity that includes at least the nucleus of an alkali metal atom or an alkaline earth metal atom. A "molecular entity" is any structurally or isotopically distinct atom, molecule, ion, ion pair, radical, radical ion, complex, conformer, etc., that can be identified as an individually distinguishable entity. As used herein, an "atom" includes neutral atoms and single atomic ions. A quantum particle species includes all quantum particles that have the same positive number of protons and the same positive number of neutrons. For example, molecular entities including rubidium-87, other isotopes of rubidium, other alkali metals, strontium and other alkaline earth metals, and yttrium and other rare earth metals are quantum particle species.

[0057] A "quantum particle cell" is a vacuum cell containing a quantum particle, which is intended to be utilized such that the quantum particle can be in a first quantum state, a second quantum state, and a superposition of these quantum states. A quantum particle cell includes one or more vacuum boundary walls that separate the internal vacuum from the atmosphere. A vacuum boundary wall typically includes a vacuum-facing surface, some of which actually faces the vacuum, and some of which do not (e.g., because it is bonded to another wall).

[0058] Lasers of interest herein are capable of generating laser pulses of durations of 1 femtosecond, 10 femtoseconds, 1 picoseconds, 10 picoseconds, and less than 1 nanosecond. Electromagnetic radiation (EMR) wavelengths are provided, including ultraviolet, visible, and infrared wavelengths.

[0059] In this specification, any technology indicated as "prior art" is recognized as prior art, and any technology not indicated as "prior art" is not recognized as prior art. The above-mentioned embodiments, modifications, and variations thereof are provided by the present invention, and the scope of the present invention is defined by the following claims. [Application Example 1] A modification process for a quantum particle cell, comprising: Assembling a vacuum cell structure having a first vacuum boundary wall, the vacuum cell structure comprising: -9 defining an interior having a pressure of less than Torr, the vacuum cell structure including a plurality of quantum particles having an equal positive number of protons and an equal positive number of neutrons; directing a laser pulse of less than 1 nanosecond duration from outside the vacuum cell through the first vacuum boundary wall to modify a vacuum-facing surface of the vacuum cell when the vacuum cell contains the plurality of quantum particles; A process comprising: [Application Example 2] The manufacturing process for the quantum particle cell according to Application Example 1, wherein the quantum particles include alkali metal atoms, alkaline earth metal atoms, or rare earth metal atoms. [Application Example 3] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse forms or strengthens a bond between the first vacuum boundary wall and the second vacuum boundary wall. [Application Example 4] A manufacturing process for a quantum particle cell as described in Application Example 3, wherein the assembling includes contact-bonding or anodic-bonding the first vacuum boundary wall to the second vacuum boundary wall without utilizing a laser pulse. [Application Example 5] The manufacturing process for a quantum particle cell according to Application Example 4, wherein the contact bonding or anodic bonding is performed only at a temperature below 200°C. [Application Example 6] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse chemically modifies a portion of the vacuum-facing surface of the vacuum cell. [Application Example 7] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse changes the electrical conductivity of a portion of the vacuum-facing surface of the vacuum cell. [Application Example 8] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse removes material from the vacuum-facing surface of the vacuum cell. [Application Example 9] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse has a duration of less than 10 picoseconds. [Application Example 10] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the laser pulse has a duration of less than 10 femtoseconds. [Application Example 11] A manufacturing process for a quantum particle cell according to Application Example 1, wherein the volume of the vacuum within the quantum particle cell is less than 1 milliliter. [Application Example 12] An ultra-high vacuum (UHV) quantum particle cell, 1. A quantum particle cell structure comprising a first vacuum boundary wall, a second vacuum boundary wall, and a pulsed laser junction physically connecting the first and second vacuum boundary walls, comprising: -9 A quantum particle cell structure that isolates the sub-Torr internal pressure from the atmosphere; a quantum particle having an equal positive number of protons and an equal positive number of neutrons, the quantum particle being contained within said quantum particle structure; A UHV quantum particle cell comprising: [Application Example 13] A UHV quantum particle cell according to Application Example 12, further comprising third, fourth and fifth vacuum boundary walls, and the pulsed laser bonding physically connects the first vacuum boundary wall to the second, third, fourth and fifth vacuum boundary walls. [Application Example 14] A UHV quantum particle cell according to Application Example 13, wherein the second and fourth vacuum boundary walls are contact-bonded to the third and fifth vacuum boundary walls, respectively. [Application Example 15] A UHV quantum particle cell according to Application Example 12, further comprising a contact bond or an anodic bond between the first and second vacuum boundary walls. [Application Example 16] A UHV quantum particle cell according to Application Example 12, wherein the volume of the vacuum within the quantum particle cell is less than 1 milliliter.

