Generation,Modulation,and Application Of Complex Laser With Liquid-Core Waveguide Microcavity

Disordered boundary structures and random scattering structures in optical media have gained a lot of attention as an excellent platform for studying complex optical events.In particular,complex lasers generated under active and nonlinear conditions have been an important branch of the laser field.Due to the randomness in time,space,or spectrum,complex lasers are usually difficult to be collected and controlled efficiently.However,low-dimensional waveguide structures represented by optical fibers can provide compact microcavity confinement and axial optical waveguide constraints for the generation and coupling of complex lasers,which provide new ideas for research and application innovation in this field.Therefore,the research related to complex lasers in fiber waveguide structures has become a cutting-edge academic direction.In addition,the rapid development of materials,micro and nano,artificial intelligence,and other disciplines has brought breakthroughs in the research of the generation,modulation,and application of complex lasers.Meanwhile,random lasers,chaotic lasers,and deformed microcavity lasers,typical representatives of complex lasers,are also developing in new directions.Under the constraints of low-dimensional waveguides such as optical fibers,complex lasers are generated by the combined effects of gain,random feedback,nonlinearity.However,the research on the mechanism,modulation methods,and application expansion of complex lasers still needs to be improved.There are several critical issues that remain to be resolved.The first is the systematic analysis of the generation mechanism for complex lasers in disordered microcavities,especially the study of generation methods,coexistence mechanism,and interaction mechanism of complex lasers in low-dimensional disordered systems such as fiber waveguide;the second is the modulation of complex laser in disordered microcavities,which usually has unpredictable output and disordered parameter.On the one hand,it increases the difficulty of regulating the output,on the other hand,it also introduces more degrees of regulatory freedom.Effective tuning of such complex lasers has become a hot challenge for research in this field.Finally,for new applications of complex lasers,their unique output characteristics and modulation methods will bring breakthroughs in their applications in the information field,which will greatly advance the development of photocommunication,storage,display,and other fields.In view of the above background,the liquid core fiber complex laser is taken as the research object in this dissertation,which is provided by a hollow-core fiber(HCF)with compact radial microcavity structural constraints and axial optical waveguide effect,and further introduces liquid microfluidic environment such as scattering and gain medium inside the cavity to provide light-matter interaction conditions for the generation and modulation of complex laser.On this basis,this research investigates the effects of disordered feedback from different cavity boundaries and intracavity scattering media on laser excitation and coexistence mechanisms and explores the effects of light injection,external field effects,and nonlinear effects on the effective methods for regulating laser output.Finally,new laser devices and information applications are explored and combined with the output characteristics.The main research contents and findings of this dissertation are summarized as follows:(1)Generation of complex lasers in liquid-core fiber microcavities.For the case of a disordered boundary cavity without scattering,the inner cladding random scattering structure of the HCF is introduced to construct a random fiber microcavity.Further,the cavity is filled with a liquid gain medium without scattering effects.Through the profound analysis of the laser generation mechanism,the relationship between multiple mechanisms of random laser and disordered cavity boundary is revealed from theoretical and experimental perspectives,respectively.For the case of boundary-ordered cavities with scattering,a regular microcavity-constrained liquid-core whispering gallery mode(WGM)laser is constructed by filling an HCF with a high-refractive-index dye liquid crystal.Through the study of the effect of liquid crystal molecule scattering assistance on the WGM microcavity laser,it is demonstrated that the scattering of liquid crystal molecules can couple the fluorescence in the cavity into the WGM laser modes and establish a non-zero momentum optical waveguide coupling channel in the fiber axis,which has a significant enhancement effect on laser generation and output.For the coexistence of boundary disorder and intracavity scattering,a boundary feedback-assisted fiber microcavity laser is constructed.By varying the cavity length to regulate the contribution of cavity boundary feedback and intracavity scattering medium to the laser,a complex laser output with multiple mechanisms convertible is obtained.Based on the above researches,the scattering-assisted WGM laser in fiber microcavity is first proposed and realized,and the multi-mechanism,convertible complex laser output is obtained,which greatly enrich the theoretical systems and implementation methods of complex laser.(2)Modulation of complex lasers in liquid-core fiber microcavities.For spatial property modulation,ordered liquid crystal molecules are introduced into the fiber microcavity.The spatial soliton excitation,coupling,and reception methods are proposed from theoretical and experimental perspectives using material nonlinear effects and optical modulation means,respectively.Then,by investigating the steering characteristics of optical solitons in the microcavity under electric field modulation,the controlled excitation of different spatial modes in the microcavity is realized.For the spectral property modulation,a hybrid electrically controlled programmable spectral laser is proposed,which uses the electric field to control the disordered states of liquid crystal molecules in the cavity in different regions and achieves a definable output for the output spectrum.The above methods provide an effective way for the functionalized output and flexible control of microcavity lasers in low-dimensional waveguide systems.(3)Research on information transmission and encryption applications of complex lasers in fiber microcavities.The realization method of synchronous output between coherent random lasers is studied.Based on the injection-locking principle of masterslave lasers,the single-shot random spectral synchronization between two microcavity nodes is realized theoretically and experimentally.It can be extended to the spectral synchronization of random microcavity lasers cascaded in a multi-node network,which provides an effective way to generate,transfer,and share random information.The information encryption method of a decentralized network based on complex lasers is studied.The bistable logic output of the regular and random laser is realized in the scattering-assisted liquid core fiber microcavity laser.Using the photothermal effect to control the bistable logic state of the random laser output,a method for random key generation,encryption,and transmission for decentralized networks is proposed combined with the spectral randomness and intensity bistable characteristics of the laser output.The proposed and verified application methods can be used as prospective cases for functional expansion of microcavity complex lasers,and lay a foundation for multiscenario application of networked interconnection of photons in disordered systems.