Tuning emission wavelength of quantum emitters by phase change materials

Abstract

A device having a layered structure including a layer of phase change material and a layer of host material having embedded quantum emitters is tuned. An electric field is applied through the layer of host material and the layer of phase change material to change an emission wavelength of the quantum emitters. A phase of the phase change material is changed in each of one or more local regions of the phase change material in a non-volatile manner to form a local change opposite a corresponding one of the quantum emitters in the layer of host material to locally change the electric field at the corresponding quantum emitter.

Description

[0001] Contract reference

[0002] The project that led to this application has already received funding from Switzerland (QuantERA project "RouTe", funded by the Swiss National Science Foundation under authorization agreement 20QT21_175389). Background Technology

[0003] This disclosure relates to tuning the emission wavelength of a quantum transmitter, and more specifically to phase change materials for locally modifying the electric field at the quantum transmitter.

[0004] Several quantum information processing concepts involve single-photon emitters (e.g., quantum emitters, such as molecules and quantum dots) and can be based on: (i) coupling the on-chip emission of a single quantum emitter to an optical cavity mode; or (ii) coupling individual quantum emitters to each other. Summary of the Invention

[0005] According to embodiments, a method, apparatus, and device are disclosed.

[0006] According to a first aspect, this disclosure is embodied as a method for tuning the emission wavelength of a quantum emitter. The method relies on a device having a layered structure (e.g., a bilayer structure). The layered structure includes a phase change material layer and a matrix material layer, wherein one or more quantum emitters are embedded in the matrix material layer. An electric field is then applied through the matrix material layer and the phase change material layer to change the emission wavelength of the quantum emitter, for example, due to the Stark effect and other related effects. Finally, the phase of the phase change material (PCM) is changed in a non-volatile manner in each of one or more local regions of the PCM, for example, from an amorphous state to a crystalline state. That is, the phase of the PCM in the local region preferably changes from a substantially amorphous structure to a substantially crystalline structure, such that the remaining portion of the PCM has a substantially amorphous structure.

[0007] These localized regions create localized phase changes that are relative to (e.g., face-to-face) the corresponding quantum emitters in the matrix material layer. This results in a localized alteration of the electric field at the corresponding quantum emitter. Consequently, the emission wavelength of the quantum emitter can be tuned individually, for example, in a programmable manner, by controllably altering the phase in selected regions of the PCM layer.

[0008] Due to the change in the static dielectric constant following the phase transition (e.g., once a crystalline phase is reached), the electric field at the emitter location changes. This allows for alteration of the local electric field intensity experienced by each emitter, and thus the intensity of the Stark effect. This, in turn, allows for individual tuning of the emission wavelength of each quantum emitter. The degree of tuning depends on the geometry of the local regions (of the phase transition) and the extent of the phase change, such as the amount of crystallinity of the PCM in these regions.

[0009] Therefore, the above method can be advantageously used in quantum information processing applications, and more generally in applications requiring coupling (i) individual quantum emitters to each other, (ii) individual quantum emitters to a given light wavelength (e.g., to a remote quantum emitter) or (iii) a given quantum emitter to electromagnetic emission of one or more optical cavity modes including a layered cavity, as in the embodiments.

[0010] Preferably, the one or more local regions are first regions that cause a first local phase change, and the method further includes reconstructing the PCM layer by: (i) changing the phase of each of the one or more second local regions of the PCM back to the amorphous structure before (ii) changing the phase of each of the one or more second local regions of the PCM from an amorphous structure to a crystalline structure. Like the first regions, the second local regions cause a second local phase change, which is relative to the corresponding quantum emitter in the matrix material layer. However, they can differ in size and number. This again results in a localized change of the electric field at the corresponding quantum emitter, although to a different degree than before.

[0011] In a preferred embodiment, the PCM is configured such that, after changing the phase of the PCM in each of one or more local regions, the average static relative permittivity of the local region is at least 1.5 times greater than the average static relative permittivity of the remaining portion of the PCM layer.

[0012] Preferably, the phase of the PCM is altered in each of these local regions using a radiating element that can be controllably moved relative to the PCM layer. The radiating element includes one of a laser device and a heated nanoscale probe tip.

[0013] In a preferred embodiment, the electric field is applied parallel to the matrix material layer. In variations, it is applied transversely to the layered structure.

[0014] According to another aspect, this disclosure is embodied as an apparatus including a transmitting device, circuitry, and a radiating device. The transmitting device includes two electrodes and a layered structure. The layered structure includes a PCM layer and a matrix material layer with an embedded quantum emitter. The matrix material layer extends over the PCM layer. It further extends between the two electrodes, for example, in a vertical or horizontal (e.g., lateral) configuration. The circuitry is connected to the two electrodes and configured to generate, in operation, an electric field through the matrix material layer and the phase-change material layer via the two electrodes to change the emission wavelength of the quantum emitter. The radiating device is configured to controllably change the phase of the PCM in a non-volatile manner in each of one or more local regions of the PCM. Consistent with the first aspect of this disclosure, the local regions are opposite (e.g., face-to-face) to corresponding quantum emitters in the matrix material layer. In operation, changing the phase of the PCM in these regions results in a localized change in the electric field at the corresponding quantum emitter.

