Surface state gain

A gain medium may be arranged to provide energy to a surface state.

SUMMARY

In one embodiment, an apparatus comprises: a first dielectric boundary region arranged to support a first dielectric surface state; and a first gain medium selected to amplify the first dielectric surface state, wherein the first gain medium is arranged relative to the first dielectric boundary region for amplification of the first dielectric surface state.

In another embodiment, a method comprises: propagating a first dielectric surface state; and passing the first dielectric surface state through a first region, the first region being selected to amplify the first dielectric surface state.

In another embodiment, an apparatus comprises: a first layer including a first medium; a second layer spaced apart from the first layer, the second layer including a first gain medium; and a third layer at least partially interposed between the first layer and the second layer and including a third medium different from the first medium and the first gain medium, wherein the first layer and the third layer form a first boundary supportive of a first propagating surface state, and wherein the first gain medium is configured to evanescently couple to the first surface state.

In another embodiment, an apparatus comprises: a first layer including a first medium; a third layer including a third medium, wherein the first layer and the third layer form a first boundary supportive of a first propagating surface state; and a second layer spaced apart from the first boundary and including a first gain medium configured to evanescently couple to the first propagating surface state.

In anther embodiment, a method comprises: evanescently providing gain energy to a propagating surface state at a first boundary region including an interface between first and second media, from a third medium spaced apart from the interface and separate from the first and second media.

In another embodiment, an apparatus comprises: a first magnetic boundary region arranged to support a first magnetic surface state; and a first gain medium selected to amplify the first magnetic surface state, wherein the first gain medium is arranged relative to the first magnetic boundary region for amplification of the first magnetic surface state.

In another embodiment, a method comprises: propagating a first magnetic surface state; and passing the first magnetic surface state through a first region, the first region being selected to amplify the first magnetic surface state.

DETAILED DESCRIPTION

A surface state may exist on a boundary between two media when the real parts of their dielectric constants ∈ and ∈′ or the real parts of their permeabilities μ and μ′ and have different signs.FIG. 1shows a surface state102at a boundary104of a first medium106and a second medium108, where the first and second media106,108are selected such that they support the surface state102. The boundary104, although shown as being substantially continuous and planar, may have a different shape. The surface state102, although shown as including substantially exponential functions with a field maximum at the boundary104, may include only approximately exponential functions, may be described by a different function, and/or may have a field maximum someplace other than the boundary. Further, although the surface state102is shown at a certain location on the boundary104for illustrative purposes, the spatial distribution of the surface state102may be anything.

In one embodiment the surface state102may be a plasmon. In this case the medium106is a conductor and the medium108is a dielectric, where the conductor may be a high conductivity metal such as gold or silver, or may be a different conductor. The dielectric forming the boundary104with the conductor may be: air, vacuum, or its equivalent; a substantially homogeneous dielectric material; or a different material or structure. Although the term “plasmon” is used in this illustration to describe a state propagating at the boundary between a conductor and a dielectric, one skilled in the art may recognize that other terms may have been applied to describe such states, including, but not limited to, “surface plasmon” and/or “surface plasmon polariton”.

In some embodiments the material thickness110may be smaller than the plasmon wavelength, as described in Alexandra Boltasseva, Thomas Nikolajsen, Krisjan Leosson, Kasper Kjaer, Morten S. Larsen, and Sergey I. Bozhevolnyi, “INTEGRATED OPTICAL COMPONENTS UTILIZING LONG-RANGE SURFACE PLASMON POLARITONS”, Journal of Lightwave Technology, January, 2005, Volume 23, Number 1, which is incorporated herein by reference. Further, Boltasseva describes how a metal may be embedded in a dielectric to allow propagation of long-range surface plasmon polaritons, where the parameters of the metal (including thickness110) may control the propagation of the plasmon.

In another embodiment, the surface state102may be a magnetic surface state. In this case, the medium106has an effectively negative permeability μ and the medium108has a positive permeability μ′. The medium106having an effectively negative permeability μ may be, for example, a metamaterial. One example of a metamaterial having an effectively negative permeability μ is described in C. Enkrich et al., “MAGNETIC METAMATERIALS AT TELECOMMUNICATION AND VISIBLE FREQUENCIES”, Physical Review Letters, 11 Nov. 2005, Volume 95, pages 203901-1—203901-4, which is incorporated herein by reference. Metamaterials are also described in D. R. Smith et al., “METAMATERIALS AND NEGATIVE REFRACTIVE INDEX”, Science, 6 Aug. 2004, Volume 305, pages 788-792, which is incorporated herein by reference. Metamaterials having a variety of properties may be achieved, including those with negative permittivity ∈.

