Surface plasmon polariton laser and its preparation method and application

Abstract

A surface plasmon polariton laser and its preparation method and application, the preparation method comprising: spin coating a silver nanowire dispersion on a substrate to obtain device one; heating device one for a period of time under an inert atmosphere to obtain device two; preparing an aluminum oxide film on device two; spin coating a dye dispersion on the aluminum oxide film and then annealing to obtain the surface plasmon polariton laser. The device structure designed by the present invention can realize a coherent light source with a scale property that breaks through the optical diffraction limit, and can reduce the size of the laser device to a scale below half the wavelength of the emitted laser, laying a foundation for the application of integrated photonic devices.

Description

Technical Field

[0001] The invention belongs to the field of nano-optical devices, and in particular relates to a surface plasmon polariton laser and a preparation method and application thereof. Background Art

[0002] Surface plasmon lasers have attracted extensive attention from researchers because of their properties such as breaking through the optical diffraction limit and ultrafast time response, and they can be used as coherent light source devices in integrated photonic chips in the future. However, semiconductor nanowires or semiconductor nanosheets are commonly used as the resonant structure of the laser in surface plasmon polariton laser devices. Metal film materials provide plasmon excitation, and metal film can be regarded as a two-dimensional material. Electrons on the metal surface can oscillate freely in two dimensions on it, so it has high propagation scattering loss, which makes the threshold of plasmon lasers based on metal film materials generally high, further hindering its application. In addition, the growth of semiconductor nanowires and nanosheet materials cannot achieve uniform size and controllable spatial position, so semiconductor nanomaterials cannot be used as array structures, and on-chip integration cannot be achieved, blocking its development path as a photonic integrated chip.

[0003] The gain materials in traditional surface plasmon polariton lasers are mostly inorganic semiconductor materials, because the excitation of surface plasmon polaritons is the result of the coupling of excitons in semiconductors and free electrons on the metal surface. However, the binding energy of excitons in inorganic semiconductor materials is generally low, and a large number of excitons cannot be generated at room temperature. Only under high-power pumping can a large number of excitons be generated to couple with electrons, resulting in a high threshold of surface plasmon polariton lasers using inorganic semiconductor materials for gain, which hinders their application. Summary of the invention

[0004] In view of this, one of the main objectives of the present invention is to provide a surface plasmon polariton laser and a preparation method and application thereof, in order to at least partially solve at least one of the above-mentioned technical problems.

[0005] In order to achieve the above object, as one aspect of the present invention, a method for preparing a surface plasmon polariton laser is provided, comprising:

[0006] S1: spin coating the silver nanowire dispersion on the substrate to obtain device 1;

[0007] S2: heating device 1 for a period of time under an inert atmosphere to obtain device 2;

[0008] S3: preparing an aluminum oxide film on device 2;

[0009] S4: spin coating the dye dispersion on the aluminum oxide film and then annealing to obtain the surface plasmon polariton laser.

[0010] As another aspect of the present invention, a surface plasmon polariton laser obtained by the preparation method as described above is also provided.

[0011] As another aspect of the present invention, there is also provided application of the surface plasmon polariton laser as described above in the field of nano-optical devices.

[0012] Based on the above technical solutions, it can be seen that the surface plasmon polariton laser and its preparation method and application of the present invention have at least one or part of the following advantages over the prior art:

[0013] 1. The present invention provides a new plasmon laser device structure, which is very different from the existing plasmon laser device structure and provides a new direction for the development of plasmon laser devices;

[0014] 2. The device structure designed by the present invention can realize a coherent light source with the property of breaking through the optical diffraction limit scale, and can reduce the size of the laser device to a scale below half the wavelength of the emitted laser, laying a foundation for the application of integrated photonic devices;

[0015] 3. The device designed by the present invention has an array structure. Different from the existing discrete plasmon laser devices, the structure designed by the present invention can constitute an array laser device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To further illustrate the specific technical content of the present invention, the following is a detailed description with reference to specific examples and accompanying drawings, wherein:

[0017] Figure 1 This is a flow chart for preparing a surface plasmon polariton laser based on silver nanowires / R6G dye molecules in an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of the structure of a surface plasmon polariton laser based on silver nanowires / R6G dye molecules in an embodiment of the present invention.