[0015] In one embodiment, the radiation device includes a radiation element, which is one of a laser device and a heatable nanoscale probe tip. The device is configured to controllably move the radiation element relative to the layered structure, so that the phase of the PCM in a local region can be easily changed.

[0016] For example, the device can be configured to scan the layered structure with a radiating element, for example, by laterally moving the layered structure and / or the radiating element. Note that the distance characterizing the lateral accuracy (in the sense of resolution) is preferably smaller than the average lateral spacing between the quantum emitters. The lateral spacing is measured along a direction parallel to the average plane of the layered structure.

[0017] According to the last aspect, this disclosure is embodied as a transmitting device. The device includes a layered structure having a PCM layer and a matrix material layer in which one or more quantum emitters are embedded. The matrix material layer extends over the PCM layer. Furthermore, the device includes two electrodes disposed on each side of the matrix material layer. In operation, the electrodes allow an electric field to be generated through the matrix material layer and the phase-change material layer to change the emission wavelength of the quantum emitters. Consistent with other aspects of this disclosure, the PCM also includes one or more local regions opposite to the respective quantum emitters in the matrix material layer. The local regions have a phase different from the phase of the remainder of the PCM layer. Therefore, in operation of the device, the local regions locally change the electric field at the respective quantum emitters.

[0018] The emitting device typically includes a substrate on which the PCM layer extends. For example, the PCM layer is located between the substrate and a matrix material layer. As described above with respect to previous aspects of this disclosure, the electrodes may have a vertical or horizontal (e.g., lateral) configuration. For example, in a horizontal configuration, the electrodes may be patterned directly on the substrate so that a layered structure extends between the electrodes.

[0019] Preferably, the PCM comprises GeSbTe or HfO2. Furthermore, the matrix material layer may, for example, comprise crystalline or polymeric materials, while the quantum emitter may comprise epitaxially grown semiconductor quantum dots, colloidal quantum dots, or organic emitters comprising dyes and other emitters (such as oligomers). Other material combinations may be considered.

[0020] In a preferred embodiment, the average static relative permittivity of the local region is at least twice that of the average static relative permittivity of the remaining region.

[0021] In this embodiment, the average distance between quantum emitters in the matrix material layer is greater than or equal to 50 nm. Furthermore, the average in-plane dimension of the local region is preferably between 50 nm and 5000 nm. All in-plane dimensions are measured along a direction parallel to the average plane of the matrix material layer (or the layered structure). Simultaneously, the average thickness of the local region is preferably greater than or equal to 1 nm; this thickness is measured perpendicular to the matrix material layer from the interface between the matrix material layer and the PCM layer.

[0022] The average thickness of the PCM layer is preferably between 50 nm and 200 nm, while the average thickness of the matrix material layer is preferably between 20 nm and 200 nm. Similarly, this thickness is measured perpendicular to the respective layer.

[0023] The above overview is not intended to describe every illustrated embodiment or implementation of this disclosure. Attached Figure Description

[0024] The accompanying drawings included in this application are incorporated in and form a part of this specification. They illustrate embodiments of this disclosure and, together with the description, serve to explain the principles of this disclosure. The drawings illustrate only certain embodiments and do not limit the scope of this disclosure.

[0025] Figure 1 A depicts a two-dimensional cross-sectional view of a launching device according to some embodiments of the present disclosure.

[0026] Figure 1 B depicts a two-dimensional top view of a launching device according to some embodiments of the present disclosure.

[0027] Figure 2A Selected components of an apparatus according to some embodiments of the present disclosure are depicted.

[0028] Figure 2B Selected components of an apparatus according to some embodiments of the present disclosure are depicted.

[0029] Figure 3 A flowchart illustrating a method for tuning the emission wavelength of a quantum transmitter according to some embodiments of the present disclosure is shown.

[0030] While the invention may be adapted to various modifications and alternatives, its details have been shown by way of example in the accompanying drawings and will be described in detail. However, it should be understood that the invention is not limited to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Detailed Implementation

[0031] This disclosure relates to aspects of tuning the emission wavelength of quantum emitters; more specifically, it relates to a phase-change material to locally modify the electric field at these quantum emitters. While this disclosure is not necessarily limited to such applications, various aspects of this disclosure can be understood through the discussion of different examples using this context.

[0032] Several quantum information processing concepts involve single-photon emitters (e.g., quantum emitters, such as molecules and quantum dots) and can be based on: (i) coupling the on-chip emission of a single quantum emitter to an optical cavity mode; or (ii) coupling individual quantum emitters to each other.

[0033] Quantum transmitters can each rely on resonance with cavity mode or other quantum transmitters. Most quantum transmitters can have slightly different emission wavelengths, which leads to a broadening of the overall emission spectrum due to inhomogeneity. To achieve the desired coupling, the narrow emission spectra of these individual quantum transmitters may need to overlap with the emission spectra of other quantum transmitters or cavity mode spectra.

