Novel Laser And Biological Detection Based On Optofluidic Systems

Nowadays,the opticfluidic technology has attracted a great attention,because it has the ability to combine the optical technology with microfluid,and it makes the all-powerful optical system possible.Optofluidics is widely used in both micro and macro scales,and has a very high impact in the fields of photonics,chemical synthesis and biosensing.However,at present,the optical fluid technology is still in the early stage of research,and few optofluidic devices have been formally built to commercial applications.Some basic problems in the microfluidic system still brought troubles to the application of the optiofluid chip.In this paper,we studied the optofluidic microcavity,dye laser,flow cell analysis and biological trace detection.The research content can be divided into the following four parts:we present a novel optofluidic waveguide with a submillimeter microcavity.At first,we analysis the quality factor?Q value?and the spontaneous emission coupling ratio??value?of this new resonator thretically,and discuss the physical mechanism of ultrahigh order modes?UOMs?phenomenon in detail.Simulation and experimental results show that the hollow-core metal-cladding waveguide?HCMW?has the advantages of high Q value and high?value.HCMW can significantly increase spontaneous radiation and reduce the laser emission threshold.Subsequently,we do experiments to verify the above results.We prepared solution of R6G and a continuous laser was used to pump the HCMW.The experimental results and throretical results show that the HCMW is an excellent optical resonator.Then,we prepared a methylene blue dye solution with a concentration of 2.579*10^-13 mol/ml to serve as gain media for the first time.The HCMW was used as the resonant cavity and a continuous semiconductor laser with the wavelength of 473 nm was used as a pump laser.In the experiment,methylene blue dye solution was injected into the HCMW by syringe pump.When the incident light is coupled into the guiding layer,we can observe two laser beams with wavelength of 708.5 nm and 723.1 nm,respectively.The threshold of the two laser beams was 2.1 mW/cm².This novel laser dye proves that many fluorescent dyes have the potential to be used as gain media for laser emission.This novel dye laser is small in size,low in price,and has application value in environmental science,biomedicine and chemical engineering.The future application of HCMW will open up a new broad prospect for optofluidics and integrated optics.We designed a flow cytometer based on fiber Bragg grating based Fabry-Perot?FBG-FP?cavity.We simulated the transmission spectrum of the cavity containing three different particles,respectively,and found that the resonance peak of the transmission spectrum would change with the particle size.After that,we made a microfluidic chip with simple devices,which can detect the particles by label free method.The experimental results show that the particle size is related to the shift of the resonance peak,which fit well with the simulation results.This flow cytometry for particle detection provides a simple and feasible method to improve the detection efficiency.Its advantages of recycling can significantly reduce the waste of resources,so it is expected to be applied in the field of biomedicine,chemistry,environmental science and biological sensing.We analyzed the biological trace by optical method.Human blood attached to cover glass and plastic bag is irradiated respectively by femtosecond laser ultraviolet band.hen,the blood of the human body was tested by using the mid-infrared spectrometer and the Raman spectrometer.It was found that the approximate storage time of human blood could be defined by using the ratio change of the mid-infrared spectrum,while the Raman spectrum could distinguish the blood from other biological traces.Therefore,the Raman spectrum and mid-infrared spectrum are reliable in biological detection.Then we fabricated a simple Surface Ehanced Raman scattering substrate.Polydimethylsiloxane?PDMS?has advantages of flexible and deformable.We coated the stretching PDMS chips with a layer of silver film,and a layer of one-dimensional silver structure was made on the surface after the PDMS chips were rebound.We use Raman spectroscopy to detect the prepared PDMS substrate containing R6G solution.The experimental results confirme that this PDMS substrate coated with one-dimensional silver structure has good Raman enhancement effect.