[0019] Description of reference numerals:

[0020] 1-Silicon dioxide single crystal substrate; 2-Silver nanowire layer; 3-Aluminum oxide film; 4-R6G dye molecule@PVA film. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0022] The present invention mainly aims at the problems of high threshold, inability to prepare arrays, and small application prospects in the existing surface plasmon polariton lasers, and designs a new surface plasmon polariton laser structure based on organic dye molecule gain and silver nanowires. The present invention uses silver nanowires as a new laser structure of the resonant cavity of the plasmon laser. Specifically, the preparation method of the new surface plasmon polariton laser structure based on silver nanowires / R6G dye molecules includes uniformly spin-coating a certain concentration of silver nanowire dispersion on a silicon dioxide single crystal substrate; using atomic layer deposition technology to conformally deposit a layer of aluminum oxide film on the above substrate; preparing R6G dye molecules into a water dispersion according to a certain ratio; preparing PVA into a water dispersion according to a certain mass fraction; fusing R6G water dispersion and PVA water dispersion according to a certain ratio; uniformly spin-coating the above mixed solution on the above prepared substrate, and preparing the new surface plasmon polariton laser structure based on silver nanowires / R6G dye molecules through an annealing process at 50 degrees Celsius for 30 minutes.

[0023] The present invention discloses a method for preparing a surface plasmon polariton laser, comprising:

[0024] S1: spin coating the silver nanowire dispersion on the substrate to obtain device 1;

[0025] S2: heating device 1 for a period of time under an inert atmosphere to obtain device 2;

[0026] S3: preparing an aluminum oxide film on device 2;

[0027] S4: spin coating the dye dispersion on the aluminum oxide film and then annealing to obtain the surface plasmon polariton laser.

[0028] In some embodiments of the present invention, the concentration of silver nanowires in the silver nanowire dispersion in step S1 is 1 to 2 mg / mL, for example, 1 mg / mL, 1.2 mg / mL, 1.5 mg / mL, 1.8 mg / mL, or 2 mg / mL.

[0029] In some embodiments of the present invention, the diameter of the silver nanowires in the silver nanowire dispersion in step S1 is 80 to 120 nanometers, for example, 80 nanometers, 90 nanometers, 100 nanometers, 110 nanometers, and 120 nanometers; the length is 8 to 12 micrometers, for example, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, and 12 micrometers.

[0030] In some embodiments of the present invention, the spin coating time in step S1 is 20 to 40 seconds, for example, 20 seconds, 30 seconds, or 40 seconds; the spin coating speed is 2000 to 4000 rpm, for example, 2000 rpm, 3000 rpm, or 4000 rpm.

[0031] In some embodiments of the present invention, the substrate in step S1 is a silicon dioxide single crystal substrate;

[0032] In some embodiments of the present invention, the silicon dioxide single crystal substrate is pre-treated;

[0033] In some embodiments of the present invention, the pretreatment includes at least one of cleaning, drying and ultraviolet ozone treatment.

[0034] In some embodiments of the present invention, the heating time in step S2 is 4 to 6 minutes, for example, 4 minutes, 5 minutes, 6 minutes; the heating temperature is 45 to 55 degrees Celsius, for example, 45 degrees Celsius, 48 ​​degrees Celsius, 50 degrees Celsius, 52 degrees Celsius, 55 degrees Celsius;

[0035] In some embodiments of the present invention, the inert atmosphere in step S2 includes at least one of nitrogen, carbon dioxide, and helium.

[0036] In some embodiments of the present invention, the thickness of the aluminum oxide film in step S3 is 5 to 10 nanometers, for example, 5 nanometers, 6 nanometers, 7 nanometers, 8 nanometers, 9 nanometers, or 10 nanometers.

[0037] In some embodiments of the present invention, the dye dispersion in step S4 is a mixed solution of R6G and PVA, wherein the concentration of R6G is 2 to 8 wt%, for example, 2 wt%, 4 wt%, 6 wt%, 8 wt%; the concentration of PVA is 1 to 4 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%;

[0038] In some embodiments of the present invention, the spin coating time in step S4 is 1500 to 2500 rpm, for example, it can be 1500 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2500 rpm; the spin coating speed is 20 to 40 seconds, for example, it can be 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes.