[0034] Several techniques are known for attempting to tune the emission wavelength of quantum transmitters, including, for example, strain tuning and electric field tuning. However, such techniques cannot be used to individually tune multiple individual transmitters to overcome the adverse effects of non-uniform broadening.

[0035] refer to Figure 1-3 First, we describe an aspect of this disclosure that relates to a method for tuning the emission wavelength of a quantum transmitter 16.

[0036] Figure 2A and 2B Selected components of the device according to an embodiment may be shown. These devices each include, for example... Figure 1 The transmitting device 1 and radiating elements 37 and 38 are shown in A and B, respectively. In each embodiment, the transmitting device 1 can be moved laterally relative to the radiating elements 37 / 38 to locally change the phase of one or more layers.

[0037] Method implementation can significantly lead to, for example Figure 1 The transmitting devices 1 are shown in Figures A and B. These methods can be notably used respectively, such as... Figure 2A and 2B The devices 101 and / or 102 shown are used for implementation. Figure 2A In the middle, the radiating elements 37 / 38 can be heated nanoscale probe tips, while... Figure 2B In this context, radiating elements 37 / 38 can be laser devices. This method and its variations are collectively referred to as "this method". All reference numerals Sn refer to... Figure 3 The flowchart describes the method steps, while the numerical reference numerals involve... Figure 1 And the physical components or assemblies of apparatus 1 and devices 101 and 102 shown in Figure 2. Apparatus 1 and devices 101 and 102 relate to other aspects of this disclosure, which will be described in detail later.

[0038] Figure 2A and 2B The method can depend on the transmitting device, for example, as in Figure 3 The flowchart is provided at step S10. The transmitting device 1 may have layered structures 12, 15, which include a phase change material (PCM) layer 12 and a matrix material layer 15. The layered structures 12, 15 may simply be a two-layer structure, as assumed in the figures. However, the layered structures 12, 15 may include an additional intermediate layer between the PCM layer 12 and the matrix material layer 15. This intermediate layer may be, for example, an adhesive layer or a protective layer. However, the intermediate layer may be very thin, for example, less than 10 nm thick, to maintain the desired properties of structures 12, 15, as explained below.

[0039] The matrix material layer 15 may have one or more embedded quantum emitters 16. For example, it may involve at least one quantum emitter 16, although the matrix material 15 may include multiple (more than one) quantum emitters 16, as in... Figure 1 As shown in A and B, the quantum emitter 16 (also called a single-photon source) facilitates the emission of one photon at a time, unlike classical light. Several types of active nanomaterials are known that can be engineered into the single quantum emitter 16, and spontaneous emission can be tunable by altering the local density of optical states in the dielectric nanostructure. The quantum emitter can be, for example, a single atom, ion, molecule, or defect center. In this document, the quantum emitter may include solid-state emitters such as quantum dots, color centers, organic emitters, and carbon nanotubes. In some embodiments, the quantum emitter may be an epitaxially grown semiconductor quantum dot, colloidal quantum dot, or organic emitter, such as an organic dye, as discussed later with reference to another aspect of this disclosure.

[0040] In step S20, an electric field is applied through the matrix material layer 15 and the PCM layer 12. The applied electric field can be constant, such as static, and is typically constant. Due to the Stark effect or other related effects, the applied field can cause a change in the emission wavelength of the quantum emitter 16.

[0041] Due to circuit 32 (see Figure 2A and2B ), can be transmitted via two electrodes 10 (see Figure 1 An electric field is applied to A and B. Figure 1 In examples A and B, the emitting device 1 may include an optical and electrically passive substrate. In some embodiments, the substrate may not emit light and may be electrically insulating. Electrodes 10 of conductive material may be patterned directly on the substrate 11. Thus, a voltage can be applied locally via the electrodes 10. The applied voltage may be in the range of 1-100V.

[0042] Furthermore, in step S30, the phase of the PCM12 can be changed in each of one or more local regions 14 of the PCM (e.g., in a non-volatile manner). These regions form local phase changes (e.g., local patterns) that are opposite to corresponding quantum emitters in the quantum emitters 16 in the matrix material layer 15. Local phase changes may be caused by a single local region 14 (e.g., Figure 1 (As assumed in A and B) or formed by two or more such local regions. Local regions can also have a variety of possible shapes. For example, a local change can be formed by a single local region with an approximately cylindrical shape (such as...). Figure 1 (As assumed in A and B). However, local alterations can also be formed by two or more local regions with phase changes. Furthermore, each local region can have a specific shape. For example, local alterations can be achieved due to two (possibly separate) regions with a bow shape. Structures such as these can be sought to maximize the dielectric enhancement effect relative to a simple cylindrical (or somehow circular) structure 14. More generally, the geometry and number of local regions can be optimized to shape and / or adjust the intensity of the electric field.

[0043] In all cases, region 14 forms a local phase change, which is associated with the quantum emitter. That is, the local phase change surrounds or includes the orthogonal projection of emitter 16 in PCM layer 12, such as Figure 1 As assumed in A and B. In the example of a bow change (not shown) formed by laterally opposite regions with altered phases, the electric field hotspot is located between two local regions (which have in-plane triangular shapes). Therefore, in this case, the orthogonal projection of the emitter is ideally located between the two opposite bow regions.

