Design And Fabrication Of Micro-Optical Components Based On Femtosecond Laser Direct Writing

With the rapid development of modern science and technology,the miniaturization,modular integration,functional diversification,stable performance and low power consumption have become the advance direction of all instruments and functional devices.In this way,the micro optical system is relatively intact in theory,and the micro optical components show the excellent and unique performance relatived to the traditional macroscopic optical elements.The development of micro optics not only extends the scope of the research in the field of optics,but also makes the miniaturization and integration of the instrument possible.At present,main microsodium processing technologies are optical exposure,electron beam lithography,nanoimprint lithography,etching and laser processing technology.Femtosecond laser direct writing technology,with its beyond the diffraction limit of the processing accuracy and penetration of the surface of the true three-dimensional processing capabilities and other micro processing technology to form a distinct complementary technology.Femtosecond laser direct writing technique has been used in the fabrication of micro optical components for more than 20 years.In this thesis,based on the femtosecond laser processing technology,a variety of functional micro optical components are designed and fabricated.The main research contents include:(1)Refractive micro optical elements: The design and fabrication of asymmetrical beam shaping micro lens for edge emitting semiconductor laser.The fast/slow axis divergence angle of the laser is reduced from 60 degree and 9 degree to 6.9 mrad and 32.3mrad,respectively.The variable focus microlens array is fabricated.The unique optical properties of the array are expected to play an important role in the field of filed curvature correction,real-time display and 3D parallel processing.(2)Diffractive micro optical elements: Based on laser induced refractive index change,we prepared buried type spiral zone plate in lithium niobate.The device maintains stable optical properties in a complex external environment.Production of large size aplanat sapphire zone plate.Quantitative characterization of spherical aberration of the device characteristics and compared with the same size of spherical mirror and aspheric mirror.The refractive / diffractive hybrid structure is fabricated to produce the optical vortex field,which greatly simplifies the complexity of the optical vortex generation system.(3)Microcavity lasers: A suspended directional single wavelength laser is fabricated.This work presents a simple method to improve the performance of microcavity laser by adding a simple circular hole.In this paper,based on the femtosecond laser direct writing technique,oriented on the fabrication of functional micro optical devices,the design,fabrication and characterization of micro optical devices are studied in detail.From fragile organics to hard optical materials,from surface to internal induced refractive index change,from qualitative to quantitative characterization,we have done a lot of technical accumulation and theoretical support for the oriented commercialization on the fabrication of micro optical elements by femtosecond laser direct writing technology.