[0039] In some embodiments of the present invention, the annealing temperature in step S4 is 40 to 60 degrees Celsius, for example, 40 degrees Celsius, 45 degrees Celsius, 50 degrees Celsius, 55 degrees Celsius, and 60 degrees Celsius; the annealing time is 30 to 60 minutes, for example, 30 minutes, 40 minutes, 50 minutes, and 60 minutes.

[0040] The invention also discloses a surface plasmon polariton laser obtained by the preparation method as described above.

[0041] The invention also discloses the application of the surface plasmon polariton laser as described above in the field of nano-optical devices.

[0042] In an exemplary embodiment, the present invention discloses a method for preparing a novel surface plasmon polariton laser, comprising the following steps:

[0043] Step 1: Ultrasonic dispersion of silver nanowires in deionized water; wherein the silver nanowires have a diameter of 80-120 nanometers and a length of 8-12 micrometers.

[0044] Step 2: The silicon dioxide single crystal substrate is cleaned by ultrasonic cleaning of acetone, isopropanol, ethanol, and deionized water for 15-25 minutes in sequence;

[0045] Step 3: Blowing the cleaned silicon dioxide single crystal substrate dry under high-purity nitrogen;

[0046] Step 4: treating the dried silicon dioxide single crystal substrate in an ultraviolet ozone environment for 10-20 minutes;

[0047] Step 5: Spin-coat the silver nanowire dispersion prepared in step 1 onto the silicon dioxide single crystal substrate processed in step 4; wherein, during the spin-coating process, the spin-coating speed is 2000-4000 revolutions per minute, and the time is 20-40 seconds.

[0048] Step 6: heating the substrate coated with silver nanowires in a nitrogen environment at 45-55 degrees Celsius for 4-6 minutes;

[0049] Step 7: placing the heated substrate into the chamber of the atomic layer deposition system, and conformally depositing a layer of aluminum oxide film with a thickness of 5-10 nanometers thereon;

[0050] Step 8: Ultrasonic dispersion of R6G (rhodamine 6G) dye molecules in deionized water according to a certain mass fraction to obtain a R6G dye dispersion;

[0051] Step 9: Ultrasonic dispersion of PVA in deionized water according to a certain mass fraction to obtain a PVA solution;

[0052] Step 10: Fully mix the R6G dye molecule aqueous dispersion and the PVA (polyvinyl alcohol) aqueous dispersion, wherein the concentration of R6G in the mixed solution is 2-8wt%, and the concentration of PVA is 1-4wt%;

[0053] Step 11: Spin-coat the mixed solution onto the substrate on which the aluminum oxide film is deposited; wherein the spin-coating process has a rotation speed of 1500-2500 revolutions per minute and a time of 20-40 seconds.

[0054] Step 12: Anneal the substrate at 40-60 degrees Celsius for 30-60 minutes in an atmospheric environment, and after cooling, a novel surface plasmon polariton laser structure of silver nanowires / R6G dye molecules can be prepared.

[0055] The technical solution of the present invention is further described below by means of specific embodiments in combination with the accompanying drawings. It should be noted that the following specific embodiments are only used as examples, and the protection scope of the present invention is not limited thereto.

[0056] The chemicals and raw materials used in the following examples are either commercially available or homemade by known preparation methods.

[0057] Example 1

[0058] See also Figure 1-2 As shown, the preparation of the novel surface plasmon polariton laser structure based on silver nanowires / R6G dye molecules in this embodiment is carried out in the following specific steps:

[0059] Step 1: ultrasonically disperse the silver nanowires in deionized water to form a dispersion with a silver nanowire concentration of 2 mg / mL, the silver nanowires having a diameter of 100 nanometers and a length of 10 micrometers, an ultrasonic power of 20 watts, and a time of 5 minutes;

[0060] Step 2: The silicon dioxide single crystal substrate is ultrasonically cleaned in acetone, isopropanol, ethanol, and deionized water in sequence, with an ultrasonic power of 200 watts for 20 minutes;

[0061] Step 3: Blowing the cleaned silicon dioxide single crystal substrate dry under high-purity nitrogen;

[0062] Step 4: treating the dried silicon dioxide single crystal substrate in an ultraviolet ozone environment for 15 minutes;

[0063] Step 5: Spin-coat the silver nanowire dispersion prepared in step 1 onto the silicon dioxide single crystal substrate 1 processed in step 4 at a spin-coating speed of 3000 revolutions per minute for 30 seconds;