[0044] Note that reference numeral 1 in the figure can indicate a transmitting device obtained after the phase of the selected region 14 of the PCM layer 12 has been partially changed.

[0045] like Figure 1As shown in A and B, changing the phase of the PCM in these regions 14 results in a localized change in the electric field at the corresponding quantum emitter 16. The applied electric field is depicted as dashed line 20. For example, in these instances, the electric field is schematically visualized using a set of lines (such as line 20) whose direction at each point is the same as the direction of the electric field. Due to the phase change in the PCM region 14, the field near the quantum emitter is altered.

[0046] The field alteration allows the emission wavelength of the quantum emitter to be tuned individually in a programmatic manner. For example, the size and crystallization state of local region 14 can be changed as needed to achieve a desired emission wavelength. Note that the emission spectrum of the quantum emitter can be monitored in real time (e.g., during programming of PCM layer 12 (S30)) to adequately tune the emission wavelength. In some embodiments, the programming step S30 is combined with a spectral measurement step to gradually tune the emission wavelength (e.g., stepwise). In some embodiments, a related procedure is applied to directly form region 14 of a known size (S30), for example, by applying a given amount of radiation (heat or light) for a predetermined duration.

[0047] Preferably, radiating elements 37 and 38 (such as heated nanoscale probe tips 37) are used. Figure 2A ) or laser device 38 ( Figure 2B (S30) PCM region 14 is obtained. Radiation elements 37, 38 can locally change the phase of the PCM in a non-volatile manner (e.g., from amorphous to crystalline). This is equivalent to "programming" PCM layer 12. The change is "non-volatile" meaning that the phase transition remains stable even after radiation (light or heat) is interrupted. Device 1 can be reprogrammed as needed to operate layered structures 12, 15, as discussed later with reference to some embodiments. Therefore, the PCM can be selected such that these phase transition regions 14 are stable but not necessarily irreversible.

[0048] Note that step S30 can be performed after step S20. In some embodiments, an electric field (step S20) can be applied after the phase of the PCM in local region 14 has been changed (step S30).

[0049] Due to the change in dielectric constant obtained from the phase transition (e.g., once a crystalline phase is reached), a change in the electric field at the emitter 16 location may occur. This allows for alteration of the local electric field intensity experienced by each emitter 16, and thus the intensity of the Stark effect. This ability to alter allows for the individual tuning of the emission wavelength of each quantum emitter 16. The degree of tuning can be related to the geometry of the local region 14 (of the phase transition) and the extent of the phase change, such as the amount of crystallinity of the PCM in these regions.

[0050] See now Figure 1 Phases A and B of PCM 12 and 14 can be changed (S30) from an amorphous or substantially amorphous structure to a crystalline or substantially crystalline structure in local region 14, as described above. As a result, the remaining portion 12 of the PCM can include an amorphous structure.

[0051] A sufficient difference in the static relative permittivity between the two phases of PCM 12 can be sought; the relative permittivity of a material with respect to zero frequency is referred to as its static relative permittivity. Specifically, the PCM can be advantageously chosen such that, after the phases of PCM 12, 14 in each local region 14 of S30 have been changed, the static relative permittivity of local region 14 is at least 1.5 times (or at least twice) larger than the static relative permittivity of the remaining portion 12. Note that, in this document, the static relative permittivity can be an effective (or average) permittivity. The static permittivity between the two phases of PCM 12, 14 can differ by a factor of at least 1.5 (if not 2) to cause a sufficient change in the electric field density. However, in practice, this factor may be slightly less than 2 while still providing satisfactory results.

[0052] For example, PCMs (such as Ge2Sb2Te5) can result in a static dielectric constant of about 16 in the amorphous phase, compared to about 30 in the tetragonal phase. Such materials allow for a sufficient variation in electric field density at a ratio of approximately 1.875. In some embodiments, properties can be obtained by using HfO2, which results in a static dielectric constant of approximately 25 for the amorphous phase relative to approximately 125 for the tetragonal phase, corresponding to a ratio of approximately 5.

[0053] This method can be used in applications requiring electromagnetic emission that involves coupling (i) individual quantum emitters to each other, (ii) individual quantum emitters to light of a given wavelength (e.g., a remote quantum emitter), or (iii) one of the quantum emitters to a layered optical cavity mode, such as... Figure 3 The flowchart shows step S40.

