Whispering Gallery Mode Optofluidic Laser And Biosensing

As a new type of laser,a cell laser refers to the lasing output of inside a cell.This not only rewrites the non-biological gain medium materials such as solids,semiconductors,etc.that are commonly used in conventional lasers,but also promotes the development of basic sciences such as photonics.It also makes great differences in the life sciences,especially in biosensing,optical detection and imaging.Because laser signals have the advantages of high detection sensitivity and easy resolution compared with conventional fluorescent signals.In this work,a new type of cell laser is taken as the starting point.At the same time,a relatively detailed investigation on the feasibility of the cavity laser design for the cell laser and the principle of cell laser are performed.The whispering gallery mode lasing and sensing signal based on micro-sphere resonator is theoretically and experimentally studied.And based on previous research,we also studied the different ways of achieving the cell laser and its applications.The major contents of this thesis include the following four parts:(1)Whispering gallery mode lasing emission based on a micro-sphere resonator was demonstrated experimentally and theoretically.Polystyrene-based micro-spheres were used as whispering-wall resonators.The diameter of the micro-sphere resonator was 15±0.5?m.At the same time,the micro-spheres were doped with Dragon Green dye to provide gain signals and the samples were fixed on two cover slips.Taking advantages of the principle of optical path design in fluorescence microscope,an optical system was set up on the optical platform.Spectroscopic detection and imaging detection of the sample micro-sphere can be achieved at the same time.The laser pump is at 473 nm,100 Hz repetition frequency,single pulse energy 10 ?J.Solid-state laser pumped a single dried Dragon Green micro-sphere and we can get a whispering mode laser output spectrum at 525-545 nm.At the same time,from this perspective of the basic theory of the whispering gallery mode,the modulation process of the optical signal is analyzed theoretically.(2)Laser sensing in the whispering gallery mode based on a micro-sphere resonator was demonstrated experimentally and theoretically.Firstly,based on the studying of laser emission experiments in the whispering gallery mode of the micro-sphere resonator,and on the basis of the principle of fluorescence energy resonance transfer,Dragon Green was selected as the donor,Rhodamine B as the acceptor.And secondly Rhodamine B dye aqueous solution with various concentration gradients was performed using Dragon Green's experiment in aqueous solution as reference standard.At last,we detected the signals of samples with different concentrations such as 0.005 mmol,0.001 mmol,0.005 mmol,0.01 mmol,0.05 mmol,0.1 mmol,0.5 mmol,and 1 mmol,respectively.The final analysis of the experimental results revealed that the center-to-peak spacing between the whispering gallery mode laser output spectrum and the Rhodamine B dye solution whispering gallery mode output spectrum are 0,28 nm,34nm,40 nm,42nm,44 nm and 48 nm,respectively,which realizes optical sensing detection for the concentration of Rhodamine B aqueous solution.It is due to the higher concentration of Rhodamine B dye solution within a certain concentration range,the higher the energy conversion efficiency between the donor and receptors,so that the spectral of the Dragon Green micro-sphere whispering mode laser emission spectrum blue shift,and the spectral of Rhodamine B dye solution whispering gallery mode red shift.(3)Whispering gallery mode cell laser based on a micro-sphere resonator was demonstrated experimentally and theoretically.Based on the study of whispering gallery mode laser emission experiments based on a micro-sphere resonator,human embryonic kidney 293 cells were used for the procession of endocytosis,and after 12 hours incubation with Dragon Green micro-spheres,the mixture of the Dragon Green micro-spheres and the cells was washed with PBS to remove the floating spheres.And then they were observed under a laser scanning confocal microscope to know if the embryonic kidney 293 cells endocytose Dragon Green micro-spheres successfully and have good fluorescence properties.Under 473 nm laser pumping,the 525-545 nm whispering gallery mode output light signal is preliminarily achieved,but it is still necessary to further confirm whether the micro-spheres the emitting signals are really inside the cells.(4)Cell laser based on Fabry-Perot Cavity was preliminary explored experimentally and theoretically.The Fabry-Perot cavity is another cavity type that realizes the laser output inside the cells.The pump source is independently designed and the wavelength is 532 nm laser.The repetition frequency is 1 KHz.The optical reflectance of the input mirror is 99.97%.The optical reflectivity of the output mirror is 96.29%.The rhodamine 6G dye solution was filled in a hollow core capillary.Laser emission was detected and the central wavelength was around 585 nm with dye solution.Fluorescence signal was detected with samples of human embryonic kidney cells transfected with tdTomato.And we also compared the the intensity of fluorescence signal before and after culture of 3D cells.