[0064] Step 6: heating the substrate coated with the silver nanowires at 50 degrees Celsius for 5 minutes to form a silver nanowire layer 2;

[0065] Step 7: Place the heated substrate into the chamber of the atomic layer deposition system, and conformally deposit a layer of aluminum oxide film 3 on it. Use trimethylaluminum (TMA) as the precursor of aluminum oxide to deposit various double-layer thickness Al2O3 nanolaminated films in a customized fixed ALD (atomic layer deposition) system. In this process, water is used as a co-reactant, and all depositions are completed at 90°C. Before deposition, the sample is kept at 90°C for 30 minutes. The deposition parameters are: precursor pulse / exposure / clear 0.1s / 30s / 40s (TMA) and 2s / 30s / 40s (H2O). The precursor pulse and purge steps are carried out with nitrogen gas flows of 25sccm and 100sccm as carrier gas, respectively;

[0066] Step 8: Ultrasonic dispersion of R6G dye molecules in deionized water at an ultrasonic power of 200 watts for 30 minutes;

[0067] Step 9: PVA was dispersed in deionized water by ultrasonic method, with ultrasonic power of 200 watts and ultrasonic time of 60 minutes;

[0068] Step 10: Fully mix the R6G dye molecule aqueous dispersion and the PVA aqueous dispersion, wherein the concentration of R6G in the obtained mixed solution is 5wt%, and the concentration of PVA is 2wt%.

[0069] Step 11: Spin-coat the mixed solution onto the substrate on which the aluminum oxide film is deposited, at a spin-coating speed of 2000 revolutions per minute and a spin-coating time of 30 seconds, to form R6G dye molecules@PVA film 4.

[0070] Step 12: Anneal the substrate at 50 degrees Celsius for 30 minutes in an atmospheric environment, and after cooling, a novel surface plasmon polariton laser structure of silver nanowires / R6G dye molecules can be prepared.

[0071] Example 2

[0072] The preparation of the novel surface plasmon polariton laser structure based on silver nanowires / R6G dye molecules in this embodiment is carried out in the following specific steps:

[0073] First, prepare a silver nanowire dispersion. Weigh 10 mg of silver nanowire powder with a diameter of 100 nm and a length of 10 microns, pour it into a 100 ml beaker, then pour 100 ml of deionized water into the above beaker, seal it with a sealing film and put it into an ultrasonic cleaner, adjust the power of the ultrasonic machine to 20 watts, and adjust the time to 5 minutes. After the ultrasound is over, a silver nanowire dispersion that meets the required concentration is prepared. The next step is to clean the silica substrate used, put a square silica single crystal substrate with a side length of 15 mm into the cleaning bracket, put the bracket into a 500 ml beaker, add acetone to the beaker that does not cover the height of the silica substrate, and ultrasonicate for 20 minutes at a power of 200 watts. After the ultrasound is over, use isopropanol and acetone to clean according to the above steps. After cleaning, use high-purity nitrogen to blow dry the residual liquid on the surface of the silica substrate, and put it into a UV ozone treatment machine for treatment for fifteen minutes. After treatment, 50 microliters of the silver nanowire dispersion prepared in the first step was taken with a pipette and dropped onto the silicon dioxide substrate. The spin coater was turned on and the speed was adjusted to 3000 rpm for 30 seconds. After the spin coating was completed, it was placed on a heating table in a nitrogen environment that was heated at 50 degrees Celsius to heat and dry, and the remaining liquid was evaporated. After the liquid was completely evaporated, it was removed and placed in the reaction chamber of the atomic layer deposition system to perform the atomic layer deposition of aluminum oxide. Trimethylaluminum (TMA) was used as the precursor of aluminum oxide to deposit various double-layer Al2O3 nanolaminated films in a customized fixed ALD system. In this process, water was used as a co-reactant, and all depositions were completed at 90°C. Before deposition, the sample was kept at 90°C for 30 minutes. The deposition parameters were: precursor pulse / exposure / clear 0.1s / 30s / 40s (TMA) and 2s / 30s / 40s (H2O). The precursor pulse and purge steps were performed with 25 sccm and 100 sccm nitrogen flows as carrier gas, respectively. Weigh 5 grams of R6G dye molecules, dissolve them in 100 ml of deionized water, and disperse them evenly by ultrasonication at a power of 200 watts for 10 minutes. Weigh 4g of PVA molecules and dissolve them in 100 ml of deionized water, and ultrasonicate them at a power of 200 watts for 20 minutes. After the above two dispersions are prepared, take 10 ml of R6G dye molecule dispersion and 5 ml of PVA dispersion and pour them into a 20 ml solution bottle to obtain a mixed solution. Take out the silicon dioxide substrate in the atomic layer deposition system, put it on the spin coater, take 50 microliters of the mixed solution prepared in the previous step and drop it on the silicon dioxide substrate, start spin coating, the spin coating speed is 2000 rpm, and the image selection time is 30 seconds. After the spin coating is completed, remove the substrate and anneal it on a heating table preheated to 50 degrees Celsius to form a uniform dye molecule @PVA film. Annealing is completed and the device is fabricated.