[0054] PCM may be reprogrammed, for example, as Figure 3As shown. That is, after the PCM has been locally modified to obtain a first local region 14 with a changed phase, the PCM layer 12 can be reconstructed by returning some or all of the phase changes in the first regions 14 (S60) to their amorphous structure. For example, the initial state of the PCM is restored before changing the PCM phase in each of one or more second local regions 14 from an amorphous state to a crystalline state (S20). Similar to the first local change caused by the first local region, the second local change caused by the second local region 14 is associated with the corresponding quantum emitter 16 in the layer 15. This can also locally change the electric field at the quantum emitter 16. That is, due to the crystalline regions in these second local regions, these second changes are typically formed relative to the quantum emitter 16, wherein these second changes may partially surround or include orthogonal projections of these quantum emitters in the PCM layer. The second regions may be substantially similar to the first regions, although larger (or smaller) and thicker (or thinner). Furthermore, reprogramming may involve different regions. For example, compared to a previous programming cycle, the PCM can be reprogrammed to change the phase in more (or fewer) numbers of second regions 14, or in completely different regions (forming local changes relative to different quantum emitters). If necessary, the electric field can be turned off (step S50) before the phase change (S60) of the local region 14 is returned to the initial (amorphous) phase.

[0055] Now for more specific reference Figure 2A and 2B The phase of PCMs 12 and 14 can be altered (S30) using radiating elements 37 and 38 that are controllably movable relative to PCM layer 12. Notably, the radiating elements may include heated nanoscale probe tips 37 or laser devices 38. That is, the phase of the PCM can be altered by locally applying energy in the form of light or heat to each of one or more local regions 14, for example, through the matrix material layer 15 (or substrate 11).

[0056] exist Figure 2B In this example, a phase change is possible due to the laser beam generated by laser device 38. In this example, the laser beam strikes the PCM layer 12 from the top through the matrix layer 15. In a variant, the PCM layer 12 can be constructed by applying a laser beam from below (e.g., through a fully transmissive substrate 11). Figure 2AIn the example, a localized region 14 is obtained due to the heating of the nanoscale probe tip 37. Similar to the laser device 38, the probes 33, 37 can be independently controlled and actuated within the device 101. Several probe tips may be used simultaneously. However, embodiments relying on a single probe tip 37 can be considered, for example, when forming a relatively small number of regions 14 (typically about 100 or less) and / or when regions 14 can have small volumes. The time required for precise, localized operation can be about one second or less. The probes 33, 37 may be heated via a heating element (not shown) in thermal contact with the probe tip or by applying an electrical signal to the probe 33 to heat the probe by Joule heating. Typically, techniques derived from scanning tunneling microscopy (STM) and atomic force microscopy (AFM) can be used.

[0057] Another aspect of this disclosure may relate to devices 101, 102 that can be used to implement the method according to this disclosure. Referring now to... Figure 2A and 2B Two examples of this device are described.

[0058] These devices 101 and 102 may include a transmitting device 1, a circuit 32, and a radiating device. Furthermore, devices 101 and 102 may include various controllers 34 and 35 and circuits, as well as a mobile station.

[0059] The emitting device 1 may include two electrodes 10 and layered structures 12, 15. The electrodes 10 may be formed on a chip. The layered structure may include a PCM layer 12 and a matrix material layer 15 extending above the PCM layer 12. The quantum emitter 16 may be embedded in the matrix material layer. Note that the matrix material layer 15 extends above the PCM layer 12, which may indicate that it is on top of or below the PCM layer 12, depending on the chosen orientation.

[0060] Layer 15 may further extend between the two electrodes 10, for example, in a vertical or horizontal (lateral) configuration. That is, the electrodes may be arranged on each side (top and bottom) relative to the lateral direction of the layered structure. Because layers 12 and 15 are preferably in direct contact with each other (thus forming a double-layered structure), the electrodes may be arranged vertically or horizontally to sandwich the two layers 12, 15 in the middle. Figure 1 The transmitting device 1 shown in A and B depicts an example horizontal configuration.

[0061] Circuit 32 can be connected to two electrodes 10. Circuit 32 is configured to generate an electric field through the matrix material layer 15 and the PCM layer 12 via the two electrodes 10. In operation, the electric field can cause a change in the emission wavelength of the quantum emitter 16, as previously explained.

[0062] The radiating device can be configured to controllably change the phase of the PCM in a non-volatile manner within a selected local region 14. As previously explained, such a region 14 can be formed opposite to a corresponding quantum emitter 16 in the matrix material layer 15 to locally change the electric field at the corresponding quantum emitter 16 during operation. This can be achieved, for example, using radiating elements 37, 38. In some embodiments, the radiating element can be a laser device 38. In other embodiments, the radiating element can be a heatable nanoscale probe tip 37, for example, the tip 37 can be mounted on a cantilever 33 ( Figure 2A On the other hand, as is commonly associated with SPL technology. In both cases, devices 101, 102 can be configured to controllably move radiating elements 37, 38 relative to the layered structures 12, 15. That is, the layered structures 12, 15 and the radiating elements 37, 38 can be controllably moved relative to each other in order to obtain a phase-changing selection region 14.

