Microwave resonator device including at least one dielectric resonator member configured to provide for resonant field enhancement

A microwave resonator device including a first resonator member comprised of a dielectric material and a second resonator member comprised of a dielectric material. The second resonator member can be positioned spatially offset from the first resonator member to define a spatial interaction region configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum. The spatial offset between the first resonator member and the second resonator member defining the spatial interaction region is less than the microwave wavelength associated with a resonant frequency of the microwave resonator device. The microwave resonator device facilitates generation of a resonant field enhancement within the spatial interaction region.

BACKGROUND

Microwave resonators are often utilized in applications involving field sensing, time keeping, oscillators, and many others. Current microwave resonators are of a sufficiently large size that they are not useful for many applications in which field sensing, time keeping, and other applications are desired to be utilized. For example, some current resonators have a large mode volume of 10 cc-100 cc and larger. Additionally, some current resonators suffer from losses that limit the quality and efficiency of the resonators. As such, there is a desire in the industry to fabricate smaller, more compact microwave resonators with higher quality factors to increase the possible uses as well as reliability and efficiency for microwave resonators.

DETAILED DESCRIPTION OF THE INVENTION

In describing and claiming the present disclosure, the following terminology will be used in accordance with the definitions set forth below.

The singular forms “a,” “an,” and, “the” include express support for plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a pin” includes reference to one or more of such pins, and reference to “the arm” includes reference to one or more of such arms.

The term “coupled,” as used herein, is defined as directly or indirectly connected in a chemical, mechanical, electrical, fluidic, non-mechanical, non-chemical, nonelectrical, or non-fluidic manner. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. “Directly coupled” objects, structures, elements, or features are in contact with one another and may be attached. Further as used in this written description, it is to be understood that when using the term “coupled” support is also afforded for “directly coupled” and vice versa.

As used herein, comparative terms such as “increased,” “decreased,” “better,” “worse,” “higher,” “lower,” “enhanced,” “maximized,” “minimized,” and the like refer to a property of a device, system, step, component, composition, or activity that is measurably different from other devices, components, compositions or activities that are in a surrounding or adjacent area, that are similarly situated, that are in a single device or composition or in multiple comparable devices or compositions, that are in a group or class, that are in multiple groups or classes, or as compared to the known state of the art.

As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. Unless otherwise stated, use of the term “about” in accordance with a specific number or numerical range should also be understood to provide support for such numerical terms or range without the term “about”. For example, for the sake of convenience and brevity, a numerical range of “about 50 angstroms to about 80 angstroms” should also be understood to provide support for the range of “50 angstroms to 80 angstroms.” Furthermore, it is to be understood that in this specification support for actual numerical values is provided even when the term “about” is used therewith. For example, the recitation of “about” 30 should be construed as not only providing support for values a little above and a little below 30, but also for the actual numerical value of 30 as well.

Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of devices, methods, systems, elements thereof, etc., to provide a thorough understanding of various exemplary embodiments. One skilled in the relevant art will recognize, however, that such detailed embodiments do not limit the overall inventive concepts articulated herein, but are merely representative thereof.

An initial overview of the inventive concepts is provided below and then specific examples are described in further detail later. This initial summary is intended to aid readers in understanding the examples more quickly, but is not intended to identify key features or essential features of the examples, nor is it intended to limit the scope of the claimed subject matter.

Described herein is a microwave resonator device. The microwave resonator device can include a first resonator member comprised of a dielectric material. The microwave resonator can further include a second resonator member comprised of a dielectric material, the second resonator member being positioned spatially offset from the first resonator member to define a spatial interaction region between the first resonator member and the second resonator member configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum. The spatial offset between the first resonator member and the second resonator member defining the spatial interaction region is less than a microwave wavelength associated with a resonant frequency of the microwave resonator device. The microwave resonator device facilitates generation of a resonant field enhancement within the spatial interaction region.

Described herein is a microwave resonator device. The microwave resonator device can include a resonator member comprised of a dielectric material and configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum. The thickness of the resonator member can be smaller than a microwave wavelength associated with a resonant frequency of the microwave resonator device. The microwave resonator device can facilitate generation of a resonant field enhancement within around in proximity to the resonator member.

Described herein is a method of facilitating formation of a microwave resonator device. The method can comprise configuring a first resonator member to be comprised of a dielectric material. The method can further comprise configuring a second resonator member comprised of a dielectric material to be spatially offset from the first resonator member to define a spatial interaction region between the first resonator member and the second resonator member configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum. A thickness of the first resonator member and a thickness of the second resonator member are smaller than a microwave wavelength associated with a resonant frequency of the microwave resonator device. The spatial offset between the first resonator member and the second resonator member defining the spatial interaction region can be less than the microwave wavelength associated with the resonant frequency. The microwave resonator device can facilitate generation of a resonant field enhancement within the spatial interaction region.

Disclosed herein is a method of facilitating formation of a microwave resonator device. The method can comprise configuring a resonator member that is configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum to comprise a thickness measured in a direction parallel to a longitudinal axis of the resonator member. The method can further comprise configuring the resonator member to be composed of a dielectric material. The method can further include configuring the thickness of the resonator member to be smaller than a microwave wavelength associated with a resonant frequency of the microwave resonator device.

