Various emitters and emitter systems are disclosed. For instance, in various embodiments, an emitter can comprise a substrate, an insulator bonded to the substrate, a graphene layer bonded to the insulator, and a first electrical contact and a second electrical contact. The first electrical contact can be bonded over a first portion of the graphene layer, and the second electrical contact can be bonded over a second portion of the graphene layer. The graphene layer electrically couples the first electrical contact and the second electrical contact and is configured to receive the application of a pulsed input voltage between the first electrical contact and the second electrical contact and to radiate radio frequency (RF) energy. An emitter system can comprise a plurality of emitters, each disposed on a single integrated circuit.

BACKGROUND

The present disclosure generally relates to solid state nanoscale radio frequency (RF) emitters.

2. Discussion of the Related Art

A variety of applications and devices may benefit from the use of one or more precise and stable high frequency emitters. Examples of such applications and devices include ultra-high speed computers, high precision scanners, radars, radio frequency detectors, and applications configured to record images observed through RF-opaque objects without the use of ionizing radiation.

Conventionally, emitters operating at frequencies of about 300 gigahertz have not been extremely well stabilized in their frequency response. However, higher frequency, stable, output radiation is desirable, and with the advent of graphene, the design of an emitter configured, as disclosed herein, to operate in the frequency range of about 300 gigahertz to 3 terahertz has become possible. A stable high frequency gigahertz and/or terahertz emitter, as disclosed herein, is therefore desirable.

SUMMARY

In various embodiments, various emitters and emitter systems are disclosed. For instance, in various embodiments, an emitter can comprise a substrate, an insulator bonded to the substrate, a graphene layer bonded to the insulator, a first electrical contact, and a second electrical contact. The first electrical contact can be bonded over a first portion of the graphene layer, and the second electrical contact can be bonded over a second portion of the graphene layer. The graphene layer electrically couples the first electrical contact and the second electrical contact and is configured to receive the application of a pulsed input voltage between the first electrical contact and the second electrical contact and to radiate radio frequency (RF) energy. An emitter system can comprise a plurality of emitters, each disposed on a single integrated circuit.

Moreover, in various embodiments, an emitter can comprise a substrate, an insulator bonded to the substrate, a graphene layer bonded to the insulator, a first electrical contact, a second electrical contact, and a photoelectric element. The first electrical contact can be bonded over a first portion of the graphene layer, and the second electrical contact can be bonded over a second portion of the graphene layer. The graphene layer electrically couples the first electrical contact and the second electrical contact and is configured to receive the application of a DC bias voltage between the first electrical contact and the second electrical contact. The emitter can be configured to supply a pulsed burst of photoelectric energy (electrons) to the graphene layer in response to light shining upon the photoelectric element, which can cause the emitter to radiate RF energy.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

It is to be understood that the description above and the following detailed description are exemplary and explanatory only and are not to be viewed as being restrictive of the invention, as claimed. Further advantages of this invention will be apparent after a review of the following detailed description of the disclosed embodiments, which are illustrated schematically in the accompanying drawings and in the appended claims.

In accordance with various embodiments, a solid state nanoscale RF emitter is generally disclosed. In some instances, embodiments of the invention may also be referred to as a planar graphene semi-cyclotron(s). A person having ordinary skill in the art will recognize that a cyclotron is a type of particle accelerator that typically employs two semicircle electrodes. However, embodiments of the invention, employ embodiments using a single half circle electrode.

The emitter may be configured to oscillate in the range of about 300 gigahertz (GHz) to 3 terahertz (THz). In various embodiments, the emitter can comprise a semicircular or semi-annular emitter. As described in additional detail below, the emitter comprises a graphene layer through which electrons can travel. As electrons travel through the graphene layer, the emitter radiates energy in a direction that is substantially normal to the direction of travel by the electrons. An externally applied magnetic (and/or electromagnetic) field can, in some embodiments, be applied to the emitter to control the trajectory taken be electrons in the graphene layer and thereby the frequency of the energy radiated by the emitter (i.e., the emitter output).

