Preparation system of substrate with high Raman signal gain
By combining femtosecond lasers and microlens arrays to prepare high-density metal nanoparticle lattices and graphene arrays, the problem of insufficient Raman signal gain in existing technologies is solved, achieving low-cost and efficient Raman signal enhancement.
Patent Information
- Application Number
- CN202520282747.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2035-02-21
AI Technical Summary
Existing technologies make it difficult to fabricate uniform metal micro/nano structures on a large scale at low cost to enhance Raman signals, and the gain from the surface plasmon effect of metal thin films is limited.
A high-density metal nanoparticle lattice was prepared by combining a femtosecond laser, a frequency doubling unit, and a microlens array. Combined with a graphene array, the graphene array was formed by reducing graphene oxide with a femtosecond laser, thereby enhancing the Raman signal.
A high-gain Raman signal was achieved by reducing the fabrication cost through surface plasmon physical enhancement and charge transfer chemical enhancement, resulting in uniform metal micro/nano structures.
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Figure CN223960693U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of spectral analysis and femtosecond laser-induced synthesis technology, specifically to a system for fabricating a substrate with high Raman signal gain, and more particularly to a technique for fabricating periodic micro / nano structures using femtosecond laser-induced synthesis. Background Technology
[0002] Raman spectroscopy, often referred to as the fingerprint spectroscopy of molecules, has significant applications in environmental, medical, and biomolecular research fields. Particularly in disease detection, rapid and accurate virus detection is a crucial step for early treatment and preventing viral spread. The advent of handheld Raman spectrometers has made rapid and accurate virus detection possible. Because Raman spectroscopy originates from molecular scattering, its signal intensity is four orders of magnitude lower than that of absorption and fluorescence spectroscopy. Enhancing the molecular Raman signal can effectively address this issue. Typically, the surface plasmon resonance effect of metal thin films is used to enhance the molecular Raman signal. However, the surface plasmon resonance effect of metal thin films has limited gain on Raman signal intensity. Fabricating metal thin film structures with micro / nano structures can further excite the surface plasmon resonance effect, thereby increasing the gain on the Raman signal. However, the large-area fabrication of uniform metal micro / nano structures is costly.
[0003] Therefore, there is an urgent need for a simple, convenient, and low-cost method to prepare reinforced substrates with ordered metallic Wiener array structures. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a system for fabricating a substrate with high Raman signal gain. By combining a femtosecond laser, a frequency doubling unit, and a microlens array, the fabricated substrate has a high-density metal nanoparticle lattice. The metal nanoparticle array can achieve physical enhancement effects of surface plasmons, as well as chemical enhancement effects of charge transfer. The fabricated graphene array can be widely used in the detection and analysis of Raman signals in the fields of medicine, biology, and chemical analysis.
[0005] The objective of this utility model is achieved through the following technical solution:
[0006] A system for fabricating a high-gain Raman signal substrate for forming a metal array on a substrate is characterized by comprising a femtosecond laser, a frequency doubling unit, and a microlens array, wherein the femtosecond laser is used to generate a femtosecond laser, the frequency doubling unit is disposed in the optical path of the femtosecond laser to combine infrared femtosecond lasers to generate a deep ultraviolet femtosecond laser, and the deep ultraviolet femtosecond laser is focused by the microlens array into a laser dot matrix for forming a metal array on the substrate.
[0007] A telescope system is provided between the frequency doubling unit and the microlens array. The telescope system is used to expand the deep ultraviolet femtosecond laser beam into a light spot with uniform field intensity and uniformly cover the microlens array.
[0008] The telescope system uses deep ultraviolet lenses with a combination of long and short focal lengths.
[0009] The frequency doubling unit includes an attenuator. The femtosecond laser light passes through the attenuator to the reflector M1, where it is directed to a beam splitter and divided into two beams. One beam passes through another attenuator and is converted into near-ultraviolet light by a first frequency doubling crystal. This near-ultraviolet light is then directed to a delay line through a reflector M3. The other beam passes through a reflector M2, a dichroic mirror M4, and the frequency-doubled light that also passes through the dichroic mirror M4, and together they enter a second frequency doubling crystal for frequency combination to obtain the deep ultraviolet femtosecond laser.
[0010] The substrate is placed on a 3D console.
[0011] The advantages of this utility model are:
[0012] 1) The use of femtosecond lasers, with their high field strength, is conducive to the efficient reduction of graphene oxide and the formation of graphene arrays with excellent structure.
[0013] 2) Using frequency-doubled deep ultraviolet lasers can significantly reduce edge diffraction effects, resulting in an array structure with neat edges and enhancing the surface plasmon effect of graphene.
[0014] 3) Using microlens arrays, but not limited to microlens arrays, can yield structural graphene arrays.
[0015] 4) Graphene arrays with uniform structure, controllable range, and excellent performance can be prepared. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the system configuration of this utility model;
[0017] Figure 2 A schematic diagram of an 800 nm femtosecond laser frequency doubling unit;
[0018] Figure 3 A schematic diagram of the deep ultraviolet laser beam expander and microlens focusing optical path;
[0019] Figure 4 This is a schematic diagram of a controllable dot matrix.
[0020] Figure 5 This is a schematic diagram of shape-controllable focusing.
[0021] Figure 6 A schematic diagram showing the reduction of solid-phase graphene oxide film to graphene;
[0022] Figure 7 This is a schematic diagram of liquid-phase induced aggregation of metal nanoparticles. Detailed Implementation
[0023] The features and other related features of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate the understanding of those skilled in the art:
[0024] like Figure 1-7 As shown in the figure, the labels represent: femtosecond laser 1, frequency doubling unit 2, microlens array 3, and substrate 4, respectively.