In another embodiment, the surface state102may be a dielectric surface state. In this case, both media106and108are dielectrics, where one of the dielectrics has a negative, or effectively negative, permittivity.

One example of a dielectric surface state is the case where one of the dielectrics includes a polar dielectric having a Restrahlen band. These dielectrics have a frequency-dependent dielectric permittivity that is negative in a certain frequency range. Examples of polar dielectrics having a Restrahlen band include, but are not limited to, silicon carbide (SiC), lithium tantalate (LiTaO3), lithium fluoride (LiF), and zinc selenide (ZnSe). Polar dielectrics having a Restrahlen band are described in Gennady Shvets, “PHOTONIC APPROACH TO MAKING A MATERIAL WITH A NEGATIVE INDEX OF REFRACTION,” Physical Review B, 16 Jan. 2003, Volume 67, pages 035109-1—035109-8, which is incorporated herein by reference.

Another example of a dielectric surface state is the case where one or both of the dielectrics is a medium having a band gap, such as a photonic crystal. A surface state may exist at the interface between the photonic crystal and the other dielectric in the forbidden energy bands of the photonic crystal. Photonic crystals are described in E. Yablonovitch, “PHOTONIC CRYSTALS: SEMICONDUCTORS OF LIGHT”, Scientific American, December 2001, Volume 285, Number 6, pages 47-55, which is incorporated herein by reference.

Although the embodiments described with respect toFIG. 1refer to the first and second materials106,108, where the first material106is shown below the second material108, generally the first and second materials106,108are interchangeable; that is, the material108may be the bottom layer and the material106may be the top layer. Further, in some embodiments the boundary104may be vertical or may have some other orientation than the horizontal representation ofFIG. 1.

Generally speaking, “boundary region” refers to a region proximate to a boundary. For example, the boundary region ofFIG. 1includes the region, proximate to the boundary104, in the first and second media106,108into which the surface state102extends. A dielectric boundary region may be configured to support a dielectric surface state as previously defined. Similarly, a magnetic boundary region may be configured to support a magnetic surface state as previously defined, etc.

FIG. 2shows a surface state102at the boundary104of the first photonic crystal structure200, where the first photonic crystal structure200includes a 1D photonic crystal comprising layers of a first material202and a second material204fabricated on a substrate206. Examples of 1D photonic crystals are given in Yablonovitch and in Y. Fink, J. N. Winn, S. Fan, C. Chen, J. Michel, J. D. Joannopoulos, and E. L. Thomas, “A DIELECTRIC OMNIDIRECTIONAL REFLECTOR”, Science, Nov. 27, 1998, Volume 282, pages 1679-1682, which is incorporated herein by reference.

Although the first photonic crystal structure200is shown having alternating layers of a first material202and a second material204, where the layers have substantially equal thicknesses, the layer thicknesses and materials202,204may be chosen according to the design of the first photonic crystal structure200, and the layer thicknesses may vary. For example, the design of the first photonic crystal structure200may be such that the layer thicknesses are configured to vary, the layer thicknesses may vary slightly due to fabrication imperfections, the structure may include a top layer having a thickness inconsistent with the periodicity of the remainder of the first photonic crystal structure200, and/or there may be other reasons for variations in the layer thicknesses. Although the first photonic crystal structure200is shown having two different materials202,204, it may have more than two types of materials. Further, although the first photonic crystal structure200is shown having seven layers inFIG. 2, it may have a different number of layers. The first photonic crystal structure200inFIG. 2is shown as a 1D photonic crystal for exemplary purposes, but in other embodiments the first photonic crystal structure200may be a 2D or 3D photonic crystal structure, and may have variations analogous to those described for a 1D photonic crystal structure.

Although the surface states102previously described include plasmons, dielectric surface states, and magnetic surface states, those skilled in the art may recognize that these types of surface states as previously described may be labeled by other terms. For example, as described previously, a “plasmon” may be alternately labeled as a “surface plasmon” or “surface plasmon polariton”. Further, those skilled in the art may recognize other types of surface states and/or other configurations for producing those types of surface states listed above.