The solid state nanoscale emitter can therefore, as disclosed herein, operate as a precise (output signal frequency regulated) and stable (output signal waveform regulated) gigahertz and/or terahertz radio frequency emitter. The emitter may be useful for a variety of applications, such as, for example, applications related to ultra-high speed computers, high precision scanners, RADAR(s), RF detectors, antennas, pulse generators, scanning devices, applications requiring an emitter for imaging through opaque objects without the use of ionizing radiation, and the like.

The emitter is depicted in the figures as being surrounded by air, also sometimes referred to as free space. Other surrounding materials such as, for example, water or oil, may also be used depending on application specific-conditions. The various embodiments disclose material layers that are associated with adjacent layers by bonding. It is understood that bonding includes any of the various bonding methods known to those having ordinary skill in the art, including, but not limited to mechanical bonding, chemical bonding, van der Waals bonding, heat bonding, pressure bonding, dipole interaction bonding, and/or ionic bonding.

Embodiments disclose semiconductor materials, such as semiconductor substrates. A semiconductor substrate may comprise any suitable semiconductor material such as, for example, any silicon, class III-V semiconductors, class II-VI semiconductors, binary semiconductors, ternary semiconductors, and/or organic semiconductors.

Embodiments further disclose graphene layers. It is understood that graphene is a material that is more than 95 percent carbon by weight and includes at least one, one-atom-thick planar layer comprised of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice and held together by strong van der Waals forces. The graphene material may contain one layer of carbon atoms or a plurality of layers of carbon atoms.

Accordingly, and with reference now toFIG. 1, a perspective view of a solid state nanoscale emitter100is shown. The emitter100comprises a substrate102, an insulator104bonded to the substrate102, a graphene layer106bonded to the insulator104, a first electrical contact108, and a second electrical contact110. The first electrical contact108is, in various embodiments, bonded over a first portion112of the graphene layer106. Similarly, the second electrical contact110is, in various embodiments, bonded over a second portion114of the graphene layer106.

The graphene layer106electrically couples the first electrical contact108to the second electrical contact110. The graphene layer106is further configured to receive the application of a pulsed and/or DC bias input voltage between the first electrical contact108and the second electrical contact110. As discussed in greater detail below, the graphene layer106radiates RF energy, in response to the pulsed input voltage, in a direction that is substantially normal to the direction in which electrons travel in the graphene layer106.

As shown, the graphene layer106can comprise a semicircular portion116. The semicircular portion116may be defined as a substantially planar annulus having an inner radius118and an outer radius120, where the inner radius118and the outer radius120together define the width122of the annulus. The graphene layer106can further comprise each of the first portion112and the second portion114, both of which can extend away from the semicircular portion116in substantially straight lines. Thus, the graphene layer106comprises, in various embodiments, a “U” or “horseshoe” shape, which may also be referred to as “substantially U-shaped” or “substantially horseshoe-shaped.”

The “legs,” or first portion112and the second portion114, can extend to any suitable length. Likewise, the graphene layer106can be constructed to any suitable width122, and the inner radius118and outer radius122can be of any suitable measurement. For example, as shown inFIG. 2, the inner radius can measure 95 nanometers, and the outer radius can measure 955 nanometers. However, any other radial measurements in the range of 95 nanometers to 955 nanometers are contemplated by and within the scope of this disclosure. In addition, the width122of the graphene layer106can comprise any measurement in the range of 300 nanometers to 870 nanometers, and the length of the first portion112and second portion114of the graphene layer106can, in various embodiments, extend to any length in the range of 580 nanometers to 1740 nanometers.

With reference now toFIG. 3, a cross-sectional view of a solid state nanoscale emitter100is shown. The cross-section shown is perpendicular to the cut plane3-3, as shown inFIG. 2. The substrate102, insulator104, graphene layer106, first electrical contact108, and second electrical contact110are shown. In addition, a cut-out or close-up section4is defined. In various embodiments, the substrate102can comprise any suitable substrate, such as, for example, silicon (Si) and can comprise any suitable thickness. Further, in various embodiments, the insulator104can comprise any suitable insulating material, such as, for example, silicon dioxide (SiO2) and can be any suitable thickness. Suitable thickness of the insulator104can be in the range of about 100 nanometers to about 500 nanometers.