[0063] In some embodiments, devices 101, 102 may be configured to scan radiating elements 37, 38 relative to the layered structures 12, 15. Note that the distance characterizing lateral accuracy (in a resolution sense) may be smaller than (or substantially smaller than) the average lateral spacing between the quantum emitters 16. This may be along a direction parallel to the average plane of the layered structure, for example, with respect to... Figure 1 - The lateral spacing distance is measured in a direction parallel to the plane (x, y) in the example of Figure 2. For example, devices 101, 102 may include a holder 31, and the transmitting device 1 may be mounted on the holder 31. The holder itself may be mounted on the xy stage 31, or form part of it, for example, in Figure 2A , Figure 2B The xy stage 31 can be connected to the control system 35. In addition, another controller 34 can be connected to both the control system 35 and the radiating elements 37 and 38 to vertically move the radiating elements 37 and 38 to the optimal vertical position above the layered structures 12 and 15.

[0064] refer to Figure 1 Regarding A and B, we will now discuss another aspect relating to the transmitting device 1. As previously described, device 1 may include a layered structure, such as PCM layers 12, 14, and a matrix material layer 15 in which a quantum emitter 16 is embedded, wherein the matrix material layer 15 may extend over the PCM layers 12, 14. Furthermore, device 1 may include two electrodes 10 arranged vertically or horizontally (e.g., laterally) on each side of the layered structure.

[0065] In operation, electrode 10 allows an electric field to be generated through matrix material layer 15 to alter the emission wavelength of quantum emitter 16. Furthermore, and as a result of programming PCM layers 12, 14, the emitting device 1 may include one or more local regions 14 opposite to the corresponding quantum emitters in quantum emitters 16 within matrix material layer 15. The phase of local regions 14 may differ from the phase of the remainder of PCM layer 12, and may cause a local modification of the electric field at the corresponding emitter 16 during operation.

[0066] Note that various possible geometries for electrode 10 are envisioned. In some embodiments, electrode 10 may be shaped as opposing parallelepipeds. In some embodiments, electrode 10 may form concentric rings and / or include more than two electrodes. For example, four electrodes on each side of the layered region, through which the field direction can be set in any direction parallel to the plane of the layered structure. In some embodiments, electrode 10 may be formed in an array to subdivide the layered region into smaller sub-regions, for example, to enable localized changes in field orientation. Furthermore, such subdivision can be used to dynamically change the emission wavelength of only a subset of quantum emitters by varying the voltage applied to the individual electrodes 10. In a horizontal configuration, the distance between electrodes 10 can be between 2 and 1000 micrometers. The distance between electrodes 10 can be between 10 and 100 micrometers. The distance between electrodes 10 can achieve a sufficiently high electric field (0.1-1 MV / cm). A more compact structure can be achieved using a vertical configuration of the electrodes.

[0067] As discussed previously, PCMs 12 and 14 can significantly comprise hafnium(IV) oxide (HfO2). In some embodiments, the PCM layer comprises a germanium-antimony-tellurium alloy (denoted as GeSbTe, or simply GST), or more generally, an alloy comprising each of Ge, Sb, and Te, plus additional elements such as Se. The PCM layer may, for example, comprise Ge2Sb2Te5, as previously described. In some embodiments, the PCM layer may comprise Ge2Sb2Se4Te1, which combines broadband transparency (1-18.5 μm) and high optical contrast (Δn = 2.0). As previously mentioned, such materials allow for a factor of approximately 1.5 (or greater) between the effective, static relative permittivity in local region 14 and the remaining portion 12.

[0068] The matrix material layer 15 may be, for example, a crystalline material or a polymeric material. Suitable examples of crystalline materials may include crystalline semiconductors and organic crystals, such as pentacene, dibenzotriphenylene, and tribenzotriphenylene. Suitable examples of polymers may include polystyrene, poly(methyl methacrylate), and styrene-ethylene-butene-styrene.

[0069] Quantum emitter 16 may comprise or be composed of epitaxially grown semiconductor quantum dots, such as InAs / GaP quantum dots or other relevant quantum dots suitable for electric field tuning. In some embodiments, quantum emitter 16 may comprise or be composed of colloidal quantum dots (e.g., II-VI or III-V semiconductors) or perovskites. Emitter 16 may comprise cadmium selenide (CdSe), such as an n-type II-VI semiconductor or a metal halide perovskite (APbX3, where A = Cs, CH3NH3, or (NH2CHNH2)1-x(CH3NH2)x, where 0 ≤ x ≤ 1, and X = Cl, Br, or I). In some embodiments, a single molecule (e.g., an organic dye) may be used. As previously described, other instances of quantum emitters are conceivable.

[0070] The layered structures 12, 14, and 15 can be supported by an optically and electrically passive substrate 11, such as a substrate comprising one or more of Si, GaAs, GaP, InP, oxides (e.g., SiO2 or Al2O3), and glass. The substrate can provide mechanical stability for the device 1. For completeness, the electrical contacts (electrodes) 10 may comprise any suitable electrical conductor, such as gold, silver, aluminum, indium tin oxide (ITO), tungsten, or doped semiconductors.

[0071] In some implementations, such as Figure 1 As shown in Figures A and B, substrate 11 supports layered structures 12, 14, and 15. PCM layers 12 and 14 may be sandwiched between substrate 11 and matrix material layer 15. Electrodes 10 may be patterned on substrate 11 in a lateral configuration. That is, layered structures 12 and 15 extend laterally between electrodes 10. In this case, an electric field is applied parallel to layered structures 12, 14, and 15 (S20). In a variant, a vertical electrode configuration is envisioned, where the electrodes are made of a sufficiently transparent material (such as ITO or doped semiconductor), thereby allowing an electric field to be applied perpendicular to the substrate plane.