To further describe the present technology, examples are now provided with reference to the figures. With reference toFIG.1A, a microwave resonator100in accordance with an example of the present disclosure is illustrated. The microwave resonator100shown can be a resonator configured to confine waves (e.g., an electromagnetic field) in the microwave range of the electromagnetic spectrum. The microwave resonator100can be a dual member resonator including a first resonator member102and a second resonator member104. The first and second resonator members102and104, as illustrated, can be disk shaped. However, the shape of the resonator members is not intended to be limited in any way by this disclosure. The resonator members can have a disk shape, a ring shape, or any other shape. For example, shapes with corners can also be used to get enhanced edge effects for in/out coupling or sensing. In short, any workable shape for a microwave resonator can be used.

The first resonator member102and the second resonator member104can be positioned parallel to each other. The first resonator member102and the second resonator member104can further be axially aligned with each other such that centers and axes of each of the first resonator member102and the second resonator member104are in substantial alignment with each other. The first resonator member102and the second resonator member104can be positioned apart from each other to be spatially offset from each other. The spatial offset between the first resonator member102and the second resonator member104can define a spatial interaction region106between the first resonator member102and the second resonator member104.

The spatial interaction region106can be configured to confine an electromagnetic field provided to the microwave resonator by a microwave emitter or by an outside environment. The electromagnetic field can be a field in a microwave region of the electromagnetic spectrum. The electromagnetic field confined in the spatial interaction region106of the microwave resonator100can comprise microwaves having a wavelength and frequency substantially the same as a resonant frequency/wavelength of the microwave resonator100, to which the microwave resonator100is tuned.

The spatial interaction region can be configured to contain a vacuum between the first resonator member and the second resonator member, a gas material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member, a solid material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member, or a liquid material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member.

As further illustrated inFIG.1A, a first mount108can be coupled to the first resonator member102. A second mount110can be couple to the second resonator member104. The mounts108and110can be made of a same or different materials then the first resonator member102and the second resonator member104. The mounts108and110can be mounted to the resonator members102and104using any known method for coupling a mount to a resonator member, such as adhesive, welding, mechanical coupling, or any other known method that does not adversely affect the function of the resonator to an undesirable amount. The method of mounting the mounts to the resonator members is not intended to be limited by this disclosure in any way.

The first mount108and the second mount110can facilitate mounting the microwave resonator100to an enclosure. Specifically, the first mount108can facilitate mounting the first resonator member102to an inner surface of an enclosure and the second mount can facilitate mounting the second resonator member104to an inner surface of an enclosure. The mounts108and110can be sized to ensure that the resonator members are disposed apart at the spatial offset to define the spatial interaction region106.

As shown inFIG.1B, the first resonator member102can be a disk having a size at least partially defined by a radius R1. Similarly, the second resonator member104can be a disk having a size at least partially defined by a radius R2. As shown inFIG.10, the first resonator member102can be a disk having a thickness T1. The second resonator member104can be a disk having a thickness T2.

The first resonator member102and the second resonator member104can be spaced apart by a spatial offset D1, which is a distance between the first resonator member102and the second resonator member104as shown inFIG.10. The spatial interaction region106disposed between the first resonator member102and the second resonator member104can be defined by one or more of the spatial offset D1and the radii R1and R2of the first resonator member102and the second resonator member104. For example, the spatial interaction region106can be an area bounded between the resonator members102and104and can have a size corresponding to the size of the spatial offset D1. The spatial interaction region106can further be defined by the surface sizes of the first resonator member102and the second resonator member104.

For example, the spatial interaction region106, as illustrated inFIGS.1A-1C, can be a substantially cylindrical volume between the disk-shaped resonator members102and104. The volume of the spatial interaction region106can be calculated by determining a volume of a cylinder having a radius (e.g., R1and R2) and a height (e.g., D1). The volume V of the spatial interaction region106can be expressed as:
V=πr2h
where “r” is the radius (e.g., R1, R2) of the spatial interaction region106and h is the height (e.g., D1) of the spatial interaction region106.

With reference toFIG.2A, a microwave resonator200in accordance with an example of the present disclosure is illustrated. The microwave resonator200shown can be a resonator configured to confine waves (e.g., an electromagnetic field) in the microwave range of the electromagnetic spectrum. The microwave resonator200can be a single member resonator including a resonator member202. The resonator members202, as illustrated, can be disk shaped. However, the shape of the resonator member is not intended to be limited in any way by this disclosure. The resonator members can have a disk shape, a ring shape, or any other shape.

In the case of microwave resonator200, in which no region is defined between multiple resonator members, the spatial interaction region can be the resonator member202itself. The resonator member202can be configured to confine an electromagnetic field in and around the resonator member202that is provided to the microwave resonator200by a microwave emitter or by an outside environment. The electromagnetic field can be a field in a microwave region of the electromagnetic spectrum. The electromagnetic field confined in and around the resonator member202of the microwave resonator200can comprise microwaves having a wavelength and frequency substantially the same as a resonant frequency/wavelength of the microwave resonator200, to which the resonator is tuned.

As further illustrated inFIG.2A, a mount208can be coupled to the resonator member202. The mount208can be made of a same or different materials then the resonator member202. The mount208can be mounted to the resonator member202using any known method for coupling a mount to a resonator member, such as adhesive, welding, mechanical coupling, or any other known method that does not adversely affect the function of the resonator to an undesirable amount. The method of mounting the mount to the resonator member202is not intended to be limited by this disclosure in any way.

The mount208can facilitate mounting the microwave resonator200to an enclosure. Specifically, the mount208can facilitate mounting the resonator member202to an inner surface of an enclosure. The mount208can be sized to ensure that the resonator member202is disposed at a desired position within the enclosure. As shown inFIG.2B, the resonator member202can be a disk having a size at least partially defined by a radius R3. As shown inFIG.2C, the resonator member202can be a disk having a thickness T3.