FIG. 3shows a surface state102at the boundary104between a first medium106and a second medium108, where in this embodiment the second medium108includes a gain medium302(here, quantum dots303). The quantum dots303are excited via a source306of electromagnetic energy, where the source306may be a laser, a lamp, or a different source of electromagnetic energy, and transfer energy to the surface state102.

The embodiment ofFIG. 3further includes an apparatus308configured to convert radiative electromagnetic energy310into the surface state102, where in the embodiment shown inFIG. 3, the radiative electromagnetic energy310is produced by a laser312. InFIG. 3, the apparatus308configured to convert radiative electromagnetic energy310into the surface state102is a grating, however, other embodiments may include a different apparatus (such as a prism, metallic film, or other device or structure) for converting radiative electromagnetic energy310into a surface state102.

An analogous apparatus309is configured to convert the surface state102into radiative electromagnetic energy311, and a detector318is arranged to receive the radiative electromagnetic energy311. A display320is operably connected to the detector318to display information related to the detected radiative electromagnetic energy311.

AlthoughFIG. 3shows radiative electromagnetic energy310converted into a surface state102and a surface state102converted into radiative electromagnetic energy311, in some embodiments it may be desirable to convert one type of surface state into a different type of surface state (for example, a magnetic surface state into a dielectric surface state) by altering the properties of the boundary along which the surface state102propagates. Such a conversion does not require an apparatus308or309and can be achieved by placing the boundaries sufficiently proximate for coupling.

The first and second media106,108may be any of the combinations previously described as supportive of a surface state. For example, where the surface state102is a dielectric surface state, the first medium106may be a photonic crystal or a polar dielectric having a Restrahlen band and the second medium108may be a dielectric with embedded quantum dots. Or, the two media may be reversed: where the second media108is a photonic crystal or a polar dielectric having a Restrahlen band, with embedded quantum dots, and the first medium106is a different dielectric.

These are just a few examples of the different configurations of the embodiment shown inFIG. 3. Generally, the media106,108can be any of the combinations previously described with respect toFIG. 1, or any combination that supports a surface state, and the quantum dots may be embedded in either or both media106,108.

Although the gain medium302shown inFIG. 3includes quantum dots303, in other embodiments the gain medium302may include one or more different materials. Such gain media and mechanisms for pumping the gain media may be similar to those used in conventional lasers. In some embodiments the gain medium may be a gas, which may include: a mixture of helium and neon, such as in a HeNe laser; carbon dioxide (CO2), such as in a CO2laser; a mixture of argon and krypton such as in an ion laser; and/or a different type and/or mixture of gas. In other embodiments, the gain medium may include a crystal and/or a glass, such as: neodymium-doped yttrium aluminum garnet such as in a Nd:YAG laser; titanium-doped sapphire such as in a Ti:sapphire laser; or a different type of crystal or glass. These are just a few examples of the many kinds of gain media, and one skilled in the art may apply a different gain media than previously described according to the particular application.

The gain medium may be pumped electrically or electromagnetically (where electromagnetic pumping is shown inFIG. 3), depending on the type of medium. For example, where the gain medium includes a gas, the medium may be electrically pumped. Where the gain medium includes a crystal and/or a glass, the medium may be electromagnetically pumped. Pumping of gain media is known to those skilled in the art, and the pumping mechanism for a particular embodiment may be determined by the gain medium and its configuration. Further, those of skill in the art recognize that other names, such as “optical pumping” may be used for “electromagnetic pumping”.

The spatial distribution of the gain medium302may be selected according to a specific embodiment. For example, in some embodiments the gain medium302may be placed in substantially regular intervals along the path of a surface state102to amplify the surface state102regularly as it propagates. In some embodiments the quantum dots303may be close-packed, and in other embodiments the quantum dots303may be spaced apart by a random or regular spacing. There are many ways in which the gain medium may be configured and one skilled in the art may arrange the gain medium302according to a particular embodiment.

Further, althoughFIG. 3shows just one source306of electromagnetic energy incident on the gain medium302, other embodiments may include more than one source306of electromagnetic energy. Further, although the source306is shown as a laser in the embodiment ofFIG. 3, in other embodiments the source306may be, for example, a lamp extending along part or all of the length of the gain medium302.

