阅读说明：本技术 一种利用石墨烯纳米带阵列光栅获取频率调制偏振激光的方法 (Method for obtaining frequency modulation polarized laser by utilizing graphene nanoribbon array grating ) 是由 蔡金明 许望伟 郝振亮 卢建臣 于 2020-05-28 设计创作，主要内容包括：本发明涉及低维纳米材料以及光学技术领域,具体涉及一种利用石墨烯纳米带阵列光栅获取频率调制偏振激光的方法,包括以下步骤,(1)在干净的Au(111)单晶近邻台阶面如Au(7 8 8)和Au(11 11 12)单晶面为基底采用自上而下法制备石墨烯纳米带阵列；(2)将制备的石墨烯纳米带阵列转移到基底上,制成光栅；(3)采用偏振拉曼散射光谱标定光栅y轴和x轴；(4)将任意频率激光照射在光栅上,光栅反射出调制频率的偏振激光。本发明采用原子级精确石墨烯纳米带,基于此纳米带的拉曼散射对激光频率进行调制,获得激光具有窄的带宽；对任意频率的激光都能进行调制,潜在应用广泛；光栅调制激光不需要额外电源,使用方便。(The invention relates to the technical field of low-dimensional nano materials and optics, in particular to a method for acquiring frequency modulation polarized laser by utilizing a graphene nanoribbon array grating, which comprises the following steps of (1) preparing a graphene nanoribbon array by adopting a top-down method on the surface of a clean Au (111) single crystal adjacent step, such as Au (788) and Au (111112) single crystal face, as a substrate; (2) transferring the prepared graphene nanoribbon array to a substrate to prepare a grating; (3) calibrating a y axis and an x axis of the grating by adopting a polarized Raman scattering spectrum; (4) laser with any frequency is irradiated on the grating, and the grating reflects polarized laser with modulated frequency. According to the invention, an atomic-level accurate graphene nanoribbon is adopted, and the laser frequency is modulated based on Raman scattering of the nanoribbon, so that the obtained laser has a narrow bandwidth; the laser with any frequency can be modulated, and the potential application is wide; the grating modulation laser does not need an additional power supply, and is convenient to use.)

1. A method for obtaining frequency modulation polarized laser by utilizing a graphene nanoribbon array grating is characterized by comprising the following steps:

step 1: preparing an atomic-level accurate graphene nanoribbon array by a bottom-up method by taking a clean Au (111) single crystal close to a step surface as a substrate;

step 2: transferring the prepared graphene nanoribbon array onto a substrate to prepare a grating;

and step 3: calibrating a y axis and an x axis of the grating by adopting a polarized Raman scattering spectrum;

and 4, step 4: and irradiating laser on the grating, and collecting the Raman scattered light to obtain polarized laser with modulated frequency.

2. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: in the step 1, the Au substrate is a crystal face of a single crystal with a close step, the crystal face index of which is near to (111).

3. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: in the step 1, a bottom-up method is adopted to grow the graphene nanoribbon array.

4. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: and transferring the graphene nanoribbon array to a using substrate after growth to prepare the grating.

5. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: and modulating the laser frequency based on the Raman scattering of the graphene nanoribbon array.

6. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: the modulated light is still the wanted dry light.

7. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: the grating constant d is in nanometer level and is far less than the modulated frequency, so that the modulated scattered light only has grating 0-level diffraction fringes, i.e. the light intensity is concentrated in a single angle.

8. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: based on the polarization of the graphene nanoribbon array Raman scattering, the modulated laser is polarized light.

9. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: the laser with any frequency can be modulated, and the changed frequency is fixed.

10. The method for obtaining the frequency-modulated polarized laser by using the graphene nanoribbon array grating according to claim 1, wherein the method comprises the following steps: the grating may operate in a variety of environments.

Technical Field

The invention relates to the technical field of nano materials and optics, in particular to a method for obtaining fixed-frequency polarized laser by utilizing a graphene nanoribbon array.

Background

The laser technology plays an important role in the present science and technology, and the laser has important application in the fields of photoelectric communication, military, industry and the like, and is an indispensable research tool in scientific research. In the process of using laser light, it is always important to have a controllable modulation of the laser light.

In scientific research, less high-intensity laser is used, more laser light sources with lower intensity are used, photon energy has the greatest influence on laser properties at the moment, the energy E = h ν of the photon, namely the photon energy is in direct proportion to the frequency, so that the modulation of the frequency of the laser represents the linear regulation of the photon energy, and the regulation of the photon energy has important significance on the application of the laser in scientific research.

