| Whispering Gallery optical microcavities due to its high quality factor and ultra-small mode volume and other characteristics is much widespread concerned in recent years,which has become the new topic of the research areas of modern micro-optics and cavity quantum electronics.The attention of microcavity surface plasmon wave whispering gallery modes due to their potential applications in the detection of biological macromolecules has been paid,which serve as the focus of the discussions in this article.And through theoretical simulation and experimental method,the microdisk laser has been studied.The main research work and conclusins in the atricle are as follows.First of all, a new microdisk laser was designed,which semiconductor material serve as its core structure.The basic idea of the Finite Element Method was used to theoretically calculate and analyse the whispering gallery mode.The device was made up InGaAsP materials plated silicon dioxide dielectric film on its surface,and then plated with nobile metal gold film to form a composite cavity structure.This designed structure reduces the loss of the device to improve the characteristics of its parameters.The Finite Element Method was used to solve the weakness all vector of Helmholtz equation which described the cavity mode distribution,and the magnetic field distribution of the whispering gallery optical-electric modes and surface plasmon wave mode of the device are obtained;the relationship between the quality factor,mode volume and other parameters and its various structural parameters were analysed with detail.The calculation results show that good linear relationship between the mode index and the resonant frequency and quality factor in a wide range are existing;for the-surface plasmon wave mode,the mode index and mode volume present a relationship of quadratic curve corresponds to the minimum mode volum Vmode=1.6×10-18m3at M=65.Meanwhile,the calculated results show that the quality factor of the device under the same scales higher2to3times than the one of the other structures,and up to5400near1500nm,and has a very small mode volume,up to the order of magnitude10-18m3.In addition, calculations show that only a specific thickness of the dielectric layer and metal layer to exert significant influence on the device quality factor.Secondly,the work of experimental aspects in this article includes two aspects First,the wet etching technology process was used to fabricate a silica microdisk cavity,which were discussed in detail. Trial and error,a relative ideal microdisk was made,and the radius of the disk is R=18.8mm,the thickness of the disk is T=2.6mm, the average diameter of the pillar of the disk is D=5.0mm,and the height of the pillar is H=8.6mm.Sceond, in order to obtain specific knowledge of the device performance,ist coupling characteristics was tested.The test results show that there is a large gap between the theoretical calculation of the quality factor and the one of actual measured.The quality factor of the device is4.7×103infered from the test,while the quality factor of the device under the same scales is3.8×106by Theoretically calculated.The gap is mainly from the roughness of the surface,especially its rough edge which caused scattering loss and the heterogeneity of the disk symmetry which caused the escape loss.Producing high-quality microdisk lasers is still a much technical challenges.In summary,the highlights of this paper is to propose a new structure of cavity,it has a larger quality factor than other structures2to3times.For the surface plasmon wave mode of the designed device,the relationship between ist resonance wavelength and the effective refractive index is perfectly linear in a wide range,and this feature is promising to apply such as those based on the density change detection.Furthermore,we discuss the relationships of the device structure and the quality factor which may be the guiding rules for the actual fabrication of the microdisks. |
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