One-dimensional nanoparticle chain plasmonic laser microcavity

Abstract

The disclosure provides a one-dimensional nanoparticle chain plasmonic laser microcavity, comprising: a metal substrate made of a single crystal metal; a plurality of dielectric blocks arranged on the surface of the metal substrate, the plurality of dielectric blocks have the same height and are arranged in a straight line to form a nanoparticle chain structure; and the gain is improved by changing the arrangement parameters of the plurality of dielectric blocks.

Description

Technical Field

[0001] This disclosure relates to the fields of laser, micro / nano systems, and photonic crystal technology, and in particular to a microcavity for a one-dimensional nanoparticle chain plasmon laser. Background Technology

[0002] Lasers have been developing rapidly since their inception. Currently, miniaturization and integration are the development trends of lasers. However, in the process of laser miniaturization, traditional photonic mode lasers are limited by the diffraction limit, making it difficult to further shrink at the nanoscale and unable to meet the development requirements of future large-scale photonic integration technology. Therefore, surface plasmon lasers have been developed as a method to overcome the diffraction limit problem.

[0003] Surface plasmon lasers have been realized in various structures. Among them, semiconductor-metal nanowire structures have attracted attention due to their simple structure and the advantage of facilitating electric pumping. In nanowire lasers, the semiconductor nanowires serve as both the gain medium and the necessary resonant cavity. The operation involves optical pumping to generate excitons in the gain medium, which then transfer energy to plasmons, causing oscillations and amplification within the nanowire microcavity. This type of laser confines surface plasmons to a nanoscale metal surface, thereby significantly compressing the spatial distribution of the electromagnetic field and creating a nanoscale coherent light source with ultrafast dynamics far exceeding the diffraction limit.

[0004] However, the lack of an insulating dielectric layer in semiconductor-metal nanowire structures leads to high losses, leaving room for further performance improvement in lasers. To enhance laser performance, the microcavity structure needs to be modified to reduce radiation losses and increase the Q-factor. Furthermore, traditional semiconductor lasers suffer from drawbacks such as high threshold voltage, large divergence angle, low quantum conversion efficiency, and poor monochromaticity. Summary of the Invention

[0005] To address the aforementioned problems, this disclosure provides a one-dimensional nanoparticle chain plasmonic laser microcavity to alleviate the technical issues described above in the prior art.

[0006] (I) Technical Solution

[0007] This disclosure provides a microcavity for a one-dimensional nanoparticle chain plasmonic laser, comprising: a metal substrate made of single-crystal metal; a plurality of dielectric blocks disposed on the surface of the metal substrate, wherein the plurality of dielectric blocks have the same height and are arranged in a straight line to form a nanoparticle chain structure; and the gain is improved by changing the setting parameters of the plurality of dielectric blocks.

[0008] According to an embodiment of this disclosure, the average surface roughness of the metal substrate is not higher than 0.8 nm.

[0009] According to an embodiment of this disclosure, the medium block is elliptical cylindrical in shape.

[0010] According to embodiments of this disclosure, the setting parameters of the media block include the length of the media block, the width of the media block, the height of the media block, the number of media blocks, and the spacing between adjacent media blocks.

[0011] According to embodiments of this disclosure, the nanoparticle chain structure includes a central gradient portion and edge periodic portions on both sides of the central gradient portion.

[0012] According to embodiments of this disclosure, the dielectric blocks in the nanoparticle chain structure are symmetrically distributed, and the spacing between adjacent dielectric blocks in the middle gradient portion gradually increases from the center to both sides, while the width of the dielectric blocks gradually increases from the center to both sides.

[0013] According to embodiments of this disclosure, the dielectric blocks in the edge periodic portion are identical and have equal spacing.

[0014] According to embodiments of this disclosure, the spacing between adjacent dielectric blocks ranges from 160nm to 280nm.

[0015] According to embodiments of this disclosure, the height of the elliptical cylindrical dielectric block ranges from 100nm to 200nm, and the length of the dielectric block ranges from 120nm to 200nm, in order to achieve single-mode transmission in nanowires under visible and infrared wavelengths; the width of the dielectric block ranges from 60nm to 150nm.

[0016] According to embodiments of this disclosure, the material for preparing the metal substrate is selected from gold, silver, copper, aluminum, and nickel, and the material for preparing the dielectric blocks is selected from hybrid organic-inorganic perovskite materials. The number of dielectric blocks ranges from 15 to 23.