Disclosure of Invention

In order to expand the method of laser frequency modulation, the invention provides a novel laser frequency modulation method which is convenient to use and has wide application range, can obtain polarized laser for modulating fixed frequency, and is mainly solved by the following technical means.

A method for obtaining frequency modulation polarized laser by utilizing a graphene nanoribbon array grating comprises the following steps:

(1) preparing an atomic-level accurate graphene nanoribbon array by a bottom-up method by taking a clean Au (111) single crystal close to a step surface as a substrate;

(2) transferring the prepared graphene nanoribbon array to a transparent thin substrate to prepare a grating;

(3) the y-axis and x-axis of the grating are calibrated by polarized raman measurements.

(4) Irradiating laser onto the grating, and collecting the Raman scattered light to obtain polarized laser with modulated frequency;

the invention has the beneficial effects that: the laser with any frequency can be subjected to frequency modulation, and the potential application is wide; modulation of a fixed frequency, i.e. changing of a fixed energy, is of great significance in application; the obtained laser has good coherence and narrow bandwidth; the laser is modulated by the grating mode, no extra power supply is needed for energy supply, the influence on an optical path is small, and the use is simple and convenient.

Drawings

FIG. 1 is a schematic diagram of a grating preparation process and operation.

Fig. 2 is a schematic diagram of preparation of an N =7 armchair graphene nanoribbon array.

Fig. 3 is a G peak intensity polarization diagram of graphene nanoribbon array polarization raman.

FIG. 4 is a graph of the diffraction intensity distribution on the x-axis.

Detailed Description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described with reference to specific embodiments, which are not intended to limit the present invention.

A method for obtaining frequency modulation polarized laser by utilizing a graphene nanoribbon array grating comprises the following steps:

(1) preparing an atomic-level accurate graphene nanoribbon array by a bottom-up method by taking a clean Au (111) single crystal close to a step surface as a substrate;

(2) transferring the prepared graphene nanoribbon array to a transparent thin substrate to prepare a grating;

(3) the y-axis and x-axis of the grating are calibrated by polarized raman measurements.

(4) Irradiating laser onto the grating, and collecting the Raman scattered light to obtain polarized laser with modulated frequency;

for better illustration, the direction perpendicular to the graphene nanoribbon array growth in the grating plane is named as the x-axis, and the direction perpendicular to the graphene nanoribbon array growth in the grating plane is named as the y-axis.

The graphene nanoribbon is prepared on the surface of Au by a bottom-up method, so that the graphene nanoribbon with accurate atomic scale can be prepared, the Raman scattering peak position of the graphene nanoribbon is fixed, and the graphene nanoribbon has narrow half-height peak width.

In an ultrahigh vacuum environment, DBBA is selected as a precursor, and an N =7 armchair-type graphene nanoribbon array is epitaxially grown on a clean Au (111112) step surface, so that the nanoribbon array is shown in fig. 2.

And transferring the graphene nanoribbon array to a PMMA substrate to prepare the grating.

Calibrating the y axis and the x axis of the grating through polarization Raman measurement, and irradiating the grating by using polarization laser with the wavelength of 532nm at different angles to detect the Raman scattering intensity; the signal intensities of the different angle polarized lights are shown in fig. 3, so the angle with the strongest raman intensity is marked as the y-axis, and the x-axis is perpendicular to the y-axis.

N =7 armchair type graphene nanoribbon Raman scattering G peak position is independent of incident laser wavelength, and for any frequency v incident laser, the modulation fixed frequency v' = v + ck/2 can be obtained through the grating

Wherein c is the speed of light, k =1596 cm^-1。

N =7 armchair graphene nanoribbons have a width of 0.73 nm and a nanoribbon pitch of around 1 nm in an array grown on Au (111112). Namely, the grating a =0.73 nm and d =1 nm prepared by the graphene nanoribbon array. The intensity distribution formula of the diffraction grating in the x-axis direction is as follows:

whereinDIs the diffraction factor:

Iis an interference factor:

n is the number of participating gratings, if the diameter of an incident laser spot is 1 mm, N =10^6 can be obtained from d =1 nm, and the data are substituted into an intensity distribution formula to obtain an intensity distribution curve as shown in FIG. 4; it can be seen that all the light intensity on the x-axis is concentrated onIn the angle of (c).

The Raman scattered light has certain scattering in the y-axis direction, only the scattered light generated by the Raman effect can be generated at the laser spot, the scattered light can be regarded as a point light source, the scattering generated by the point light source can be easily converged by a lens, and the frequency-modulated polarized laser is obtained after the point light source is converged.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the concept and the protection scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the concept of the present invention shall fall within the protection scope of the present invention.