The embodiment shown inFIG. 3further shows first and second power supplies314,316operably connected to the sources312,306of electromagnetic energy. Power may be supplied to one or more sources such as the sources312,306via one or more power supplies314,316, where in some embodiments a single power supply may power all of the sources312,306, in other embodiments each source312,306may be powered separately, or there may be a different permutation according to the particular embodiment. In other embodiments the power supplies314,316may be operably connected to provide power to a different combination of components of the system, for example, more components or less components or simply a different combination of components. A power supply such as314,316may be employed to provide power to any number of electronic instruments and/or circuitry that may be implemented in a system such as the system shown inFIG. 3.

Circuitry322is operably connected to each of the sources306,312, each of the power supplies314,316, the detector318, and the display320. The circuitry may be configured to determine one or more outputs of the sources306,312(for example, amplitude, frequency, or a different property of the electromagnetic energy output). The circuitry may further be configured to receive information from the detector318, and may send information to the display320. These are just a few examples of how the circuitry322may be employed with the system300shown inFIG. 3. For example, in some embodiments the circuitry322and the display320may be housed in the same component. The detector318is shown inFIG. 3as being arranged to detect the radiative electromagnetic energy311, however in other embodiments the system may include a different number or combination of detectors318, which may be configured to detect electromagnetic energy or a different type of signal, depending on the embodiment. Further, several of the components of the system300are shown as being substantially separate from one another, however in some embodiments some or all of these components may be co-located, such as being in the same housing. There are many different ways that the system ofFIG. 3may be configured and one skilled in the art may tailor the number, type, and configuration of the components according to a particular embodiment. Further, although many of the components shown inFIG. 3are not shown in the embodiments shown and described in the remaining Figures, these components (such as a power supply, detector, circuitry, and/or display) may be incorporated into the embodiments shown and described in the remaining Figures.

FIG. 4shows an embodiment similar to that ofFIG. 3. However, inFIG. 4the gain medium302is a gas (for example, a mixture of helium and neon as in a He—Ne laser) that is electrically pumped via the applied voltage402. Further, to illustrate how the distribution of the gain medium302may vary, the gain medium302inFIG. 4is separated into two different sections, such that a surface state102propagating along the boundary104will first be amplified by the first gain section404, and then will be amplified by the second gain section406.

The embodiment ofFIG. 4, as in the embodiment ofFIG. 3, includes an apparatus308configured to convert radiative electromagnetic energy into the surface state102, where again the radiative electromagnetic energy310is produced by a source312of electromagnetic energy.

Also as inFIG. 3, the first and second media106,108may be any of the combinations previously described as supportive of a surface state when one of the media (106or108) is a gas.

FIG. 5shows a surface state102at a boundary104having a second boundary502that is substantially parallel to the boundary104. The first and second media106,108are, as previously described with respect toFIG. 1, configured to support a surface state. Further, the third medium504that forms a boundary with the first medium106is selected such that the second boundary502supports a surface state. The third medium504may be the same or different from the second medium108. In some embodiments the thickness506of the first medium106may be sufficiently small such that the surface states on each of the boundaries104,502couple to form a single propagating state102as shown inFIG. 5.

InFIG. 5, the third medium504is the same as the second medium108, and the surface state102is a symmetric mode. However, in other embodiments the third medium504may be different from the second medium108.

Although the surface state102is shown for clarity as one surface state, depending on the thickness506and type of medium of the first medium106, there may be a surface state on each of the boundaries104,502, where the two surface states may couple as shown inFIG. 5to form one surface state, the surface states may not couple, and/or there may be minimal coupling of the two surface states, depending on the particular configuration.

In the embodiment ofFIG. 5, quantum dots303are shown symbolically as the gain medium, and are shown as being included in the second medium108. However, as described previously with respect toFIGS. 3 and 4, the gain medium may be included in any of the first, second, and/or third media106,108,504, and/or may be any of the gain media as previously described.

One particular embodiment of the structure shown inFIG. 5is the metal-insulator-metal (MIM) structure, where the second and third media108,504are metal and where the first medium106is a dielectric. In particular, this arrangement is supportive of a transverse electric (TE) surface state mode. MIM structures are described in J. A. Dionne et al., “PLASMON SLOT WAVEGUIDES: TOWARDS CHIP-SCALE PROPAGATION WITH SUBWAVELENGTH-SCALE LOCALIZATION”, Physical Review B, 5 Jan. 2006, Volume 73, pages 035407-1—035407-9, which is incorporated herein by reference.