[0017] (II) Beneficial Effects

[0018] As can be seen from the above technical solution, the one-dimensional nanoparticle chain plasmonic laser microcavity disclosed herein has at least one or a portion of the following beneficial effects:

[0019] (1) It can overcome the limitations of the diffraction limit and better realize the miniaturization of lasers;

[0020] (2) It can effectively improve the quality factor of the microcavity, and the Q value is 2 to 3 times higher than that of ordinary periodic uniform dielectric block microcavities;

[0021] (3) It can control specific light and effectively realize the mode selection function;

[0022] (4) It has a simple structure and is easy to implement micro-nano fabrication experimental processes;

[0023] (5) It is beneficial for the application of plasmonic lasers in semiconductor integration processes and has better ultrafast dynamic characteristics. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the three-dimensional structure of the microcavity of a one-dimensional nanoparticle chain plasmon laser according to an embodiment of this disclosure.

[0025] Figure 2 This is a frontal view of the microcavity structure of a one-dimensional nanoparticle chain plasmon laser according to an embodiment of this disclosure.

[0026] Figure 3 This is a side-view structural diagram of the microcavity of a one-dimensional nanoparticle chain plasmon laser according to an embodiment of this disclosure.

[0027] Figure 4 This is a top-view structural diagram of the microcavity of a one-dimensional nanoparticle chain plasmon laser according to an embodiment of this disclosure.

[0028] Figure 5 The diagram shows the Q-values ​​of the one-dimensional nanoparticle chain plasmonic laser microcavity structure at different frequencies according to embodiments of this disclosure.

[0029] Figure 6 The electric field distribution of the microcavity of the one-dimensional nanoparticle chain plasmon laser according to an embodiment of this disclosure is shown at a characteristic frequency of 430 THz.

[0030] Figure 7a This is a schematic diagram showing the energy bands of a surface plasmon laser microcavity with different widths according to an embodiment of this disclosure.

[0031] Figure 7b This is a schematic diagram showing the energy bands of a surface plasmon laser microcavity at different intervals according to an embodiment of this disclosure.

[0032] Figure 8 This is a comparison diagram of the Q values ​​of a surface plasmonic laser microcavity and a conventional periodic uniform laser microcavity structure according to embodiments of this disclosure.

[0033] [Explanation of key component symbols in the accompanying drawings of this disclosure embodiment]

[0034] 1-Metal substrate; 2-Dielectric block; 3-Optical pump excitation source. Detailed Implementation

[0035] This disclosure provides a microcavity structure for a one-dimensional nanoparticle chain plasmonic laser, characterized by: a metal substrate and a nanoparticle chain structure composed of elliptical cylindrical dielectric blocks of different sizes; the elliptical cylindrical dielectric blocks are placed on the surface of the metal substrate; the elliptical cylindrical dielectric blocks have the same height and their center points are located on a straight line; the nanoparticle chain composed of the elliptical cylindrical dielectric blocks is symmetrical from left to right; the gain is maximized and the loss is reduced by optimizing the size, spacing and number of the dielectric blocks.

[0036] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0037] In this embodiment of the disclosure, a one-dimensional nanoparticle chain plasmonic laser microcavity is provided, combined with Figures 1 to 4 As shown, the one-dimensional nanoparticle chain plasmonic laser microcavity includes:

[0038] Metal substrate 1 is made of single-crystal metal;

[0039] Multiple dielectric blocks 2 are disposed on the surface of the metal substrate. The multiple dielectric blocks have the same height and are arranged in a straight line to form a nanoparticle chain structure.

[0040] The gain can be increased by changing the setting parameters of the multiple media blocks.

[0041] The settings parameters for the media blocks include the length, width, height, number, and spacing between adjacent media blocks.

[0042] The metal substrate has a single-crystal metal crystal, a smooth surface, and a low average roughness of 0.8 nm.

[0043] According to embodiments of this disclosure, the material for preparing the metal substrate 1 is selected from gold, silver, copper, aluminum, and nickel. If a metal exists that can further reduce metal loss without affecting the generation of surface plasmons, it can also be used.

[0044] According to an embodiment of this disclosure, the nanoparticle chain structure is composed of a row of elliptical cylindrical media blocks of the same height but different sizes arranged in a straight line.