With attention toFIG. 4, the cutout section4, illustrating a portion of the cross-sectional view of the solid state nanoscale emitter100, is shown. As depicted, in various embodiments, the second electrical contact110can comprise gold (Au) and can be about 40 nanometers in thickness. The second electrical contact110can overlay and/or be bonded over a layer of palladium (Pd)124that is about 10 nanometers in thickness. Moreover, and in various embodiments, the layer of palladium124can overlay and/or be bonded to a layer of titanium (Ti)126that is about 0.5 nanometers in thickness, and the layer of titanium126can overlay and/or be bonded to the graphene layer106, which can, as discussed elsewhere herein, overlay and/or be bonded to the insulator104, which can overlay and/or be bonded to the substrate102. Although not shown in identical detail, the same construction can apply to the first electrical contact108.

In operation, and with returning reference now toFIG. 1, an input voltage can be applied (e.g., by a voltage source) between the first electrical contact108and the second electrical contact110. The voltage source is not shown in the figures since voltage sources are well known. The input voltage can be intermittent, or pulsed, such that a voltage between the first electrical contact108and the second electrical contact110is developed for a period of time, reduced (e.g., to a zero or substantially zero voltage) for a period of time, developed again for a period of time, reduced for a period of time, and so on in an “on” and “off” or “high” and “low” pattern for any suitable duration. As the input voltage is pulsed high, electrons (comprising an electrical current) travel within the graphene layer106from the first contact108towards the second contact110. As electrons travel within the graphene layer106, an electromagnetic field is generated normal to the direction of travel of each electron. Thus, as each electron travels within the substantially planar graphene layer106, an electromagnetic field is generated substantially normal to the plane defined by the graphene layer106(i.e., in the case ofFIG. 1, “out of the page”). In other words, although each electron travels along the radius of the arc defined by the semicircular portion116of the graphene layer106, each electron generates an electromagnetic field that is normal to its two-dimensional direction of travel—i.e., normal to the plane defined by the semicircular portion116of the graphene layer106.

The frequency of the output signal generated by the emitter100as electrons travel through the graphene layer106is dependent upon the radius of the arc taken by electrons as they travel. In general, a smaller radius of travel results in a higher frequency output signal, while a larger radius of travel results in a lower frequency output signal. For example, where electrons travel through the graphene layer106along the outer radius120, the output signal can have a frequency of about 300 gigahertz, while electrons traveling along the inner radius118can generate an output signal having a frequency of about 3 terahertz. Electrons traveling between the inner radius118and outer radius120can generate output signals having frequencies in the range of 300 gigahertz to 3 terahertz.

Therefore, as shown with respect toFIG. 5, the frequency of the signal output by the emitter100can be adjusted or “tuned” by the application of a (varying or variable) magnetic and/or electromagnetic field502to the emitter100. More particularly, a magnetic field502can, in various embodiments, be applied to the graphene layer106such that, as electrons travel through the graphene layer106, their trajectories are influenced by the magnetic field502. For example, the magnetic field502can be applied over a range of field strengths, such that electrons travel along a particular radius within the graphene layer106. Therefore, as described above, as electrons are guided towards the outer radius120, the frequency of the output signal can be reduced, while as electrons are guided towards the inner radius118, the frequency of the output signal can be increased. Thus, the frequency of the output signal can be tuned through the use of the magnetic field502to any suitable value in the range of 300 gigahertz and 3 terahertz. The magnetic field strength can range, in various embodiments, from 0.105 Teslas to 0.262 Teslas.

