Study On Functionalized Photonic Micro/nano-devices By Femtosecond Laser Processing

People have begun to pay attention to the development of photonic chips as along with electronic devices continue to shrink,the density of integrated circuits continues to increase,and problems such as quantum tunneling and heat dissipation have become more prominent.The photonic chips,which are still in the experimental stage,only need the old micro-scale process to achieve the calculate ability that greatly exceeds the existing semiconductor chips.With the increase of chip density,performance can grow substantially,and even have the opportunity to completely rewrite the limitations of Moore's Law.At present,the mainstream of integrated photonic chips is still a silicon optical chip based on integrated electronic chip.Since the beginning of the 21 st century,enterprises and academic institutions led by Intel and IBM have taken the lead in developing silicon optical signal transmission technology.It is expected to replace the data circuits between chips with optical channels.At the same time,when silicon optical chips are being chased by people,the unique advantages of other non-semiconductor material systems such as glass and polymer on photonic chips have gradually attracted the attention of researchers.However,the fabrication process of photonic chips based on non-semiconductor materials is still dominated by photolithography,which greatly limits the stereoscopic construction and three-dimensional functions of photonic chips.Therefore,this paper proposes micro-nano/integrated devices based on polymer system using femtosecond laser two-photon polymerization,which can prepare threedimensional devices that be used in integrate photonic chips.Specifically,it is mainly divided into the following aspects:?.Preparation protein-based of micro-nano devices by femtosecond laser: Utilizing the advantages of no mask,non-contact,low thermal damage,etc.,Direct writing of protein gel-based micro/nano waveguides and three-dimensional inverse field lens groups.The pH sensing of the protein-based micro/nano-waveguide and the seconddegree tuning of the focal plane of the lens group are achieved by the equilibrium swelling of the protein molecular group.?.Direct writing protein-hydrogel-based unequal-arm Mach-Zehnder interferometer: Taking advantage of the characteristics of high-precision point scanning of femtosecond lasers,by controlling the flexible control of processing power,two interferometer arms have the same geometry but with different refractive indices and the stimuli-responsive shrinkage/expansion characteristics.A complete optical switching operation is achieved by increasing the salt concentration from 0 to 8 x 10-3 mol/L.?.Two-photon polymerization to prepare on-chip true three-dimensional laser source: Further develop the ability of true three-dimensional processing of femtosecond lasers,combined with the easy doping of polymer materials,the preparation of the active microsphere resonator on the chip is realized.At the same time,due to the advantages of femtosecond lasers,different sizes of microspheres can be easily formed.We have found that when the diameter of the microspheres is reduced,the lasing light changes from a multimode output to a single mode output,and the lasing wavelength is correspondingly blue shifted.At the same time,due to the participation of organic dyes,the spectrum of the microsphere laser will also move regularly when the temperature changes.?.Laser nano-printing of on-chip polarization controller: Fully tap the power of femtosecond laser for true 3D machining and high-precision scanning,realizing polymer-based on-chip wave plate,showing polarization rotator for both communication band and visible band,and both have a relatively high polarization conversion efficiency.Further,a polarization router with four waveguides of different twist angles is demonstrated,and the polarization conversion efficiency of the four channels is greater than 85%.In summary,in this work,the femtosecond laser direct writing process with true three-dimensional processing capability enables traditional lithography-based devices to be free on the three-dimensional scale.It provides a solution for the threedimensional arrangement of photonic chips and multi-dimensional operation of photons.First,a femtosecond laser processing system is used to obtain a high-precision,highquality polymer-based micro/nano photonic device.Take advantage of femtosecond laser processing for high-precision point scanning and the unique advantages of polymer materials to achieve unique features of the devices.Further,in-depth mining of the true three-dimensional processing power of femtosecond laser processing,combined with material properties,to realize the true three-dimensional integrate devices,and the solutions and designs that are difficult to implement by other processing methods.