[0025] Example: Figure 1 As shown, the fabrication system for the high-gain Raman signal substrate in this embodiment includes a femtosecond laser 1, a frequency doubling unit 2, and a microlens array 3, used to form a metal array on a substrate 4. The substrate 4 is fixed on a three-dimensional displacement stage, and by adjusting the position of the substrate 4, SERS arrays of different sizes and ranges can be obtained.
[0026] First, a femtosecond laser 1 is used to generate a femtosecond laser, which is then introduced into a frequency doubling unit 2. Utilizing the high field strength of the femtosecond pulse laser, it can be focused to induce the reduction of graphene oxide. Graphene can be prepared by reducing graphene oxide after the femtosecond laser is focused.
[0027] In this embodiment, the femtosecond laser 1 is an 800 nm, 90 fs pulsed laser.
[0028] like Figure 2 As shown, frequency doubling unit 2 uses a nonlinear optical crystal to frequency the infrared femtosecond laser and generate a deep ultraviolet femtosecond laser, which can convert 800nm near-infrared light into 266nm deep ultraviolet light.
[0029] Specifically, the 800nm laser first passes through an attenuator (used to adjust the laser power), and then through a reflector M1 to a beam splitter BS. The 800nm light is split into two beams. One beam passes through the attenuator and then through the first frequency-doubled crystal BBO, converting it into 400nm near-ultraviolet light. This beam is then guided through a delay line (used to adjust the sum-frequency process) through a reflector M3. The other 800nm beam passes through a reflector M2, a dichroic mirror M4 (high reflectivity at 400nm, high transmittance at 800nm), and the 400nm frequency-doubled light reflected by the dichroic mirror M4, and together they enter the second frequency-doubled crystal BBO for sum-frequency generation. By adjusting the delay line, the 800nm and 400nm light can be sum-frequencyd in crystal BBO2 to obtain a 266nm deep ultraviolet femtosecond laser.
[0030] In this embodiment, the frequency doubling unit 2 can generate deep ultraviolet femtosecond lasers in other wavelength bands by adjusting the input light.
[0031] Next, the deep ultraviolet femtosecond laser is introduced into the microlens array 3. For example... Figure 3 As shown, before entering the microlens array ML, the 266 nm deep ultraviolet femtosecond laser is first expanded using a telescope system to ensure uniform distribution within the laser spot area. The 266 nm deep ultraviolet femtosecond laser is further expanded using ultraviolet high-transmittance lenses L1 and L2, with long and short focal lengths respectively, to achieve uniform light field coverage of the microlens array 3, forming a laser spot with uniform field strength. The microlens array 3 can be viewed as a collection of many tiny lenses, each capable of focusing to form a uniformly intense laser dot array on the focal plane.
[0032] In this embodiment, by selecting the shape of the microlens array 3, different shapes of focused lenses can be output. Figure 5 (As shown).
[0033] Finally, the substrate 4 is moved to the focusing plane of the microlens array 3 using a three-dimensional displacement stage. By controlling the three-dimensional displacement stage, the size and range of the lattice on the substrate 4 can be controlled, such as... Figure 4 As shown.
[0034] In this embodiment, substrate 4 can be made of different materials to achieve the preparation of SERS substrates of different materials.
[0035] When this embodiment is applied, the following examples are included:
[0036] Fabrication of graphene SERS arrays: A silicon wafer is selected as the substrate, and a graphene oxide film is prepared on the silicon substrate using spin coating. The graphene oxide is then reduced to graphene using a femtosecond ultraviolet laser, allowing the fabrication of graphene arrays at the focal plane. Figure 6 As shown; fabrication of a silver SERS array. Femtosecond lasers can induce the aggregation of metal nanoparticles. Quartz was chosen as the substrate, and the quartz substrate was placed in a solution of silver nanoparticles. By adjusting a three-dimensional displacement stage, the quartz substrate was moved to the focal plane of the microlens array. The silver nanoparticles aggregated at the focal point, thus realizing the fabrication of a silver SERS substrate, as shown. Figure 7 As shown.
[0037] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.
Claims
1. A system for fabricating a high-gain Raman signal substrate, used to form a metal array on a substrate, characterized in that: It includes a femtosecond laser, a frequency doubling unit, and a microlens array, wherein the femtosecond laser is used to generate a femtosecond laser, the frequency doubling unit is disposed in the optical path of the femtosecond laser to combine infrared femtosecond lasers to generate a deep ultraviolet femtosecond laser, and the deep ultraviolet femtosecond laser is focused by the microlens array into a laser dot matrix for forming a metal array on a substrate.
2. The fabrication system for a high-gain Raman signal substrate according to claim 1, characterized in that: A telescope system is provided between the frequency doubling unit and the microlens array. The telescope system is used to expand the deep ultraviolet femtosecond laser beam into a light spot with uniform field intensity and uniformly cover the microlens array.
3. The fabrication system for a high-gain Raman signal substrate according to claim 2, characterized in that: The telescope system uses deep ultraviolet lenses with a combination of long and short focal lengths.
4. The fabrication system for a high-gain Raman signal substrate according to claim 1, characterized in that: The frequency doubling unit includes an attenuator. The femtosecond laser light passes through the attenuator to the reflector M1, where it is directed to a beam splitter and divided into two beams. One beam passes through another attenuator and is converted into near-ultraviolet light by a first frequency doubling crystal. This near-ultraviolet light is then directed to a delay line through a reflector M3. The other beam passes through a reflector M2, a dichroic mirror M4, and the frequency-doubled light that also passes through the dichroic mirror M4, and together they enter a second frequency doubling crystal for frequency combination to obtain the deep ultraviolet femtosecond laser.
5. The fabrication system for a high-gain Raman signal substrate according to claim 1, characterized in that: The substrate is placed on a 3D console.