With brief reference toFIG. 6, an example timing diagram of an example input signal602and an example output signal604are depicted. As shown, and as described above, the input signal602can comprise a pulsed voltage, or a square wave. In various embodiments, as the square wave peaks (or goes high), the emitter100can generate a sinusoidal output signal604that decays in amplitude over time. In other words, the emitter100can generate a series of sinusoidal outputs604that decay in amplitude over time. The output signal604further oscillates in frequency, as described herein, according to field strength of the magnetic field502in the range of 300 gigahertz to 3 terahertz. Thus, the emitter100is capable of generating a very stable, very well-modulated, output signal604.

In various embodiments, a plurality of emitters100can be disposed or manufactured as part of a single integrated circuit. For instance, in some embodiments, an integrated circuit can include about 60 million emitters100. This number of emitters can be spread out over an integrated circuit space that is about 16 inches square in area. Thus, in operation, the RF energy radiated by each emitter100on the integrated circuit can add by a process of linear superposition during transmission (e.g., transmission through free space), resulting in a combined signal having a much greater strength than the strength of any individual signal generated by a particular emitter100.

With attention now toFIG. 7, a perspective view of a solid state nanoscale emitter700having a plurality of photoelectric elements is shown. Like emitter100, the emitter700can comprise a substrate702, an insulator704bonded to the substrate702, a graphene layer706bonded to the insulator704, a first electrical contact708bonded over a first portion710of the graphene layer706, and a second electrical contact712bonded over a second portion714of the graphene layer706.

The emitter700further comprises a plurality of photoelectric elements716,718, and720. In various embodiments, any number of photoelectric elements can be employed. The photoelectric elements716,718, and720can comprise any elements that receive light energy and radiate, in response, electrons. In other words, a photoelectric element716,718, and720converts received light energy to radiated electrons. The photoelectric elements716,718, and720can be bonded to or otherwise mounted over an extended portion722of the graphene layer706.

Like the graphene layer106of emitter100, the graphene layer706of emitter700electrically couples the first electrical contact708to the second electrical contact712. The graphene layer706is further configured to receive the application of a DC bias voltage between the first electrical contact708and the second electrical contact712. In various embodiments, the DC bias voltage is a steady (or substantially steady) voltage. As discussed in greater detail herein, the graphene layer706radiates RF energy, in response to a pulsed supply of photoelectrically generated electrons, in a direction that is substantially normal direction in which electrons travel in the graphene layer706.

As shown, the graphene layer706can comprise a semi-annular or semicircular portion724. The semicircular portion724may be defined as a substantially planar annulus having an inner radius726and an outer radius728, where the inner radius726and the outer radius728together define the width730of the annulus. The graphene layer706can further comprise the extended portion722(which includes the first portion710over which the first electrical contact708is mounted) and the second portion714, both of which can extend away from the semicircular portion724in substantially straight lines. Thus, the graphene layer706comprises, in various embodiments, a “candy cane” shape.

The “legs,” or extended portion722and the second portion714, can extend to any suitable length. Likewise, the graphene layer706can be constructed to any suitable width730, and the inner radius726and outer radius728can be of any suitable measurement. For example, as shown atFIG. 8, the inner radius726can measure 95 nanometers, and the outer radius728can measure 955 nanometers. However, any other radial measurements in the range of 95 nanometers to 955 nanometers are contemplated by and within the scope of this disclosure. In addition, the width730of the graphene layer706can comprise any measurement in the range of 290 nanometers to 860 nanometers. The length of the first portion710and second portion714of the graphene layer706can, in various embodiments, extend to any length in the range of 580 nanometers to 1740 nanometers, while the extended portion722can measure in the range of 1000 nanometers to 3100 nanometers. The width of the first electrical contact708and second electrical contact712can comprise any measurement in the range of 300 nanometers to 870 nanometers. A photoelectric element716,718, or720can extend along the graphene layer706within the range of 400 nanometers to 1000 nanometers, and each photoelectric element716,718, and720can be separated from an adjacent photoelectric element by 50 nanometers to 100 nanometers.