[0072] That is, in Figure 1 In the examples A and B, device 1 may include a matrix layer 15 on top of PCM layers 12, 14, which itself is on top of substrate 11. However, in variations, different sequences are contemplated, including a PCM layer on top of a matrix layer, with the matrix layer itself on top of the substrate. Such structures can all have lateral electrode configurations. Furthermore, vertical configurations are contemplated, where, for example, a top electrode layer extends on top of a bilayer structure (matrix-PCM or PCM-matrix) that itself extends on top of the bottom electrode layer and the substrate. In that case, the top electrode may be made of an optically transparent material (e.g., ITO) to allow for laser programming and light extraction from the quantum emitter.

[0073] Quantum emitters 16 may be spaced at least 50 nm (on average) apart in the matrix layer 15, for example in some embodiments where the finite resolution of radiating elements 37, 38 is used to form local regions 14. In some embodiments, quantum emitters 16 may be laterally spaced at least 50 nm (on average). That is, the spacing distance, as measured parallel to the (x, y) plane, may be greater than or equal to 50 nm. This spacing distance can facilitate that quantum emitters 16 can be individually addressed relative to PCM programming (S30) to individually tune their emission wavelengths via electric field tuning. In some embodiments, a smaller spacing distance may be conceivable if a smaller radiative resolution is available.

[0074] The average in-plane size of local region 14 can be larger than the average in-plane size of the quantum emitter, for example, as... Figure 1 As in examples A and B, the local changes are each formed by a single region 14. For example, the local regions may be generally cylindrical in shape. Nevertheless, as discussed previously, these local regions can have any suitable shape and be grouped to form local patterns (e.g., changes), wherein the local patterns surround or include the projection positions of the corresponding quantum emitters. For example, the average in-plane dimension of the local regions 14 can be between 50 nm and 5000 nm. The in-plane dimension is along the average plane parallel to the matrix material layer 15 (or the layered structure) (e.g., parallel to...). Figure 1 The direction of (x, y) in A and B is measured. In some embodiments, region 14 may be formed relative to a single quantum emitter, and the in-plane size of the region may be on the same order of magnitude as the average in-plane spacing between the quantum emitters. However, a single region 14 may overlap with several quantum emitters 16 (and thus tune several emitters at a time).

[0075] In some embodiments, the average thickness (or depth) of the local region 14 can typically be greater than or equal to 1 nm. This thickness is measured perpendicular to the matrix material layer 15, for example, along direction z in the figures. Furthermore, the thickness of the region can be measured from the interface between the matrix material layer 15 and the PCM layer 12, since region 15 is typically formed directly below the interface with the matrix material layer 15.

[0076] It should be noted that the depth of region 14 can be equal to the thickness of PCM layers 12 and 14, such as... Figure 1 As shown in A. The PCM light absorption at the emission wavelength of the quantum emitter can be kept low, for example, by using a material with low absorption at the emitter wavelength and / or a sufficiently thin layer. As a result, the average thickness of the PCM layers 12, 14 can be between 50 nm and 200 nm, and in some embodiments less than 100 nm. Meanwhile, the average thickness of the matrix material layer 15 can be between 20 nm and 200 nm.

[0077] While this disclosure has been described with reference to a limited number of embodiments, variations, and drawings, those skilled in the art will understand that various changes can be made and equivalents can be substituted without departing from the scope of this disclosure. Specifically, features (apparatus-like or method-like) described in a given embodiment, variation, or shown in the drawings may be combined with or substituted for other features in other embodiments, variations, or drawings without departing from the scope of this disclosure. Therefore, various combinations of features described with respect to any of the foregoing embodiments or variations are contemplated, and these combinations remain within the scope of the appended claims. Furthermore, many minor modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from the scope of this disclosure. Therefore, this disclosure is intended to be limited to the specific embodiments disclosed, but rather to include all embodiments falling within the scope of the appended claims. In addition, many other variations besides those explicitly mentioned above are contemplated. For example, other materials besides those explicitly mentioned herein may be contemplated, further device (and electrode) geometries may be used, etc.

[0078] Various embodiments of this disclosure have been described for illustrative purposes, but are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein has been chosen to explain the principles of the embodiments, their practical application, or technical improvements to technologies found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for tuning the emission wavelength of a quantum transmitter, the method comprising: A device with a layered structure is provided, the layered structure comprising a phase change material layer and a matrix material layer, wherein one or more quantum emitters are embedded in the matrix material layer; An electric field is applied through the matrix material layer and the phase change material layer to change the emission wavelength of the quantum emitter; as well as In each of one or more local regions of the phase change material, the phase of the phase change material is changed in a non-volatile manner to obtain a local phase transition relative to the corresponding quantum emitter in the quantum emitter in the matrix material layer, and the electric field is locally modified at the corresponding quantum emitter.