A region in and around the resonator member202can define a spatial interaction region configured to confine the electromagnetic field in the microwave range of the electromagnetic spectrum. The spatial offset region can be defined at least partially by the resonator member202of the microwave resonator202. Accordingly, the spatial offset region can be at least partially a substantially cylindrical volume defined by the resonator member202. The volume of resonator member202can be calculated by determining a volume of a cylinder having a radius R3and a height T3. For example, the volume V of the spatial offset region can be expressed as:
V=πr2h
where “r” is the radius (e.g., R3) of the resonator member202and h is the height (e.g., T3) of the resonator member202.

As shown inFIG.3, the microwave resonator100can be contained in an enclosure302to form a microwave resonator system300. The enclosure302can include an outer wall304, an upper wall306, and a lower wall308that together define an inner cavity310configured to receive the microwave resonator100. The mount108coupled to the first resonator member102can be coupled to the upper wall306. The mount110coupled to the second resonator member104can be coupled to the lower wall308. The first resonator member102and the second resonator member104can be mounted respectively to the upper wall306and the lower wall308of the enclosure302with mounts108and110appropriately sized to dispose the resonator members within the inner cavity310to maintain the size of the spatial interaction region106between the first and second resonator members.

The enclosure can be configured to contain a vacuum between the first resonator member and the second resonator member, a gas material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member, a solid material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member, or a liquid material of lower dielectric constant than a dielectric constant in the first resonator member and the second resonator member.

As shown inFIG.4, the microwave resonator200can be contained in an enclosure402to form a microwave resonator system400. The enclosure402can include an outer wall404as well as an upper wall406and a lower wall408joined by the outer wall404. The walls404,406, and408can together define an inner cavity410configured to receive the microwave resonator200. The mount208coupled to the resonator member202can be coupled to the upper wall406or the lower wall408. The resonator member202can be mounted to the upper wall406or the lower wall408of the enclosure402with mount208appropriately sized to dispose the resonator member202within the inner cavity410.

The enclosure can be configured to contain a vacuum, a gas material of lower dielectric constant than a dielectric constant in the resonator member, a solid material of lower dielectric constant than a dielectric constant in the resonator member, or a liquid material of lower dielectric constant than a dielectric constant in the resonator member.

The enclosures302and402can shield the microwave resonators100and200from outside microwaves, electromagnetic radiation, disturbances, perturbations, and/or environmental conditions and factors that may disturb the devices in order to ensure proper functioning of the microwave resonators100and200. The enclosures can be made of a metal such as aluminum or copper, or a non-metal, or any material known for holding a microwave resonator. The material of the enclosure is not intended to be limited by this disclosure in any way. Additionally, the shape of the enclosure is not intended to be limited in any way. The enclosure may be cylindrical as shown or can be spherical, square, pyramidal, conical, or of any other shape having any number of sides and defining an inner cavity for storing a microwave resonator.

FIGS.5A,5B, and5Cillustrate intensity profiles of microwave propagation within dual disk microwave resonators such as the microwave resonator100.FIG.5Aillustrates possible configurations of a microwave resonator. For example, the microwave resonator can be the microwave resonator100ofFIG.1Ain which the resonator members are each disk shaped. Furthermore, the microwave resonator can have an alternative configuration where the resonator members are ring-shaped members, such as microwave resonator100A. The shape of the microwave resonators and/or associated spatial interaction region are not intended to be particularly limited by this disclosure; any shape that is workable for confining microwaves of electromagnetic radiation can be used for the resonator members or spatial interaction region. In the illustrated configurations, the microwave resonators100and100A can be configured as whispering gallery mode resonators that propagate whispering gallery waves or modes. Whispering gallery waves/modes are a type of wave that can travel around near an outside perimeter of a circular member or a concave surface.

FIG.5Billustrates a cross-sectional view of the microwave resonator100zoomed in at about region B illustrated inFIG.5A. Although microwave resonator100is illustrated, it will be appreciated that the field intensity profile of microwaves would be similar in the microwave resonator100A. InFIG.5B, a microwave field intensity profile is illustrated in a wave region WR located at an outer region of the microwave resonator100. In the spatial interaction region, the intensity profile can have a high area H in which the intensity of the electromagnetic microwave field is at a peak intensity. Outside the high H, the intensity of the microwave field can decrease to a medium region M and a low region L. Although the regions of microwave intensity in the wave region WR are illustrated as discrete areas, it will be appreciated that the intensity of the microwave field can gradually vary throughout the wave region WR. The intensities of the microwave field will likely not be at discrete levels in discrete blocks but will instead vary in intensity as a spectrum throughout the spatial interaction region106at a theoretically infinite number of intensities.

FIG.5Cshows a top view illustration of intensities of waves propagating in the spatial interaction region106. As illustrated the can be confined in the spatial interaction region106to propagate around an outer region of the spatial interaction region106substantially near a circumference of the spatial interaction region106.FIG.5BandFIG.5Cillustrate intensities of an electromagnetic field with a vertical polarization in the spatial interaction region106. In other words, the electromagnetic field in the spatial interaction region is oriented predominantly in a plane arranged in a same direction as the thickness of the resonator members defining the spatial interaction region106. Polarization of an electromagnetic field in microwave resonators can also be in transverse polarization in which the electromagnetic field is oriented predominantly in a plane of the disk, which is normal to the thickness of the disk.

