Prepare Fiber Random Laser By Siphonage

Random laser is a new type laser,based on the optical feedback through particle scattering.Different with conventional laser,random laser does not need resonant cavity,and the dimension of random laser is less more than the traditional laser.For random laser,photons are amplified after multiple scattering by particles in the active regions.However,in random laser,the emission wavelength and angle are not controlled.In order to reduce the divergence angle,the fiber-optic random lasers are designed and fabricated.As the extension of powder,liquid and film random lasers,they have attracted more and more attention in recent years.The structure of one-dimensional fiber makes the application of random lasers have outstanding characteristics,and the excellent flexibility of polymer makes fiber-optic random lasers have more applications.When the light propagates through the random medium,the transmitted light intensity will gradually decrease with the increase of propagation depth.If the medium concentration is increased to shorten the average free path of scattered light wave,the transmitted light will decrease exponentially.When the average free path reaches the critical point,the light propagation in the medium stops,and the photons are localized in a certain position,resulting in strong localization.So the difficulty of long-distance random laser can be seen,but its important application value stimulates our research interest.Because of its outstanding advantages,solid-state random lasers have shown more and more important research value.As a three-dimensional solid-state random laser,fiber random laser has important theoretical significance and application for the research of basic laser physics,random scattering and single-mode,narrow linewidth fiber laser.The advantages of random laser,such as simple structure,low cost,narrow linewidth and low frequency noise,will provide an important guarantee for the application research of high-speed and large capacity fiber communication system,long-distance fiber sensing and laser imaging.The main research direction is to use the advantages of fiber random laser to improve the performance of solid-state random laser.At the same time,in the process of theoretical analysis and experiment,we continue to deepen and improve the understanding of the essence of fiber random laser.The fiber type random laser has experienced the transition from incoherent to coherent,strong random structure to weak disordered structure,and the research on the regulation of the wavelength length of the fiber type random laser is still in the initial stage.The microstructure of the fiber is profound and important to the mode transmission,threshold and wavelength tuning of the fiber.In the traditional laser,the lumen limiting photon also determines the basic characteristics of the laser mode,such as wavelength,emission mode,directivity and polarization.If the microstructure of the fiber is combined with the lumen theory,the emission wavelength is limited and selected,which has a distinct guiding significance for the wavelength regulation of the optical fiber random laser.The main research contents of this paper are as follows:1.Paper-based R6 G concentration continuous change of random laser regulationThe random laser does not need traditional resonant cavity,and is at the cost of the direction,laymen,emergent band measures.Generally,the tuning of random laser can be divided into mechanical control,structure regulation and molecular regulation.The mechanical tensile needs to be met for the flexible base.Structure control is to be designed ahead,and cannot be changed once the design is complete.The molecular regulation of external environment the demand is higher.In this paper,a simple method is proposed to control the random laser,and the regulation of the follow-up optical fiber type of random laser guiding significance.2.Basic principle and operation flow of siphon methodThe concentration of active material has a great effect on the random lasing output.In this work,the dye R6 G is investigated from the discretization sites to the continuous changes in the trend.Based on the premise of the photon localization theory,the R6 G concentration for random laser has a function on half peak width,threshold,the output light intensity.3.Basic principle and operation flow of siphon methodThe basic principle in a siphon tube is liquid pressure difference with atmospheric pressure,and the driving force of the siphon phenomenon mainly is the atmospheric pressure.Sometime,the surface tension of the liquid has a contribution to siphon phenomena.In this work,siphon method is introduced in details in the operation process in the process of preparation.4.Study on photon localization of cylindrical fiber polymer random laserIn 1958,Anderson Localization model was established,and was introduced as photon Localization phenomenon for the random lasing output.The columnar fiber polymer of random laser is fabricated,and the sidewall scattering light is investigated.Based on the intensity of light transmitted in the columnar fiber,the concentration of dye,the outer wall material and fiber core component,optical path shows a critical value.The scattering effect is influence by the critical optical path.When the critical condition was reached,the intensity of the emitted light became stronger,the collimation became better,and the sidewall scattering became weaker,which further verified the theory of photon localization.5.Research on the Regulation characteristics of Air Bubble fiber polymer random laser based on the longitudinal mode theory of resonator cavityThe random laser with air bubbles is designed.The siphon method different from traditional particle scattering using two kinds of incoherent feedback(wall + polymer)provide optical feedback at the same time,by adjusting the concentration of the gain medium,get decimeter order of magnitude in the length of optical fiber type of random laser,ultrasonic method is used to make X micro ring polymer structure and the air bubble is evenly distributed,the random laser system has high efficiency and narrow bandwidth,the advantages of dual spectral tuning range.The X-type micro-ring cavity polymer random laser can be observed obvious double mode output,the experiment and the theory are in good agreement,promoting the theoretical understanding of mode selection in the weak disordered structure,and this work design scheme,for the regulation and optimization of multi-mode output fiber random laser has a guiding significance.