[0045] According to embodiments of this disclosure, the nanoparticle chain structure composed of elliptical cylindrical dielectric blocks comprises two parts: a central gradient part and an edge periodic part.

[0046] According to embodiments of this disclosure, in conjunction with Figures 1 to 4As shown, the elliptical cylindrical dielectric blocks have different sizes. Specifically, the height of the elliptical cylindrical dielectric blocks is the same, the length of the dielectric blocks (i.e., the length of the major axis of the elliptical cross section of the elliptical cylindrical dielectric block) is the same, the width of the dielectric blocks in the middle gradient part (i.e., the length of the minor axis of the elliptical cross section of the elliptical cylindrical dielectric block) W1 gradually widens from the center of the nanoparticle chain structure to both sides, and the width W2 of the dielectric blocks in the edge periodic part is the same.

[0047] According to the embodiments of this disclosure, the spacing between adjacent elliptical cylindrical dielectric blocks is different. Specifically, the spacing D1 between adjacent dielectric blocks in the middle gradient part gradually increases from the center of the nanoparticle chain structure to both sides, while the spacing D2 between adjacent dielectric blocks in the edge part is the same.

[0048] According to embodiments of this disclosure, the material used to prepare the elliptical cylindrical dielectric block is selected from hybrid organic-inorganic perovskite materials, namely lead halide perovskite.

[0049] According to an embodiment of this disclosure, the dimensions of the elliptical cylindrical dielectric block are specifically: the height is within the range of [100nm, 200nm], and the length is within the range of [120nm, 200nm], so as to realize single-mode transmission in nanowires under visible and infrared wavelengths. The width W of the dielectric block varies in the range of [60nm, 150nm].

[0050] According to embodiments of this disclosure, the spacing D between adjacent elliptical cylindrical dielectric blocks varies within the range of [160 nm, 280 nm] to ensure that an appropriate mode is selected.

[0051] According to embodiments of this disclosure, the number of elliptical cylindrical media blocks in the nanoparticle chain structure is between 15 and 23.

[0052] According to embodiments of this disclosure, the microcavity of the one-dimensional nanoparticle chain plasmonic laser operates in the visible and infrared bands. The space above and below the microcavity of the one-dimensional nanoparticle chain plasmonic laser is air.

[0053] According to embodiments of this disclosure, in conjunction with Figures 1 to 4 As shown, elliptical cylindrical nanodielectric blocks 2 are arranged in a straight line on a metal substrate 1, resembling a one-dimensional photonic crystal. Based on the variations in their size and spacing, they can be roughly divided into two parts: a gradient section in the middle and a periodic section at the two edges. As can be seen from the figure, in the gradient section, the width of the elliptical cylindrical dielectric blocks gradually increases from the center to both sides, and the spacing between adjacent dielectric blocks also gradually increases from the center to both sides. Therefore, the width of the elliptical cylindrical dielectric blocks 2 should satisfy W2 > W1, and the spacing should be D2 > D1. In the periodic edge section, the width and spacing of the dielectric blocks remain unchanged, uniformly arranged on the metal substrate. Its structure is similar to a periodic photonic crystal. Therefore, the periodic edge section can be regarded as a periodic Bragg mirror, enhancing the reflectivity at both ends, thereby reducing losses to a certain extent.

[0054] The nanoparticle chain structure composed of elliptical cylindrical dielectric blocks 2 can be approximated as a one-dimensional photonic crystal waveguide microcavity structure. The material of dielectric block 2 has a gain effect, which can effectively gain light waves that meet the resonance condition. Specific wavelength light waves are confined within the microcavity and continuously resonate; therefore, the microcavity structure of this invention has excellent mode selection capabilities. Simultaneously, to avoid insufficient gain leading to resonance failure, the width W1 of the middle portion of the elliptical cylindrical dielectric block 2 should be appropriately chosen and should not be too small.

[0055] like Figure 1 As shown, the laser microcavity and the optical pump excitation source 3 constitute a laser. The excitation light can be the pump light, and the laser microcavity generates laser light based on the excitation light.