FIG. 6shows an embodiment having a first layer602including a first medium106, a second layer604including a gain medium302(where the gain medium and its distribution may take a variety of different forms according to a particular embodiment, as previously described), and a third layer606at least partially interposed between the first layer602and the second layer604. The embodiment further includes a third layer606interposed between the first layer602and the second layer604and including a third medium608different from the first medium106and the gain medium302, wherein the first layer602and the third layer606form a first boundary104supportive of a first propagating surface state102, and wherein the gain medium302is configured to evanescently couple to the first propagating surface state102.

The embodiment shown inFIG. 6may also include a fourth layer including a fourth medium (not shown) interposed between the third layer606and the second layer604, wherein the fourth layer and the third layer606form a second boundary (also not shown) supportive of the first propagating surface state102. Such a configuration may produce a surface state102having a distribution like that shown inFIG. 5.

Although not specifically shown inFIG. 6, this embodiment, along with the other embodiments shown inFIGS. 1-10may include other aspects shown in other figures, such as the source306of electromagnetic energy shown inFIG. 3(where the gain medium302is electromagnetically pumped), the applied voltage402(where the gain medium302is electrically pumped), the apparatus308configured to convert radiative electromagnetic energy into a surface state (and/or from a surface state into radiative electromagnetic energy), and/or a different aspect of the other embodiments.

Further, the layers602,604,606are shown as being irregularly-shaped for illustrative purposes, and the specific shape of the layers602,604,606may depend on the particular application.

Further, although three layers602,604,606are shown inFIG. 6, other embodiments may include more than three layers. For example, some embodiments may include a fourth layer, which may be located under the first layer602or in a different location. The fourth layer may include a second gain medium, not shown, which may couple evanescently to the first propagating surface state102. In this case, the second gain medium may be different from, or the same as, the first gain medium302.

Although the third layer606and the third medium608are shown inFIG. 6as having a volume defined by sides, in some embodiments the third layer606may simply be a gap between the first layer602and the second layer604, and in such case the third medium608may simply be air or a different gas, vacuum, or another ambient medium. In this embodiment the coupling between the gain medium302and the surface state102may be varied by varying the separation between the first layer602and the second layer604, where the separation may be varied piezo-electrically or in another way.

FIG. 7shows an embodiment similar to the embodiment shown inFIG. 6, where the apparatus comprises a first layer602including a first medium106, a third layer606including a third medium608, wherein the first layer602and the third layer606form a first boundary104supportive of a first propagating surface state102. The apparatus further comprises a second layer604spaced apart from the first boundary104and including a first gain medium302configured to evanescently couple to the first propagating surface state102.

FIG. 7shows a cross-section of an apparatus supportive of the first propagating surface state102, such that the first propagating surface state102propagates in a direction into the page (versus the embodiment shown inFIG. 6, where the embodiment is shown with the first propagating surface state102propagating along the page). In the embodiment shown inFIG. 7, the second layer606is shown having a substantially amorphous shape, however in other embodiments the second layer606may have a substantially regular shape. The second layer604couples to the first propagating surface state102evanescently as the first propagating surface state102propagates in a direction into the page.

AlthoughFIGS. 6 and 7have shown two different configurations of the second layer604relative to the first and third layers602,606(FIG. 6shows the second layer604between the first and third layers602,606;FIG. 7shows the second layer604substantially beside the first and third layers602,606), other configurations of the second layer604relative to the first and third layers602,606may be arranged such that the first propagating surface state202may couple evanescently to the gain medium302in the second layer604. For example, with reference toFIG. 7, the second layer604may not be in intimate contact with the first and third layers602,606, but may be spaced apart. Further, although bothFIGS. 6 and 7are shown as substantially two-dimensional representations for clarity, in some embodiments the configuration of the second layer604may vary in three dimensions relative to the first and third layers602,606.

FIG. 8shows an embodiment where the boundary104is three-dimensional, such that the second medium108partially surrounds the first medium106, and where a surface state is supported where the first medium106meets the second medium108. The surface state102is shown in two places as an example of where a surface state may propagate, however these are for illustrative purposes and the surface state102may propagate at any of the interfaces between the first material106and the second material108shown inFIG. 8. Further, the rectilinear configuration shown inFIG. 8is also for illustrative purposes and there are many different configurations where the boundary between two materials such as the first and second materials106,108is three-dimensional.