2. The method according to claim 1, wherein, In one or more local regions, the phase of the phase change material changes from a substantially amorphous structure to a substantially crystalline structure, such that the remaining portion of the phase change material has a substantially amorphous structure.

3. The method according to claim 2, in, The one or more local regions are the first regions that cause the first local phase change; and The method further includes reconstructing the layers of the phase change material through the following steps: Before the following steps, the phase of each of the first regions is changed back to the amorphous structure; The phase of each of one or more second local regions of the phase change material is changed from an amorphous structure to a crystalline structure to obtain a second local phase transition relative to the corresponding quantum emitter in the quantum emitter in the matrix material layer, so as to locally change the electric field at the corresponding quantum emitter.

4. The method according to claim 2 or 3, wherein, The phase change material is such that, after the phase of the phase change material in each of the one or more local regions has been changed, the average static relative permittivity of the local region is at least 1.5 times greater than the average static relative permittivity of the remaining portion.

5. The method according to any one of claims 1 to 3, wherein, The phase of the phase change material is altered in each of the one or more local regions using a radiating element that can be controllably moved relative to a layer of the phase change material. The radiating element includes one of a laser device and a heated nanoscale probe tip.

6. The method according to any one of claims 1 to 3, wherein, An electric field is applied and the phase of the phase change material is changed so that the electromagnetic emissions of the individual quantum emitters are coupled to each other.

7. The method according to any one of claims 1 to 3, wherein, The electric field is applied and the phase of the phase change material is changed in order to couple one of the quantum emitters with the electromagnetic emission of an optical cavity mode comprising the cavity of the layered structure.

8. The method according to any one of claims 1 to 3, wherein, The electric field is applied parallel to the matrix material layer.

9. A device including a quantum transmitter, the device comprising: A transmitting device comprising two electrodes and a layered structure, the layered structure comprising a phase change material layer and a matrix material layer embedded with one or more quantum emitters, wherein the matrix material layer is above the phase change material layer and extends between the two electrodes; A circuit, connected to the two electrodes and configured to generate an electric field through the two electrodes during operation, passing through the matrix material layer and the phase change material layer, to change the emission wavelength of the quantum emitter; as well as A radiation device is configured to, during operation, controllably change the phase of the phase change material in a non-volatile manner in each of one or more local regions of the phase change material to obtain a local phase change relative to a corresponding quantum emitter in the quantum emitter in the matrix material layer, thereby locally modifying the electric field at the corresponding quantum emitter.

10. The device according to claim 9, wherein, The radiation device includes a radiation element, which is one of a laser device and a heatable nanoscale probe tip, and The device is configured to controllably move the radiating element relative to the layered structure.

11. The device according to claim 10, wherein, The device is further configured to scan the hierarchical structure using the radiating element, wherein the distance characterizing lateral precision is less than the average lateral spacing distance between the quantum emitters, wherein the lateral spacing distance is measured along a direction parallel to the average plane of the hierarchical structure.

12. A launching device, comprising: A layered structure comprising a phase change material layer and a matrix material layer embedded with one or more quantum emitters, wherein the matrix material layer extends over the phase change material layer; as well as Two electrodes are arranged on each side of the layered structure to allow an electric field to be generated through the matrix material layer and the phase change material layer during operation, thereby changing the emission wavelength of the quantum emitter. The phase change material includes one or more local regions having a phase different from that of the remainder of the phase change material, thereby creating a local phase change in operation relative to a corresponding quantum emitter in the quantum emitter in the matrix material layer, so as to locally modify the electric field at the corresponding quantum emitter.

13. The launching device according to claim 12, wherein, The phase change material includes one of GeSbTe and HfO2.

14. The launching device according to claim 12 or 13, wherein, The matrix material layer includes one of a crystalline material and a polymer material; and The quantum emitter includes one of epitaxially grown semiconductor quantum dots, colloidal quantum dots, and organic emitters.

15. The launching device according to claim 12 or 13, wherein, The average distance between the quantum emitters in the matrix material layer is greater than or equal to 50 nm.

16. The launching device according to claim 12 or 13, wherein, The average in-plane dimension of the local region is between 50 and 5000 nm, and the average in-plane dimension is measured along a direction parallel to the average plane of the matrix material layer.

17. The launching device according to claim 12 or 13, wherein, The average thickness of the local region is greater than or equal to 1 nm, and the thickness is perpendicular to the matrix material layer and measured from the interface between the matrix material layer and the phase change material layer.

18. The launching device according to claim 12 or 13, wherein, The average thickness of the phase change material layer is between 50 nm and 200 nm, and the average thickness of the matrix material layer is between 20 nm and 200 nm.

19. The launching device according to claim 12 or 13, wherein, The average static relative permittivity of the local region is at least twice that of the average static relative permittivity of the remaining region.

20. The launching device according to claim 12 or 13, wherein, The launching device further includes: A substrate, wherein the phase change material layer extends on the substrate such that the phase change material layer is between the substrate and the matrix material layer, and The electrodes are patterned on the substrate so that the layered structure extends between the electrodes.

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