FIGS.6A and6Billustrate intensity profiles of microwave propagation within a single disk microwave resonators such as the microwave resonator200.FIG.6Aillustrates possible configurations of a microwave resonator. For example, the microwave resonator can be the microwave resonator200ofFIG.2Ain which the resonator members are each disk shaped. Furthermore, the microwave resonator can have an alternative configuration where the resonator members (e.g., see resonator member202A) are ring-shaped members, such as microwave resonator200A. The shape of the microwave resonators is not intended to be particularly limited by this disclosure; any shape that is workable for confining microwaves of electromagnetic radiation can be used for the resonator members. In the illustrated configurations, the microwave resonators200and200A can be configured as whispering gallery mode resonators that propagate whispering gallery waves or modes.

FIG.6Billustrates a cross-sectional view of the microwave resonator200zoomed in at about region C illustrated inFIG.6A. Although microwave resonator200is illustrated, it will be appreciated that the field intensity profile of microwaves would be similar in the microwave resonator200A. InFIG.6B, a microwave field intensity profile is illustrated in a wave region WR1located at an outer region of the microwave resonator200. In the spatial interaction region (e.g., the resonator member and area around the resonator member), the intensity profile can have a high area H1in which the intensity of the electromagnetic microwave field is at a peak intensity. Outside the high H1, the intensity of the microwave field can decrease to a medium region M1and a low region L1.

FIG.6Billustrates a case where polarization of an electromagnetic field in the microwave resonator can be in transverse polarization in which the electromagnetic field is oriented predominantly in a plane of the disk, which is normal to the thickness of the disk. In this case, an additional wave region WR2can be found at a circumferential edge of the resonator member. In the spatial interaction region (e.g., the resonator member and area around the resonator member) including wave region WR2, the intensity profile can have a high area H2in which the intensity of the electromagnetic microwave field is at a peak intensity. Outside the high H2, the intensity of the microwave field can decrease to a medium region M2and a low region L2.

Although the regions of microwave intensity in the wave regions WR1and WR2are illustrated as discrete areas, it will be appreciated that the intensity of the microwave field can gradually vary throughout the wave regions WR1and WR2. The intensities of the microwave field will likely not be at discrete levels in discrete blocks but will instead vary in intensity as a spectrum throughout the spatial interaction region and/or around the resonator member202at a theoretically infinite number of intensities.

Similar to as illustrated inFIG.5C, the microwaves can be confined to propagate around an outer region of the resonator member202substantially near a circumference of the resonator member202.FIG.6Billustrate intensities of an electromagnetic field with a transverse polarization in and around the resonator member202. In other words, the electromagnetic field in the spatial interaction region is oriented predominantly in a plane resonator member202. Polarization of an electromagnetic field in microwave resonators can also be in vertical polarization in which the electromagnetic field is oriented predominantly in a plane normal to a longitudinal surface of the resonator member202.

Structures and wave propagation in exemplary microwave resonators have been described above and illustrated in the figures. With respect to the microwave resonators described herein, certain features and elements of the microwave resonators act to facilitate generation of a resonant field enhancement within the spatial interaction region and/or the resonator members. Resonant field enhancement as described herein, and as facilitated by the design of the microwave resonators, means that field intensities of electromagnetic radiation and microwaves in the resonators can be several orders of magnitude higher than would be expected in devices of similar size and power consumption. The resonant field enhancement in the microwave resonators described herein can allow measurement precision that is substantially higher than would be expected without the resonant enhancement of the microwave field.

Various elements of the microwave resonators can be varied, changed or modified in order to obtain a desirable resonance enhancement factor for the microwave resonator. The resonance enhancement factor or “REF” can be defined as a characteristic of a microwave resonator that results in a multiplier of a microwave field intensity over that of a microwave field intensity of a microwave field in the absence of the microwave resonator. For example, in a case of a microwave field in the absence of a microwave resonator, in which the microwave field intensity (of an arbitrary unit (a.u.)) of the microwave field of a certain frequency is 5, the same microwave field associated with a microwave resonator as taught herein having a microwave field intensity of 10 would result in a REF of the microwave resonator being 2. The microwave resonators described herein have dimensions, spacings, and materials for resonator members that achieve a REF of substantially around 103or greater. Accordingly, the microwave resonator according to the principles described herein are compact dielectric whispering gallery mode (WGM) microwave resonators with inherent high resonance enhancement factor of 103or greater and with small microwave effective mode volume which is a volume (e.g. spatial interaction region106or resonator members) where the microwave mode energy is constrained within the resonator.

The resonator members of the microwave resonators described herein can be made of a dielectric material. The dielectric material can have a high dielectric constant (e.g. greater than 20, greater than 60) and low microwave loss tangent (e.g. <10−4, <10−3, <10−2), although the range of the dielectric constant and microwave loss tangent are not intended to be particularly limited by this disclosure in any way. Exemplary dielectric materials for the resonator members can include Rutile (TiO2) and/or Strontium Titanate (SrTiO3), Lithium Niobate, Lithium Tantalate, Sapphire, Diamond, Silicon, Silicon Carbide (SiC), Yttrium Aluminum Garnet (YAG), KTaO3, or any dielectric material with dielectric constant sufficient to produce a desired resonance enhancement factor in the microwave resonator. In general, any dielectric materials can be used in the resonators, particularly dielectric materials with environmental stability, relatively low microwave loss, and/or relatively high dielectric constants. High dielectric constants in dielectric materials used in the resonator members lead to small devices and manufacturing repeatability.