[0056] Reference Figure 5 , Figure 6 , Figure 7a , Figure 7b ,as well as Figure 8 As shown, Figure 5 The figure shows the Q values ​​of the microcavity structure proposed in this invention at different frequencies. The data clearly demonstrates that this microcavity structure has excellent mode selection capabilities; the Q value is highest for light frequencies that meet the resonance condition, thus effectively enabling the selection of light waves at specific frequencies. The highest Q value in the figure is 263, corresponding to a characteristic frequency of 430 THz. Figure 6 The electric field distribution of the microcavity structure proposed in this invention at a frequency of 430 THz is shown. The characteristic frequency corresponding to the electric field mode in the figure is the light wave frequency that satisfies the resonance condition. It can be found that the photon energy is mainly confined in the intermediate medium region. The laser output of this structure is mainly concentrated on both sides of the nanoparticle chain. Figure 7a and Figure 7b The diagram shows the band structure of the microcavity structure proposed in this invention with different widths and spacings. It can be seen that when the width W of the elliptical cylindrical dielectric block becomes narrower or the spacing D between the dielectric blocks becomes smaller, the cutoff frequency of the band structure becomes higher. In other words, by optimizing the width and spacing of the dielectric blocks, the photon energy of a specific frequency can be concentrated in the middle position between the narrow width and the small spacing, thereby reducing losses and improving the Q value. Figure 8 The figure shows the Q values ​​corresponding to different structures. As can be seen from the figure, the microcavity structure proposed in this invention can indeed effectively improve the Q value, which is 2 to 3 times higher than that of ordinary periodic uniform dielectric block microcavities.

[0057] Example 1

[0058] In this embodiment, the laser operates in the wavelength range of 700nm-800nm.

[0059] In this embodiment, the metal substrate 1 is made of single-crystal silver because silver has lower metal loss compared to other common metals in the 700nm-800nm ​​wavelength range. The dimensions of the metal substrate are set to 5000nm*2000nm*750nm.

[0060] In this embodiment, the elliptical cylindrical dielectric block material is CH3NH3PbI3 perovskite material, which has a high exciton binding energy and can provide a large gain. During implementation, the refractive index of the perovskite material at 750 nm is 2.243. The nanoparticle chains are exposed to air, where the refractive index is 1. The nanoparticle chain structure composed of multiple dielectric blocks directly contacts the metal substrate 1, generating surface plasmons. Simultaneously, the high refractive index difference effectively confines the electromagnetic waves to the semiconductor-metal interface, such as... Figure 6 As shown.

[0061] In this embodiment, the elliptical cylindrical dielectric block is set to a height of 150 nm and a length of 150 nm to ensure that only the ground-state transverse mode exists in the surface plasmon waveguide mode at wavelengths of 700 nm-800 nm. Regarding the width of the dielectric block, in the intermediate gradient section, the width W1 at the very center is set to 100 nm, and increases by 16 nm for each outward expansion, up to 148 nm; in the edge periodic section, the width W2 remains constant at 148 nm. Regarding the spacing between dielectric blocks, in the intermediate gradient section, the distance D1 between the center dielectric block and adjacent dielectric blocks is set to 250 nm, and increases by 10 nm for each outward expansion, up to 280 nm; in the edge periodic section, the distance D2 between adjacent dielectric blocks remains constant at 280 nm. The number of dielectric blocks is odd, such as... Figure 6 As shown, there are 15 blocks.

[0062] In this embodiment, the nanoparticle chain structure composed of elliptical cylindrical dielectric blocks is similar to a one-dimensional photonic crystal microcavity structure, which can resonate electromagnetic waves of a specific frequency and filter out electromagnetic waves of irrelevant frequencies, thereby achieving mode selection. Furthermore, due to the non-uniform arrangement of the dielectric blocks, the cutoff frequency at the photonic bandgap varies with the width and spacing of the dielectric blocks. In this embodiment, the middle part of the nanoparticle chain structure is designed with a narrow width and small spacing, resulting in a higher bandgap cutoff frequency in the middle part, thereby effectively reducing losses and improving the Q value. Figure 8 As can be seen, the Q value is 2 to 3 times higher than that of ordinary periodic uniform dielectric block microcavity.

[0063] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various elements and methods described above are not limited to the specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0064] Based on the above description, those skilled in the art should have a clear understanding of the microcavity structure of the one-dimensional nanoparticle chain plasmonic laser disclosed herein.