Claims

1. 1. A process for manufacturing a quantum particle cell, comprising: Assembling a vacuum cell structure having a first vacuum boundary wall, the vacuum cell structure comprising: －９ defining an interior having a pressure of less than 1000 MPa (1000 MPa) and the vacuum cell structure including a plurality of quantum particles having an equal positive number of protons and an equal positive number of neutrons; directing a laser pulse of less than 1 nanosecond duration from outside the vacuum cell structure through the first vacuum boundary wall to modify a vacuum-facing surface of the vacuum cell structure when the vacuum cell structure contains the plurality of quantum particles; A process comprising:

2. 10. The process for manufacturing a quantum particle cell of claim 1, wherein the quantum particles comprise alkali, alkaline earth, or rare earth metal atoms.

3. 10. The quantum particle cell manufacturing process of claim 1, wherein the laser pulse creates or strengthens a bond between the first and second vacuum boundary walls.

4. 4. The quantum particle cell manufacturing process of claim 3, wherein the assembling comprises contact or anodic bonding the first vacuum boundary wall to the second vacuum boundary wall without utilizing a laser pulse.

5. 5. The quantum particle cell manufacturing process of claim 4, wherein the contact or anodic bonding is performed only at temperatures below 200 degrees Celsius.

6. 10. The quantum particle cell manufacturing process of claim 1, wherein the laser pulse chemically modifies a portion of the vacuum-facing surface of the vacuum cell structure.

7. 10. The quantum particle cell fabrication process of claim 1, wherein the laser pulse alters the electrical conductivity of a portion of the vacuum-facing surface of the vacuum cell structure.

8. 10. The quantum particle cell fabrication process of claim 1, wherein the laser pulse removes material from the vacuum-facing surface of the vacuum cell structure.

9. 10. The quantum particle cell manufacturing process of claim 1 , wherein the laser pulse has a duration of less than 10 picoseconds.

10. 10. The quantum particle cell manufacturing process of claim 1 , wherein the laser pulse has a duration of less than 10 femtoseconds.

11. 10. The quantum particle cell manufacturing process of claim 1, wherein a volume of vacuum within the quantum particle cell is less than 1 milliliter.

12. 1. An ultra-high vacuum (UHV) quantum particle cell comprising:

1. A quantum particle cell structure comprising a first vacuum boundary wall, a second vacuum boundary wall, and a pulsed laser junction physically connecting the first and second vacuum boundary walls, －９ a quantum particle cell structure that isolates the sub-Torr internal pressure from the atmosphere; a quantum particle having an equal positive number of protons and an equal positive number of neutrons, the quantum particle being contained within the quantum particle cell structure; A UHV quantum particle cell comprising:

13. 13. The UHV quantum particle cell of claim 12, further comprising third, fourth and fifth vacuum boundary walls, the pulsed laser bonding physically connecting the first vacuum boundary wall to the second, third, fourth and fifth vacuum boundary walls.

14. 14. The UHV quantum particle cell of claim 13, wherein the second and fourth vacuum boundary walls are contact-bonded to the third and fifth vacuum boundary walls, respectively.

15. 13. The UHV quantum particle cell of claim 12, further comprising a contact or anodic bond between the first and second vacuum boundary walls.

16. 13. The UHV quantum particle cell of claim 12, wherein a volume of vacuum within the quantum particle cell is less than 1 milliliter.

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