With reference now toFIG. 9, a cross-sectional view of a solid state nanoscale emitter700having a plurality of photoelectric elements is shown. The cross-section shown is perpendicular to the cut plane9-9, as shown atFIG. 8. The substrate702, insulator704, graphene layer706, and first electrical contact708are shown. In addition, a close-up or cutout section10is defined. In various embodiments, the substrate702can comprise any suitable substrate, such as, for example, silicon (Si) and can comprise any suitable thickness. Further, in various embodiments, the insulator704can comprise any suitable insulating material, such as, for example, silicon dioxide (SiO2) and can be any suitable thickness. Suitable thickness of the insulator704can be in the range of about 100 nanometers to about 500 nanometers.

With attention toFIG. 10, the cutout section10, illustrating a portion of the cross-sectional view of the solid state nanoscale emitter700, is shown. As depicted, in various embodiments, the first electrical contact708can comprise gold (Au) and can be about 40 nanometers in thickness. The contact708can overlay and/or be bonded over a layer of palladium (Pd)1002that is about 10 nanometers in thickness. Moreover, and in various embodiments, the layer of palladium1002can overlay and/or be bonded to a layer of titanium (Ti)1004that is about 0.5 nanometers in thickness, and the layer of titanium1004can overlay and/or be bonded to the graphene layer706, which can, as discussed elsewhere herein, overlay and/or be bonded to the insulator704, which can in turn overlay and/or be bonded to the substrate702. Although not shown in identical detail, the same construction can apply to the second electrical contact712.

In operation, and with returning reference now toFIG. 7, a DC bias input voltage can be applied (e.g., by a voltage source) between the first electrical contact708and the second electrical contact712. Further, light (e.g., laser light) can be intermittently shined on one or more of the photoelectric elements716,718, and720. As light is incident on any of the photoelectric elements716,718, and720, the photoelectric elements can be excited to radiate electrons on the graphene layer706, over which the photoelectric elements716,718, and720are disposed. Thus, electrons can be injected by the photoelectric elements716,718, and720for a period of time, reduced (e.g., to zero or substantially zero) for a period of time, injected again for a period of time, reduced for a period of time, and so on in an “on” and “off” or “high” and “low” pattern for any suitable duration. As the electrons are injected into the graphene layer706, each electron travels from the first contact708towards the second contact712in accordance with the DC bias voltage between the first contact708and the second contact712. Accordingly, as electrons travel within the graphene layer706, an electromagnetic field is generated normal to the direction of travel of each electron. Thus, as each electron travels within the substantially planar graphene layer706, an electromagnetic field is generated substantially normal to the plane defined by the graphene layer706(i.e., in the case ofFIG. 7, “out of the page”). In other words, although each electron travels along the radius of the arc defined by the semicircular portion724of the graphene layer706, each electron generates an electromagnetic field that is normal to its two-dimensional direction of travel—i.e., normal to the plane defined by the semicircular portion724of the graphene layer706.

As described above with reference to emitter100, the frequency of the output signal generated by the emitter700as electrons travel through the graphene layer706is dependent upon the radius of travel taken by electrons. In general, a smaller radius of travel results in a higher frequency output signal, while a larger radius of travel results in a lower frequency output signal. For example, where electrons travel through the graphene layer706along the outer radius728, the output signal can have a frequency of about 300 gigahertz, while electrons traveling along the inner radius726can produce an output signal having a frequency of about 3 terahertz. Electrons traveling between the inner radius726and outer radius726can produce output signals having frequencies in the range of 300 gigahertz to 3 terahertz.

Therefore, as shown with respect toFIG. 11, the frequency of the signal output by the emitter700can be adjusted or tuned by the application of a (varying or variable) magnetic and/or electromagnetic field1102to the emitter700. More particularly, a magnetic field1102can, in various embodiments, be applied to the graphene layer706such that, as electrons travel through the graphene layer706, their trajectories are influenced by the magnetic field1102. For example, the magnetic field1102can be applied over a range of field strengths, such that electrons travel along a particular radius within the graphene layer706. Therefore, as described above, as electrons are guided toward the outer radius728, the frequency of the output signal can be reduced, while as electrons are guided toward the inner radius726, the frequency of the output signal can be increased. Thus, the frequency of the output signal can be tuned through the use of the magnetic field1102to any suitable value in the range of 300 gigahertz and 3 terahertz. The magnetic field1102strength can range, in various embodiments, from 0.105 Teslas to 0.262 Teslas.

