Research On MoS₂-based Stimulated Brillouin Scattering Effect Gain Enhancement

As one of the greatest inventions since the 20th century,the birth of laser has played an important role in the research of traditional physical optics,thus promoting the related research of optical nonlinearity.In optical nonlinear phenomena,Stimulated Brillouin Scattering has attracted extensive attention from researchers all over the world because of its high probability of occur-rence and inelastic optical energy transfer,leading to many applications of high-performance photonic devices based on brillouin scattering light char-acteristics.In order to further develop high-efficiency SBS applications,it is very important to find Brillouin medium that can produce a large SBS gain effect.However,the SBS gain in ordinary optical fibers is usually small.If the application of photonic devices with higher SBS gain is to develop,the length of optical fibers in the optical path needs to be extended to a large ex-tent.In this way,some optical restrictions like dispersion will be indirectly introduced,thus affecting the overall performance of the device.At present,studies based on high-nonlinear sulfide fiber,special waveguide structure and micro-ring resonator can enhance SBS effect to some extent.However,they all have the limitations of complex structure design,high production cost,great insertion loss and so on.As a result,researchers are inclined to place more attention on improving the SBS gain with new exploration.Recently,molybdenum disulfide,as a representative of the transition metal sulfide fam-ily,has been widely valued for its unique photoelectric properties,such as variable band gap,high electron mobility and special optical nonlinearity,etc.However,according to the existing research,the research on the opti-cal nonlinear characteristics of MoS₂is only limited to the elastic optical nonlinear phenomena.The study of inelastic optical nonlinearities such as Stimulated Brillouin Scattering is still a field to be explored.Therefore,on the basis of considering the strong stimulated brillouin scattering effect of sulfides,one of the members from the same sulfide group as MoS₂,and the physical size of MoS₂which can meet the requirements of photonic device integration,this thesis,based on the nonlinear study of 2D layered materials,takes MoS₂as the main research object and explores its optical nonlinear SBS effect,including the preparation and transfer of 2D materials,the character-istic measurement of optical medium,the targeted SBS gain measurement structure design and the analysis of experiment result.First of all,in order to meet the observation conditions of SBS effect and break the limitations of traditional observation methods of SBS effect in materials,two kinds of transferred optical fibers are prepared in this thesis to observe the SBS gain enhancement in 2D materials.The first transferred optical fiber uses mechanical exfoliation method to obtain three main 2D materials,and transfers the 2D materials to the end facet of fiber core by directly bonding based on PDMS.The second transferred optical fiber uses CVD growth method to obtain MoS₂material,and transfers MoS₂onto the side of micro-optical fiber core based on wrapping method.In addition,the quality and basic optical properties of two kinds of transferred optical fibers are tested respectively,and good results are obtained.Then,this thesis studies the corresponding SBS gain enhancement of two fiber structures with transfer materials.The SBS test device was de-signed,and the SBS gain enhancement effect was tested and qualitatively analyzed in this thesis.For the first time,it is found that under the interac-tion between light and MoS₂with only nanometer thickness and micrometer length,significant SBS gain enhancement can be generated and observed.Meanwhile,the line width of MoS₂shows a trend of wide SBS spectrum characteristics.This provides a great prospect for the application of new in-tegrated photonic devices based on SBS gain in the future.