Study On Micro-Optical Elements And Systems Based On Composite 3D Printing Technology

Micro-optical elements have great potential applications in imaging,communications,and medicine because of their high design freedom,small size,and light weight.The innovative development of three-dimensional(3D)printing technology(such as extrusion,inkjet,stereolithography,digital light processing and two-photon polymerization)and the novel design of micro-optics and systems provide the basis for iterative updates of microoptics and systems.Although great progress has been made in relevant research,there are still some key issues and challenges: A single traditional 3D printing technology cannot efficiently process 3D structures across scales and precisions;the design and processing of micro-optical components and systems cannot meet the needs of high performance and multi-function.For the contradiction between the processing efficiency and processing accuracy of the current single 3D printing technology,a compound 3D printing technology combining femtosecond laser direct writing(Fs DLW)and digital micromirror device(DMD)microstereolithography(DMDMSL)is proposed,which realizes the high-efficiency processing of cross-scale and cross-precision three-dimensional structures by 3D printing technology.In addition,we have designed a variety of high-performance and multi-functional microoptical elements and systems,including microfluidic diffractive elements,refractive/diffractive hybrid lenses,double-sided micro-optical systems and double-sided optofluidic systems.And these are processed with high efficiency based on composite printing technology.The main research contents are as follows:(1)Research on compound processing technology combining femtosecond laser direct writing and DMD micro-stereolithography.For the problem of the efficiency and accuracy of a single 3D printing technology cannot be balanced,we propose a new composite 3D printing technology strategy combining Fs DLW and DMDMSL.In this composite technology,through image processing and mapping relationship establishment,the lateral alignment of the processing process is realized;Through pattern focusing and vertical height calibration,vertical alignment during processing is achieved;The effective data splitting method ensures the highest efficiency and reasonable allocation of machining accuracy.The processing resolutions of Fs DLW and DMDMSL in this composite system are 400 nm and 1.3 μm,respectively,and the horizontal and vertical alignment accuracy of the system reaches 2 μm and 3 μm,respectively.The processing resolutions of Fs DLW and DMDMSL are 400 nm and 1.3 μm,respectively,and the horizontal and vertical alignment accuracy of the system reaches 2 μm and 3 μm,respectively.The results of these structures such as lateral composite,horizontal vertical composite,and wrapped composite indicate that the technology is capable of 3D printing across scales and precisions.And compared with only Fs DLW,the machining time can be shortened by up to 0.65%.Based on the original general technology,Fs DLW-DMDMSL is expected to expand to more micro and nano fields.(2)Research on high performance broadband diffractive optical elements.For the problems of large dispersion and low diffraction efficiency in wide band of traditional diffractive elements,we proposed a novel microfluidic diffractive element(MFDOE).MFDOE combines the concepts of microfluidics,multi-layer diffractive elements and harmonic diffractive elements.The high diffraction efficiency of wide band is achieved by using the matching of microfluidic liquid materials to reduce the additional phase of multilayer diffraction elements;The ideal phase distribution is proportional to the wavelength by the quantization method of harmonic diffraction element,and the chromatic aberration is effectively eliminated.Based on the structural characteristics of low-precision large-size frame structure and high-precision serrated relief of MFDOE,we use Fs DLWDMDMSL for high-efficiency processing.A high-quality MFDOE that is highly consistent with the theoretical design is obtained.MFDOE has a diffraction efficiency of up to 90% in the visible light band(400-700 nm),and achieves achromatic properties for both 469 nm(±20 nm)and 625 nm(±20 nm)light.MFDOE solves the problem of low performance of traditional diffractive elements and enriches the types and functions of existing diffractive elements.Furthermore,we design a refractive/diffractive hybrid achromatic lens and process it using the Fs DLW-DMDMSL technique.The refractive/diffractive hybrid lens has good dual-wavelength achromatic properties in a wide wavelength band,and high-quality imaging performance with a resolution of 80 lp/mm.(3)Research on double-sided micro-optical system and optofluidic system.For the problems of poor structural stability and limited application of single-sided microsystems,we designed a double-side microoptics imaging system and an optical flow control system.The double-sided micro-optical imaging system has the characteristics of high surface precision,good structure,and performance stability.Its imaging resolution of 80 lp/mm enables good imaging of tiny particles.The double-sided optofluidic system has good screening and collection capabilities for mixed particles with diameters of 14 μm and 15 μm,and performs real-time imaging and monitoring of the collection,realizing a multifunctional microfluidic chip.The development of these bifacial systems may aid in the development of diversity in the fields of micro-optics,microbiology,and medicine.