[0065] In summary, this disclosure provides a one-dimensional nanoparticle chain plasmonic laser microcavity structure. This surface plasmonic laser microcavity, leveraging the plasmon effect, achieves the basic functions of a plasmonic laser while maintaining both physical and mode dimensions smaller than half a wavelength. By optimizing the width and spacing of the dielectric blocks in the nanoparticle chain structure, mode selection for suitable electromagnetic waves is achieved. Simultaneously, the cutoff frequency of the corresponding bandgap in the middle section is increased to reduce losses and improve the Q-value. This microcavity structure offers advantages such as miniaturization, high quality factor, and better frequency selectivity. Its fabrication process is compatible with CMOS technology, facilitating fabrication and integration, and enabling large-scale production with reduced costs. These comprehensive performance characteristics pave the way for further laser research and have broad application prospects.

[0066] It should also be noted that the above are different embodiments provided by this disclosure. These embodiments are used to illustrate the technical content of this disclosure and are not intended to limit the scope of protection of this disclosure. A feature of one embodiment can be applied to other embodiments through suitable modifications, substitutions, combinations, or separations.

[0067] It should be noted that, unless otherwise specified herein, having "a" element is not limited to having a single element, but may include one or more of the element.

[0068] Furthermore, unless otherwise specified, the ordinal numbers such as "first," "second," etc., used herein are merely for distinguishing multiple elements with the same name and do not indicate any hierarchy, order of execution, or process sequence among them. A "first" element and a "second" element may appear together in the same component or separately in different components. The presence of an element with a higher ordinal number does not necessarily indicate the presence of another element with a lower ordinal number.

[0069] In this article, unless otherwise specified, the so-called characteristic A "or" ( oThe term "r" or "and / or" for feature B means that A exists alone, B exists alone, or A and B exist simultaneously; the term "and" or "and" or "and" for feature A means that A and B exist simultaneously; the terms "including", "containing", "having", and "containing" refer to, but are not limited to, these.

[0070] Furthermore, in this document, terms such as "up," "down," "left," "right," "front," "back," or "between" are used only to describe the relative positions of multiple elements and can be extended to include translation, rotation, or mirroring. Additionally, unless otherwise specified, the statement "one element is on another element" or similar statements do not necessarily indicate that the element is in contact with the other element.

[0071] Furthermore, unless specifically described or required to occur in a specific order, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. Moreover, the above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments.

[0072] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A microcavity for a one-dimensional nanoparticle chain plasmonic laser, comprising: The metal substrate is made of single-crystal metal. Multiple dielectric blocks are disposed on the surface of the metal substrate. The multiple dielectric blocks have the same height and are arranged in a straight line to form a nanoparticle chain structure. The nanoparticle chain structure includes a middle gradient portion and edge periodic portions on both sides of the middle gradient portion. The gain can be increased by changing the setting parameters of the multiple media blocks; In the nanoparticle chain structure, the dielectric blocks are symmetrically distributed. In the middle gradient section, the spacing between adjacent dielectric blocks gradually increases from the center to both sides, and the width of the dielectric blocks gradually increases from the center to both sides.

2. In the one-dimensional nanoparticle chain plasmonic laser microcavity according to claim 1, the average surface roughness of the metal substrate is not higher than 0.8 nm.

3. The microcavity of the one-dimensional nanoparticle chain plasmon laser according to claim 1, wherein the dielectric block is elliptical cylindrical in shape.

4. In the microcavity of the one-dimensional nanoparticle chain plasmonic laser according to claim 3, the setting parameters of the dielectric block include the length of the dielectric block, the width of the dielectric block, the height of the dielectric block, the number of dielectric blocks, and the spacing between adjacent dielectric blocks.

5. In the microcavity of the one-dimensional nanoparticle chain plasmon laser according to claim 1, the dielectric blocks in the edge periodic portion are identical and the spacing is set equally.

6. In the microcavity of the one-dimensional nanoparticle chain plasmonic laser according to claim 4, the spacing between adjacent dielectric blocks ranges from 160 nm to 280 nm.

7. In the microcavity of the one-dimensional nanoparticle chain plasmonic laser according to claim 4, the height of the elliptical cylindrical dielectric block ranges from 100nm to 200nm, and the length of the dielectric block ranges from 120nm to 200nm, so as to realize single-mode transmission in nanowires under visible and infrared wavelengths; the width of the dielectric block ranges from 60nm to 150nm.

8. The microcavity of the one-dimensional nanoparticle chain plasmonic laser according to claim 1, wherein the metal substrate is made of gold, silver, copper, aluminum, or nickel, the dielectric block is made of a hybrid organic-inorganic perovskite material, and the number of dielectric blocks ranges from 15 to 23.

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