Thus, the emitter700can generate, in response to a pulsed supply of photoelectrically generated electrons by one or more photoelectric elements716,718, and720, a sinusoidal output signal that decays in amplitude over time. In other words, the emitter700can generate a series of sinusoidal outputs that decay in amplitude over time. The output signal further oscillates in frequency, as described herein, according to field strength of the magnetic field1102in the range of 300 gigahertz to 3 terahertz. Thus, the emitter700is capable of generating a very stable, very well-modulated output signal604.

In various embodiments, a plurality of emitters700can be disposed or manufactured as part of a single integrated circuit. For instance, in some embodiments, an integrated circuit can include about 60 million emitters700. These emitters can be spread out over a planar integrated circuit space that is 16 inches square in area. Thus, in operation, the RF energy radiated by each emitter700on the integrated circuit can add by a process of linear superposition during transmission (e.g., transmission through free space), resulting in a combined signal having a much greater strength than the strength of any individual signal generated by a particular emitter700.

With attention now toFIG. 12, a perspective view of a solid state nanoscale emitter1200having a plurality of apexed photoelectric elements is shown. Like emitters100and700, the emitter1200can comprise a substrate1202, an insulator1204bonded to the substrate1202, a graphene layer1206bonded to the insulator1204, a first electrical contact1208bonded over a first portion1210of the graphene layer1206, and a second electrical contact1212bonded over a second portion1214of the graphene layer1206.

The emitter1200further comprises a plurality of apexed photoelectric elements1216,1218, and1220. In various embodiments, any number of apexed photoelectric elements can be employed. The apexed photoelectric elements1216,1218, and1220can comprise any elements that receive light energy and radiate, in response, electric (or “photoelectric”) energy. In other words, the apexed photoelectric elements1216,1218, and1220convert received light energy to radiated electrons. The apexed photoelectric elements1216,1218, and1220can be bonded to or otherwise mounted over an extended portion1222of the graphene layer1206.

Like the graphene layers discussed elsewhere herein, the graphene layer1206of emitter1200electrically couples the first electrical contact1208to the second electrical contact1212. The graphene layer1206is further configured to receive the application of a DC bias voltage between the first electrical contact1208and the second electrical contact1212. In various embodiments, this is not a pulsed input voltage, as applied to emitter100; rather, it is a steady (or substantially steady) DC bias voltage. As discussed in greater detail herein, the graphene layer1206radiates RF energy, in response to a pulsed supply of photoelectrically generated electrons, in a direction that is substantially normal to the direction in which electrons travel in the graphene layer1206.

As shown, the graphene layer1206can comprise a semi-annular or semicircular portion1224. The semicircular portion1224may be defined as a substantially planar annulus having an inner radius1226and an outer radius1228, where the inner radius1226and the outer radius1228together define the width1230of the annulus. The graphene layer1206can further comprise the extended portion1222(which includes the first portion1210over which the first electrical contact1208is mounted) and the second portion1214, both of which can extend away from the semicircular portion1224in substantially straight lines. Thus, the graphene layer1206comprises, in various embodiments, a “candy cane” shape.