[0074] Example 3

[0075] The only difference between Example 3 and Example 1 is that the concentration of the silver nanowire dispersion in step 1 is 1 mg / mL.

[0076] Example 4

[0077] The only difference between Example 4 and Example 1 is that the concentration of the silver nanowire dispersion in step 1 is 1.5 mg / mL.

[0078] Example 5

[0079] The only difference between Example 5 and Example 1 is that the diameter of the silver nanowire in step 1 is 80 nanometers.

[0080] Example 6

[0081] The only difference between Example 6 and Example 1 is that the diameter of the silver nanowire in step 1 is 120 nanometers.

[0082] Example 7

[0083] The only difference between Example 7 and Example 1 is that heating is performed at 45 degrees Celsius in step 6.

[0084] Example 8

[0085] The only difference between Example 8 and Example 1 is that heating is performed at 55 degrees Celsius in step 6.

[0086] Example 9

[0087] The only difference between Example 9 and Example 1 is that in step 10, the concentration of R6G is 2 wt % and the concentration of PVA is 1 wt %.

[0088] Example 10

[0089] The only difference between Example 10 and Example 1 is that in step 10, the concentration of R6G is 8 wt % and the concentration of PVA is 4 wt %.

[0090] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a surface plasmon polariton laser, comprising: S1: spin coating the silver nanowire dispersion on the substrate to obtain device 1; S2: heating device 1 for a period of time under an inert atmosphere to obtain device 2; S3: preparing an aluminum oxide film on device 2; S4: spin coating a dye dispersion on the aluminum oxide film and then annealing, wherein the dye dispersion is a mixed solution of R6G and PVA, to obtain the surface plasmon polariton laser.

2. The preparation method according to claim 1, characterized in that: The concentration of silver nanowires in the silver nanowire dispersion in step S1 is 1 to 2 mg / mL; The diameter of the silver nanowires in the silver nanowire dispersion in step S1 is 80 to 120 nanometers, and the length is 8 to 12 micrometers.

3. The preparation method according to claim 1, characterized in that: The spin coating time in step S1 is 20 to 40 seconds, and the spin coating speed is 2000 to 4000 revolutions per minute.

4. The preparation method according to claim 1, characterized in that: The substrate in step S1 is a silicon dioxide single crystal substrate; Wherein, the silicon dioxide single crystal substrate is pre-treated; The pretreatment includes at least one of cleaning, drying and ultraviolet ozone treatment.

5. The preparation method according to claim 1, characterized in that: The heating time in step S2 is 4 to 6 minutes; the heating temperature is 45 to 55 degrees Celsius; The inert atmosphere in step S2 includes at least one of nitrogen, carbon dioxide and helium.

6. The preparation method according to claim 1, characterized in that: The thickness of the aluminum oxide film in step S3 is 5 to 10 nanometers.

7. The preparation method according to claim 1, characterized in that: In step S4, the concentration of R6G is 2 to 8 wt %, and the concentration of PVA is 1 to 4 wt %; The spin coating time in step S4 is 20 to 40 seconds, and the spin coating speed is 1500 to 2500 revolutions per minute.

8. The preparation method according to claim 1, characterized in that: The annealing temperature in step S4 is 40 to 60 degrees Celsius, and the annealing time is 30 to 60 minutes.

9. A surface plasmon polariton laser obtained by the preparation method according to any one of claims 1 to 8.

10. Application of the surface plasmon polariton laser as claimed in claim 9 in the field of nano-optical devices.

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