Furthermore, isomorphic versions of dielectric materials can be used as well doped variants of the dielectric materials. For example, Sapphire is a commonly used dielectric material. Additionally, sapphire can be doped with another material in order to alter certain physical parameters and characteristics of the sapphire. For example, Yttrium Aluminum Garnet (commonly referred to as YAG), is essentially Sapphire with the Yttrium atom replacing some of the Aluminum atoms in the sapphire. This allows the dielectric material to be co-doped with other trace elements to tune electrical and optical properties.

Optical absorption or conductivity of sapphire, for example, can be altered by doping and can then be exploited to tune the microwave resonator to a desired resonant frequency. Isomorphic dielectric materials and doped variants can be used to obtain different resonance enhancement factors for the microwave resonators described herein.

Dielectric materials that have a dielectric constant larger than ˜40 for microwave frequencies around 10 GHz are desirable for use in the resonator members of the microwave resonators described herein. When the microwave frequency goes higher to 100 GHz the dielectric constant can be a smaller number such as 20-30 and up to any higher number.

In microwave resonator100ofFIGS.1A-1C, for example, two high-dielectric constant resonator members102and104in the form of disks with spatial interaction region106between them facilitates a large resonant field enhancement occurs in the spatial interaction region106due to the presence of the two resonator members (disks). The gap D1between the two resonator members102and104can be adjusted to certain distances to achieve a high REF of 103or greater (or even 102or greater). For example, with reference toFIGS.1A-1C, andFIGS.7A and7BFIG.7Aillustrates a graph showing the effect of setting a vertical distance in mm between resonator members102and104to achieve a high field intensity in arbitrary units (a.u), and therefore, a high REF. As shown, a large spike in microwave field intensity results in a range of vertical distances between the resonator members. Distances that are too large or too small can cause a large drop off in field intensity. Accordingly, the distance between resonator members can be adjusted to improve field intensity and obtain a needed or desired REF factor of a microwave resonator.

Additionally, radius size of R1and R2of the resonator members can be modified to achieve a high field intensity and to modify the REF of the microwave resonator. With reference toFIGS.1A-1CandFIG.7B, the field intensity in the microwave resonator can increase significantly based on radius size or radial distance in mm of the resonator members102and104. Accordingly, the REF can be optimized or increased based on radial size of the resonator members102and104of the microwave resonator. It will be appreciated that the radius of the resonator members and the distance between the resonator members define a volume of the spatial interaction region where the microwaves are confined. In other words, the volume of the spatial interaction region can affect the REF of a microwave resonator.

The geometrical dimension of the resonators and resonator members described herein can be within 0.1 CC to 0.5 CC volume. The microwave mode volume (e.g., the volume of the spatial interaction region106or resonator member202where microwave fields are confined) can be (for example) as small as 0.001λ13, where λ1 is the microwave wavelength associated with the resonant frequency or resonant frequencies of the microwave resonator.

With the architecture described in the dual disk configuration, the thickness of the spatial interaction region106can be very compact compared to current microwave resonators. The thickness D1of the spatial interaction region106can be 100 times smaller than the wavelength λ1, or even smaller. The dual disk architecture enables a strong intensity localization in the spatial interaction region near the perimeter of the resonator members102and104. The large refractive index of the dielectrics used for the resonator members102and104can cause the resonator members102and104to act as two hard walls to confine the microwave mode for the vertical polarization between the two resonator members102and104.

As shown inFIGS.7A and7B, well-contained high intensity microwave fields in the spatial interaction region106can create microwave field intensities in the microwave resonator100that can be several orders of magnitude higher than would be expected in devices of similar size, dimension, and power consumption. The larger than expected field intensities are a result of the high resonance enhancement factor found in the devices as described herein that cause a regular microwave field to be intensified by a multiple of 103. The intensified microwave field in the resonator can allow for measurement precision that is substantially higher than would be expected without the resonance enhancement of the microwave field by the microwave resonator described herein. Additionally, presence of appropriate microwave components in close proximity to the disk assembly allows tuning of the assembly's resonance frequency.

In microwave resonator200ofFIGS.2A-2C, a high-dielectric constant single disk is used as the resonator member202. The resonator member202can have a thickness T3that is smaller than λ2, which is the microwave wavelength associated with the resonant frequency or resonant frequencies of the microwave resonator200. In microwave resonator200, the microwave energy can be delocalized into the air as well as being contained within the resonator member202. The thickness T3can be 100 times smaller or smaller than the wavelength λ2 of the resonant frequency of the resonator. In the structure of the microwave resonator200shown inFIG.2A, the resonator can be a WGM resonator where a substantial portion of the microwave energy is in the air. The small thickness T3of the disk helps delocalize the mode energy from the dielectric material to the air. With reference toFIGS.2A-2CandFIG.6B, the mode maximum, or maximum field intensity, is close to the perimeter of the disk and a substantial amount of energy is contained in the environment surrounding the resonator member202. The presence of the field in the air allows the field to interact with microwave active components external to the resonator member202and placed in moderate to high intensity microwave field locations. Additionally, presence of appropriate microwave components in close proximity to the disk allows tuning of the assembly's resonance frequency. The geometrical dimension of these resonators can be within 0.1-0.5 CC volume, and the microwave mode volume (e.g. resonator member202) can be (for example) as small as 0.001λ23, where λ2 is the microwave wavelength of the resonator.

For both the microwave resonator100and the microwave resonator200, the high resonance enhancement factors and the small volumes can give the microwave resonators very high quality factors and very high quality Q to volume V ratios. The high Q/V ratio is a figure of merit for many applications where microwave resonators are used such as Magnetometry and Electrometry and other sensing and measurement applications.