The “legs,” or extended portion1222and the second portion1214, can extend to any suitable length. Likewise, the graphene layer1206can be constructed to any suitable width1230, and the inner radius1226and outer radius1228can be of any suitable measurement. For example, as shown atFIG. 13, the inner radius1226can measure 95 nanometers, and the outer radius1228can measure 955 nanometers. However, any other radial measurements in the range of 95 nanometers to 955 nanometers are contemplated by and within the scope of this disclosure. In addition, the width1230of the graphene layer1206can comprise any measurement in the range of 290 nanometers to 860 nanometers. The length of the first portion1210and second portion1214of the graphene layer1206can, in various embodiments, extend to any length in the range of 580 nanometers to 1740 nanometers, while the extended portion1222can measure in the range of 1000 nanometers to 3100 nanometers. The width of the first electrical contact1208and second electrical contact1212can comprise any measurement in the range of 300 nanometers to 870 nanometers. The apexed photoelectric elements1216,1218, and1220can extend along the graphene layer1206within the range of 400 nanometers to 1000 nanometers, and each apexed photoelectric elements1216,1218, and1220can be separated from an adjacent apexed photoelectric element by 50 nanometers to 100 nanometers (as between adjacent apexes).

An apexed photoelectric element1216,1218, and1220can include an apexed or apexed edge, as shown, as a means of shedding excess heat. That is, an apexed photoelectric element1216,1218, and1220can, because it has greater surface area than, for example, a rectangular photoelectric element, shed greater thermal energy than such an element. Thus, in various embodiments, such as where the apexed photoelectric elements1216,1218, and1220are being loaded with thermal energy by a laser, such apexed photoelectric elements1216,1218, and1220can be utilized to help shed excess thermal energy and so to cool the emitter1200during operation. In various embodiments, any other shape of photoelectric element may be used to regulate thermal energy, according, for example, to the energy radiated by the photoelectric element in conjunction with the thermal dissipation requirements associated with the emitter to which the photoelectric element is coupled.

With reference now toFIG. 14, a cross-sectional view of a solid state nanoscale emitter700having a plurality of apexed photoelectric elements is shown. The cross-section shown is perpendicular to the cut plane14-14, as shown atFIG. 13. The substrate1202, insulator1204, graphene layer1206, and first electrical contact1208are shown. In addition, a close-up view or cutout section15is defined. In various embodiments, the substrate1202can comprise any suitable substrate, such as, for example, silicon (Si) and can comprise any suitable thickness. Further, in various embodiments, the insulator1204can comprise any suitable insulating material, such as, for example, silicon dioxide (SiO2) and can be any suitable thickness, such as, for example, any thickness in the range of 100 nanometers to 500 nanometers.

With attention toFIG. 15, the cutout section15, illustrating a portion of the cross-sectional view of the solid state nanoscale emitter1200, is shown. As depicted, in various embodiments, the first electrical contact1208can comprise gold (Au) and can be about 40 nanometers in thickness. The contact1208can overlay and/or be bonded over a layer of palladium (Pd)1502that is about 10 nanometers in thickness. Moreover, and in various embodiments, the layer of palladium1502can overlay and/or be bonded to a layer of titanium (Ti)1504that is about 0.5 nanometers in thickness, and the layer of titanium1504can overlay and/or be bonded to the graphene layer1206, which can, as discussed elsewhere herein, overlay and/or be bonded to the insulator1204, which can in turn overlay and/or be bonded to the substrate1202. Although not shown in identical detail, the same construction can apply to the second electrical contact1212.

With brief regard toFIG. 16, a close-up or cutout section16(as defined atFIG. 15) illustrating a portion of the cross-sectional view of the solid state nanoscale emitter1200, is shown. The cutout section16illustrates, in greater detail, the apexed photoelectric element1218. As shown, the apexed photoelectric element1218(as well as the other apexed photoelectric elements1216and1220) can comprise a width in the range from 100 nanometers to 870 nanometers. Likewise, each of the apexed photoelectric elements1216,1218, and1220can comprise a length in the range of 400 nanometers to 1000 nanometers (from apex to apex).

