The Study Of The Random Laser Properties Of The Microcavity In The Optical Waveguide Structure

Light scattering is a common physical phenomenon of nature,especially in optical waveguide,it has two sides in the optical waveguide,on the one hand,can cause additional loss,on the other hand,also can play a useful role,such as in the use of scattering in the waveguide with gain feedback form random laser.A random laser is a new type of laser,which relies on the scattering of light to provide feedback and form a feedback loop to achieve laser excitation.Compared with the traditional laser,it has a simple structure and does not require high precision cavity,high control degrees of freedom,in areas such as medical,biological and imaging has potential application value.This paper presents a novel microcavity random laser based on cylindrical waveguide structure,and controls the random laser.Random laser is put forward in a cylindrical quasi optical waveguide structure,namely by quartz capillary coating disordered nanoparticles in inner layer,and using laser dye as gain medium filling in fiber core.This design is helpful to reduce the random laser with tunable threshold,output,and the structure of the scattering layer and laser dye separation,with the traditional random laser can't separate scattering medium and laser dye,compared to a more stable and reusable.The details are as follows:At first is for numerical simulation of optical fiber structure: using cold chamber analysis(gain medium gain coefficient is zero),the introduction of electric dipole in the structure as a light source,and change the number of scattering particles,get the influence law of scattering particles in the output spectrum features such as;Observed from the cold chamber spectrum part eventually forming laser maser,corresponding to the electric field distribution in different regions appears bright speckle,namely the photon localization effect;On the basis of this,the gain medium(not zero gain medium coefficient)is introduced,and the output model of the structure is further explored.We then introduced a single silver nanoparticle in the gain media structure,aiming to control the random laser.Found that nano silver point for system caused by the photon localization interference will lead to the disappearance of the laser mode or other mode,the output mode,strength is sensitive to the position of the nanoparticles,proves that the addition of silver nanoparticles point can be implemented for random laser good regulation,whereas by random laser output spectrum changes can also be used to locate the nanometer level.Finally,the experiment made the random laser samples,and by changing the gain medium refraction and scattering medium particle radius,analyzed the random patterns of laser output intensity and wavelength shift change rule.