In both the microwave resonator100and the microwave resonator200, most or all of the microwave mode energy can be confined to the air or environment adjacent to the resonator members102,104, or202rather than in the dielectric host material of the resonator members102,104, or202. With most of the field energy confined to the air or surrounding environment, interaction of the microwave energy with any external components placed at the proximity of the resonators100and200can be strong. For the two disc configuration (e.g. resonator100), this allows placement of RF interacting materials and components, such as photonic resonators, photonic frequency converters, quantum-capable materials (such as vacancy-doped diamond and silicon-carbide), and/or other microwave-active technology in the high-field intensity air-gap region (e.g. spatial interaction region106) to enhance the microwave-material and component interactions. In the one-disc configuration (e.g. resonator200), this allows placement of microwave active components in close proximity to the disk (e.g., resonator member202) to enable enhanced interactions between the microwave field confined by the resonator and RF interacting materials and components such as photonic resonators, photonic frequency converters, quantum-capable materials (such as vacancy-doped diamond and silicon-carbide), and/or other microwave-active technology.

With the resonator configurations discussed herein, RF and microwave field sensing can be accomplished using either of microwave resonators100or200in conjunction with one or more electro, magnetic, or microwave sensitive components. For example,FIG.8illustrates a configuration of microwave resonator100and components used therein to measure the intensity of a microwave field within the spatial interaction region106. As shown a microwave sensitive component800can be inserted into spatial interaction region106to sense/measure characteristics of a microwave field in the spatial interaction region106. The microwave sensitive component800can be a photonic coupled resonator that supports two resonances based on elements802and804. Each of elements802and804can have a resonance, respectively represented as resonance ω1and resonance ω2. The spacing between the resonances ω1and ω2can be equal to an RF frequency. The microwave sensitive component800can be inserted into the spatial interaction region106of the microwave resonator100as shown inFIG.8.

RF field sensing using the microwave sensitive component800can occur as follows with reference toFIG.8. An RF signal F with a given amplitude and frequency, which matches the resonant frequency of the microwave resonator100, reaches the spatial interaction region106of the microwave resonator100. It will be understood that the resonant frequency of the resonator can be altered or tuned to a certain frequency by inserting a dielectric element or dielectric body within the spatial interaction region106in a controlled manner to be disposed in a specific position associated with a desired resonant frequency of the resonator.

Due to the nature, architecture, and construction of the microwave resonator100, the intensity of the RF signal F is enhanced at the resonant frequency of the resonator. The microwave sensitive component800can sense and provide a signal containing characteristics of the RF signal F and additional microwave fields within the spatial interaction region106. The signal can be sent to a computer containing a processor and/or program that reads out the signal and creates data representing the characteristics of the signal from the microwave sensitive component800to sense and measure fields in the resonator100.

Additionally, information associated with the RF signal F can be brought into the optical domain for sensing and measuring. For example, in a case the microwave sensitive component800can be an electro-optic coupled photonic resonator inserted into the spatial interaction region106to do RF field sensing. The microwave sensitive component800can be connected to a cable806and808, being an optical fiber. The intensity of the RF signal F can match a frequency of the microwave resonator100and can be enhanced by the microwave resonator100. The RF signal F intensity can interact with the microwave sensitive component800and mix with the optical signal of the microwave sensitive component800. For mixing the RF signal F with an optical signal, a laser light L with an amplitude A and frequency ω1matching one of the resonant frequencies of the microwave sensitive component800. The laser light L enters the photonic resonator (e.g. which is a type of the microwave sensitive component800) at location806and is enhanced due to the optical resonance between the frequency ω1of the laser light L and the frequency ω1of the photonic resonator. The laser light L interacts with the RF signal and is mixed due to the nonlinear mixing property of the photonic material which is called an electro-optic property. The mixing of the laser light with the microwave field will generate a frequency ω2=ω1+Ω (where Ω is the frequency of the RF signal F). Additionally, ω2is also the second resonance is an RF resonance of the coupled photonic resonator. This second resonance enhances the generated signal at the frequency of ω2. In this mixing approach, ω2is a sideband to ω1with the information of the RF signal F (Ω).

The amplitude of the information at the frequency ω2is proportional to κ×L×F, where κ coefficient has the enhancement factor due to the optical resonance and the RF resonance, as well as the nonlinear mixing factor which is also called the electro-optic coefficient. Using the differences between the frequencies of the laser light L and the RF signal F and the resonant frequencies ω1, ω2of the photonic resonator, intensities and other characteristics of ambient RF fields (RF signal F) and other microwave fields within the microwave resonator100can be determined. Additionally, using the fiber optic, laser light L, and a photo-optic reader component810, the RF signals within resonator100can be transduced to the optical domain and interpreted and read in the optical domain by reader810(see path808). A similar configuration can be used on microwave fields near the resonator member202of the microwave resonator200to determine characteristics of fields in a single disk resonator.

When the resonator100or200is confined within an enclosure, the resonator can be shielded by outside magnetic, electromagnetic, RF, or electric fields. Because no perturbations or disturbances affect the resonator when inside the enclosure, a resonator inside an enclosure can provide a highly accurate measuring device for determining intensity of microwave fields or other characteristics inside of the resonator.