In operation, and with returning reference now toFIG. 12, a DC bias input voltage can be applied (e.g., by a voltage source) between the first electrical contact1208and the second electrical contact1212. Further, light (e.g., laser light) can be intermittently shined on one or more of the photoelectric elements1216,1218, and1220. As light is incident on any of the photoelectric elements1216,1218, and1220, the photoelectric elements can be excited to radiate electrons on the graphene layer1206, over which the photoelectric elements1216,1218, and1220are disposed. Thus, electrons can be injected by the photoelectric elements1216,1218, and1220for a period of time, reduced (e.g., to zero or substantially zero) for a period of time, injected again for a period of time, reduced for a period of time, and so on in an “on” and “off” or “high” and “low” pattern for any suitable duration. As the electrons are injected into the graphene layer1206, each electron travels from the first contact1208towards the second contact1212in accordance with the DC bias voltage between the first contact1208and the second contact1212. Accordingly, as electrons travel within the graphene layer1206, an electromagnetic field is generated normal to the direction of travel of each electron. Thus, as each electron travels within the substantially planar graphene layer1206, an electromagnetic field is generated substantially normal to the plane defined by the graphene layer1206(i.e., in the case ofFIG. 12, “out of the page”). In other words, although each electron travels along the radius of the arc defined by the semicircular portion1224of the graphene layer1206, each electron generates an electromagnetic field that is normal to its two-dimensional direction of travel—i.e., normal to the plane defined by the semicircular portion1224of the graphene layer1206.

The frequency of the output signal generated by the emitter1200as electrons travel through the graphene layer1206is dependent upon the radius of the arc taken by electrons as they travel. In general, a smaller radius of travel results in a higher frequency output signal, while a larger radius of travel results in a lower frequency output signal. For example, where electrons travel through the graphene layer1206along the outer radius1228, the output signal can have a frequency of about 300 gigahertz, while electrons traveling along the inner radius1226can produce an output signal having a frequency of about 3 terahertz. Electrons traveling between the inner radius1226and outer radius1228can produce output signals having frequencies in the range of 300 gigahertz to 3 terahertz.

Therefore, as shown with respect toFIG. 17, the frequency of the signal output by the emitter1200can be adjusted or tuned by the application of a (varying or variable) magnetic and/or electromagnetic field1702to the emitter1200. More particularly, a magnetic field1702can, in various embodiments, be applied to the graphene layer1206such that, as electrons travel through the graphene layer1206, their trajectories are influenced by the magnetic field1702. For example, the magnetic field1702can be applied over a range of field strengths, such that electrons travel along a particular radius within the graphene layer1206. Therefore, as described above, as electrons are guided towards the outer radius1228, the frequency of the output signal can be reduced, while as electrons are guided towards the inner radius1226, the frequency of the output signal can be increased. Thus, the frequency of the output signal can be tuned through the use of the magnetic field1702to any suitable value in the range of 300 gigahertz and 3 terahertz. The magnetic field1702strength can range, in various embodiments, from 0.105 Teslas to 0.262 Teslas.

Thus, as described above with reference to the emitter700, the emitter1200can generate, in response to a plurality of pulsed photoelectric input voltages, a sinusoidal output signal that decays in amplitude over time. In other words, the emitter1200can generate a series of sinusoidal outputs that decay in amplitude over time. The output signal further oscillates in frequency, as described herein, according to field strength of the magnetic field1702in the range of 300 gigahertz to 3 terahertz. Thus, the emitter1200is capable of generating a very stable, highly output signal.

In various embodiments, a plurality of emitters1200can be disposed or manufactured as part of a single integrated circuit. For instance, in some embodiments, an integrated circuit can include about 60 million emitters1200. These emitters can be spread out over a planar integrated circuit space that is about 16 inches square. Thus, in operation, the RF energy radiated by each emitter1200on the integrated circuit can add by a process of linear superposition during transmission (e.g., transmission through free space), resulting in a combined signal having a much greater strength than the strength of any signal produced by a particular emitter1200.

It is apparent that embodiments of the invention are configurable to discriminate frequency and particularly in the terahertz region. The result is highly synchronized terahertz radiation that is predictable and well-regulated. Embodiments of the invention can be stand-alone or included in a layered or matrix orientation as well as two-dimensional or three-dimensional. Embodiments of the invention may also be presented as multiple layer structures fabricated by methods that have demonstrated capability for rapid scale-up for mass production of large area devices.