As specified with respect toFIG. 6, the embodiment shown inFIG. 8, along with the other embodiments shown inFIGS. 1-10may include other aspects shown in other figures, such as the gain medium302, the source306of electromagnetic energy shown inFIG. 3(where the gain medium302is electromagnetically pumped), the applied voltage402(where the gain medium302is electrically pumped), the apparatus308configured to convert radiative electromagnetic energy into a surface state (and/or from a surface state into radiative electromagnetic energy), and/or a different aspect of the other embodiments.

In one embodiment, depicted in the flow chart ofFIG. 9, a method comprises: (902) propagating a first dielectric surface state; and (904) passing the first dielectric surface state through a first region, the first region being selected to amplify the first dielectric surface state. Passing the first dielectric surface state through a first region, the first region being selected to amplify the first dielectric surface state may include electromagnetically coupling the first dielectric surface state to a first gain medium (such as the gain medium302shown inFIG. 3) selected to amplify the first dielectric surface state.

In some embodiments, the first gain medium may be located at least partially within the first region. The first gain medium may be any of the gain media listed with respect toFIG. 3, including but not limited to a dielectric, a gas, a crystal, a rare earth element, an amorphous material, or a semiconductor.

The method may further comprise optically pumping the first gain medium, where optically pumping the first gain medium may include coupling optical electromagnetic energy to the first gain medium (such as the energy from the source306shown inFIG. 3).

The method may further comprise electrically pumping the first gain medium, where electrically pumping the first gain medium may include applying electrons to the first gain medium, removing electrons from the first gain medium, applying an electric field to the first gain medium, and/or applying an electric potential to the first gain medium. Electrical pumping of a gain medium is shown inFIG. 4and described previously herein.

The method may further comprise converting radiative electromagnetic energy into the first dielectric surface state, such as with the apparatus308shown inFIG. 3. The method may further comprise converting the first dielectric surface state into radiative electromagnetic energy, the apparatus for which was previously described as being analogous to the apparatus308.

The method may further comprise passing the first dielectric surface state through a second region, the second region being selected to amplify the first dielectric surface state. For example, the second region may be the second gain section406as shown inFIG. 4. The second region may be different from the first region, as is shown inFIG. 4, or the second region may be partially overlapping the first region. The first region (such as the first gain section404shown inFIG. 4) may have a first amplification factor and the second region may have a second amplification factor different from the first amplification factor. These amplification factors may be varied, by varying of the coupling of electromagnetic and/or electrical energy (depending on the type of gain medium). Further, varying the amplification factor may include decreasing the amplification factor to provide substantially zero amplification.

In some embodiments the first dielectric surface state may have first and second energy components, wherein the first region is selected to amplify the first energy component differently from the second energy component. For example, the first energy component may correspond to a first mode and the second energy component may correspond to a second mode different from the first mode. Or, the first and second energy components may correspond to different energy ranges.

Propagating a first dielectric surface state may include: propagating the first dielectric surface state along an interface between a first photonic crystal and a second medium different from the first photonic crystal; or propagating the first dielectric surface state along an interface between a first polar dielectric having a Restrahlen band and a second dielectric. The first polar dielectric having a Restrahlen band may include at least one of silicon carbide (SiC), lithium tantalate (LiTaO3), lithium fluoride (LiF), or zinc selenide (ZnSe). Materials supportive of surface states have been described in detail with respect toFIG. 1.

Although the above methods are described with respect to the flow chart ofFIG. 9, these methods may be applicable to the flow charts ofFIGS. 10 and 11, and may also be applicable to the embodiments shown inFIGS. 1-8.

In another embodiment, depicted in the flow chart ofFIG. 10, a method comprises: (1002) evanescently providing gain energy to a propagating surface state at a first boundary region including an interface between first and second media, from a third medium spaced apart from the interface and separate from the first and second media.

An apparatus corresponding to the method may be found in the Figures, especiallyFIG. 6, however in this embodiment the first and second media would be in the first and third layers602,606, and the third medium would be in the second layer604.

The method may further comprise evanescently providing gain energy to the propagating surface state at a second boundary region including an interface between the first and second media, from a fourth medium spaced apart from the interface and separate from the first and second media. The first and second boundary regions may be the same or different, and the fourth medium may be the same or different from the third medium.