Another effect that can be utilized in microwave resonators according to the principles described herein is that magnetic fields and electric fields can be used together or separate to enhance the microwave field in the microwave resonator. For example, a material such as a quantum capable material like silicon carbide or vacancy doped diamond can be used in the microwave resonators and disposed in the spatial interaction region106. The vacancy doped diamond can be formed in a thin film and placed in the spatial interaction region106. The vacancy doped diamond film can at least partially fill, or completely fill the volume of the spatial interaction region106.

The vacancy doped diamond with nitrogen vacancy (NV) centers have microwave transition frequencies that are sensitive to an applied magnetic field. Accordingly, with vacancy doped diamond disposed in the spatial interaction region106of the microwave resonator, a magnetic field can be applied to the microwave resonator. As shown inFIG.9A, one or more magnets902and/or904can be placed in proximity to the microwave resonator100to apply a magnetic field in a microwave resonator system900A. It will be appreciated that one or more magnets can similarly be applied to induce a magnetic field on any microwave resonator according to the principles described herein, such as microwave resonator200, in a microwave resonator system900B as shown inFIG.9B.

As shown inFIG.9A, the microwave frequency of the vacancy doped diamond with NV center can be tuned based on the position and strength of the magnets902and/or904. If the microwave resonator100has a resonant frequency equal to the microwave frequency of the vacancy doped diamond906, the microwave signal in the microwave resonator100is enhanced.

The magnets902and/or904can act as static magnetic field SMF on the microwave resonator100. In addition to the static magnetic field SMF provided by magnets902and/or904, any external magnetic fields EMF acting on the microwave resonator100can change the microwave frequency of the vacancy doped diamond906to deviate from the expected frequency due to the static magnetic field SMF applied by the magnets902and/or904. Sensing, measuring, and or calculating of the deviation of the microwave frequency of the vacancy doped diamond906can provide data needed to allow for sensing and/or calculating of the external magnetic field EMF. To excite the microwave frequency of the vacancy doped diamond906, a laser light such as a 532 nm laser or red laser may be needed to excite the NV center of the vacancy doped diamond906.

In an alternative configuration, two or more electrical conductors can replace, or be used in addition to the magnets902and904to induce an electrical field on the microwave resonator100that augments the microwave field in the resonator. In similar fashion to the magnetic embodiment ofFIG.9A, the known electrical field applied between two electrodes to the resonator can be used to measure and quantify an external electrical field.

When the resonator100or200is confined within an enclosure, the resonator can be shielded by outside magnetic, electromagnetic, RF, or electric fields. Because no perturbations or disturbances affect the resonator when inside the enclosure, a resonator inside an enclosure can provide a highly accurate measuring device for determining intensity of microwave fields or other characteristics inside of the resonator.

Additional configurations will be discussed for microwave resonator systems900C and900D as shown inFIGS.9C and9D. As illustrated inFIG.9C, a single disk microwave resonator901C can be mounted between two magnets902and904to apply a magnetic field to the resonator901C inside an enclosure960. In this configuration, light from a laser light source LS outside of enclosure960can be applied to the microwave resonator901C to mix optical light with the RF signal resonating in the resonator for purposes described above with respect to the discussion ofFIG.8. Light from the laser light source LS can be delivered via an optical fiber F to the resonator901C. The resonator can comprise a resonator member920. The resonator member920can comprise a layer of a first material922, (e.g. vacancy doped diamond). The resonator member can further comprise a layer of a second material924(e.g. SiO2 of a thickness of hundreds nanometers to 1 micron) disposed on the first material922. A spiral waveguide928(made of SiN for example, or any material suitable for a waveguide in a microwave resonator) can be patterned on the second material924that starts at a center of the second material924and spirals outward to the perimeter of the resonator901C. The waveguide928can be cladded in a layer of SiO2. However, the disclosure does not intend to limit the shape or material of the waveguide928to those shapes and materials recited.

At the entrance the waveguide928a grating coupler926can be formed of the waveguide material and may taper in shape to capture the laser light and direct it into the waveguide928. By this configuration, the grating coupler926can facilitate guiding of light from the laser light source LS and the fiber F to enter the waveguide928. In the spiral configuration shown, light in the waveguide926spirals closer to a perimeter of the resonator member920where the microwave field of the microwave resonator901C is at a higher intensity. The laser light from the from the waveguide928can leak to the first material922layer and generate a microwave signal which is in resonance with the resonant frequency of the microwave resonator901C. The mixed signals can be used, as described in reference toFIG.8, to measure and/or isolate different signals in the resonator901C

An RF control circuit can supply and/or receive the RF signals to/from the microwave resonator901C. A pair of RF probes RFP1and RFP2can be in wave communication with the resonator901C to receive or transmit RF signals. The probes RFP1and RFP2can be in wave, radio, or electrical communication with an RF source RFS that can supply an RF signal and an RF control RFC that can alter an RF signal (e.g. a phase shifter, amplifier, filter, etc.). An RF signal can be output from the RF source based on the output of the resonator and the RF control for analysis or measurement.

Similarly, a dual disk resonator can work in a similar configuration to system900C.FIG.9Dillustrates a dual disk resonator system900D including a dual disk resonator901D. As illustrated inFIG.9D, a dual disk microwave resonator901D can be mounted between two magnets902and904to apply a magnetic field to the resonator901D inside an enclosure960. In this configuration, light from a laser light source LS outside of enclosure960can be applied to the microwave resonator901D to mix optical light with the RF signal resonating in the resonator for purposes described above with respect to the discussion ofFIG.8. Light from the laser light source LS can be delivered via an optical fiber F to the resonator901D. The resonator can comprise a first resonator member932and a second resonator member934. The first and second resonator members932and934can comprise dielectric materials as described elsewhere in this disclosure similar to the resonator members of resonator100. The spatial interaction region936of the resonator901D can include a layer of a first material938, (e.g. vacancy doped diamond). The resonator member can further comprise a layer of a second material940(e.g. SiO2of a thickness of hundreds nanometers to 1 micron) disposed on the first material938. A spiral waveguide944(made of SiN for example, or any material suitable for a waveguide in a microwave resonator) can be patterned on the second material940that starts at a center of the second material940and spirals outward to the perimeter of the resonator901D. The waveguide944can be cladded in a layer of SiO2. However, the disclosure does not intend to limit the shape or material of the waveguide944to those shapes and materials recited.