In one embodiment the third medium has a first amplification factor and the fourth medium has a second amplification factor different from the first amplification factor.

In one embodiment the third medium that provides gain energy defines a homogeneous region. Such is the case, for example, of a gas, a crystal, a semiconductor, or other continuous media used for gain.

The method may further comprise: providing gain energy to the third medium, where providing gain energy to the third medium may include providing electromagnetic energy to the third medium and/or providing electrical energy to the third medium. Providing electromagnetic energy to a gain medium is shown inFIG. 3, and providing electrical energy to a gain medium is shown inFIG. 4.

Although the above methods are described with respect to the flow chart ofFIG. 10, these methods may be applicable to the flow charts ofFIGS. 9 and 11, and may also be applicable to the embodiments shown inFIGS. 1-8.

In another embodiment, depicted in the flow chart ofFIG. 11, a method comprises: (1102) propagating a first magnetic surface state; and (1104) passing the first magnetic surface state through a first region, the first region being selected to amplify the first magnetic surface state.

In some embodiments, passing the first magnetic surface state through a first region includes electromagnetically coupling the first magnetic surface state to a first gain medium selected to amplify the first magnetic surface state, which may further include evanescently coupling the first magnetic surface state to the first gain medium.

In some embodiments, propagating a first magnetic surface state includes propagating a plasmon having a transverse electric component, where propagating a plasmon having a transverse electric component may include propagating a plasmon on a metal-insulator-metal (MIM) structure, previously described with respect toFIG. 5.

In one embodiment, propagating a first magnetic surface state may include propagating the first magnetic surface state along an interface between a first magnetic metamaterial and a second material different from the first magnetic metamaterial. Magnetic metamaterials have been described herein with respect toFIG. 5.

Although the above methods are described with respect to the flow chart ofFIG. 11, these methods may be applicable to the flow charts ofFIGS. 9 and 10, and may also be applicable to the embodiments shown inFIGS. 1-8.

Those skilled in the art will recognize that at least a portion of the devices and/or processes described herein can be integrated into an image processing system. Those having skill in the art will recognize that a typical image processing system generally includes one or more of a system unit housing, a video display device, memory such as volatile or non-volatile memory, processors such as microprocessors or digital signal processors, computational entities such as operating systems, drivers, applications programs, one or more interaction devices (e.g., a touch pad, a touch screen, an antenna, etc.), control systems including feedback loops and control motors (e.g., feedback for sensing lens position and/or velocity; control motors for moving/distorting lenses to give desired focuses). An image processing system may be implemented utilizing suitable commercially available components, such as those typically found in digital still systems and/or digital motion systems.

Those skilled in the art will recognize that it is common within the art to implement devices and/or processes and/or systems, and thereafter use engineering and/or other practices to integrate such implemented devices and/or processes and/or systems into more comprehensive devices and/or processes and/or systems. That is, at least a portion of the devices and/or processes and/or systems described herein can be integrated into other devices and/or processes and/or systems via a reasonable amount of experimentation. Those having skill in the art will recognize that examples of such other devices and/or processes and/or systems might include—as appropriate to context and application—all or part of devices and/or processes and/or systems of (a) an air conveyance (e.g., an airplane, rocket, helicopter, etc.), (b) a ground conveyance (e.g., a car, truck, locomotive, tank, armored personnel carrier, etc.), (c) a building (e.g., a home, warehouse, office, etc.), (d) an appliance (e.g., a refrigerator, a washing machine, a dryer, etc.), (e) a communications system (e.g., a networked system, a telephone system, a Voice over IP system, etc.), (f) a business entity (e.g., an Internet Service Provider (ISP) entity such as Comcast Cable, Qwest, Southwestern Bell, etc.), or (g) a wired/wireless services entity (e.g., Sprint, Cingular, Nextel, etc.), etc.

In certain cases, use of a system or method may occur in a territory even if components are located outside the territory. For example, in a distributed computing context, use of a distributed computing system may occur in a territory even though parts of the system may be located outside of the territory (e.g., relay, server, processor, signal-bearing medium, transmitting computer, receiving computer, etc. located outside the territory).

A sale of a system or method may likewise occur in a territory even if components of the system or method are located and/or used outside the territory.

Further, implementation of at least part of a system for performing a method in one territory does not preclude use of the system in another territory.