At the entrance the waveguide944a grating coupler942can be formed of the waveguide material and may taper in shape to capture the laser light and direct it into the waveguide944. An additional layer or third material946can cover the waveguide944and the grating coupler942in the spatial interaction region936.

In this configuration, the waveguide944and the grating coupler942can be embedded in the spatial interaction region936of the resonator901D. To guide light to the grating coupler942, a microlens950can be disposed on the end of the optical fiber F to collimate light into the grating coupler942from the fiber F. The grating coupler942can facilitate guiding of light from the microlens950to enter the waveguide944. In the spiral configuration shown, light in the waveguide944spirals closer to a perimeter of the spatial interaction region936where the microwave field of the microwave resonator901D is at a higher intensity. From there, the laser light from the from the waveguide944can leak to the first material938layer and generate a microwave signal which is in resonance with the resonant frequency of the microwave resonator901D. The mixed signals can be used, as described in reference toFIG.8, to measure and/or isolate different signals in the resonator901D

Similar to system900C, an RF control circuit can supply and/or receive the RF signals to/from the microwave resonator901D of system900D. A pair of RF probes RFP1and RFP2can be in wave communication with the resonator901D to receive or transmit RF signals. The probes RFP1and RFP2can be in wave, radio, or electrical communication with an RF source RFS that can supply an RF signal and an RF control RFC that can alter an RF signal (e.g. a phase shifter, amplifier, filter, etc.). An RF signal can be output from the RF source based on the output of the resonator and the RF control for analysis or measurement.

Additionally, although not shown, in both systems900C and900D, a temperature controller can be included to stabilize the temperature of the system900D and900C, in and/or out of the enclosures960in order to ensure a desirable operating temperature for detecting, analyzing, and/or measuring signals from the resonators901C and901D.

Further disclosed herein is a method1000of facilitating formation of a microwave resonator device. The method1000is illustrated inFIG.10. The method1000can include step1002of configuring a first resonator member to be comprised of a dielectric material. The method1000can further include step1004of configuring a second resonator member comprised of a dielectric material to be spatially offset from the first resonator member to define a spatial interaction region between the first resonator member and the second resonator member configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum. The method can further comprise a step1006of configuring the microwave resonator to comprise a resonance enhancement factor of 10{circumflex over ( )}3 or greater. The resonance enhancement factor determining the resonant field enhancement can be based on one or more of: a volume of the spatial interaction region; a height of the spatial interaction region; a lateral dimension of the spatial interaction region; thicknesses of the resonator members; and/or a dielectric constant of the dielectric material used for the resonator members.

In the method1000, the spatial offset between the first resonator member and the second resonator member defining the spatial interaction region can be less than a microwave wavelength associated with a resonant frequency of the microwave resonator device. Additionally, the microwave resonator device can facilitate generation of a resonant field enhancement within the spatial interaction region.

The method can further comprise configuring an enclosure to comprise a wall that defines an inner cavity within the enclosure. The method can further comprise mounting first resonator member and the second resonator member to the wall of the enclosure within the inner cavity to be disposed spaced apart from each other to define the spatial interaction region between the first and second resonator members. The method can further comprise configuring the spatial interaction region to comprise one or more of: a vacuum between the first resonator member and the second resonator member, a gas material of lower dielectric constant than is used in the first resonator member and the second resonator member, a solid material of lower dielectric constant than is used in the first resonator member and the second resonator member, and/or a liquid material of lower dielectric constant than is used in the first resonator member and the second resonator member.

Further disclosed herein is a method1100of facilitating formation of a microwave resonator device. The method1100can include a step1102of configuring a resonator member that is configured to confine an electromagnetic field in a microwave region of the electromagnetic spectrum to comprise a thickness measured in a direction parallel to a longitudinal axis of the resonator member. The method can further comprise a step1104of configuring the thickness of the resonator member to be smaller than a microwave wavelength associated with a resonant frequency of the microwave resonator device. The microwave resonator device can facilitate generation of a resonant field enhancement within and in proximity to the resonator member. The method can further comprise a step1106of configuring the microwave resonator to comprise a resonance enhancement factor of 103or greater. The resonance enhancement factor determining the resonant field enhancement can be based on one or more of: a volume of the resonator member; a lateral dimension of the resonator member; a thickness of the resonator member; and/or a dielectric constant of the dielectric material used for the resonator member. The method1100can further comprise configuring an enclosure to comprise a wall that defines an inner cavity within the enclosure. The method1100can further comprise mounting the resonator member to the wall of the enclosure within the inner cavity.

Although the disclosure may not expressly disclose that some embodiments or features described herein may be combined with other embodiments or features described herein, this disclosure should be read to describe any such combinations that would be practicable by one of ordinary skill in the art. The use of “or” in this disclosure should be understood to mean non-exclusive or, i.e., “and/or,” unless otherwise indicated herein.