Hybrid femtosecond laser three-dimensional micro-and nanoprocessing: a review

The extremely high peak intensity associated with ultrashort pulse width of femtosecond (fs) lasers enabled inducing nonlinear multiphoton absorption in materials that are transparent to the laser wavelength. More importantly, focusing the fs laser beam inside the transparent materials confined the nonlinear interaction to within the focal volume only, realizing three-dimensional (3D) micro/nanofabrication. This 3D capability offers three different processing schemes for use in fabrication: undeformative, subtractive, and additive. Furthermore, a hybrid approach of different schemes can create much more complex 3D structures and thereby promises to enhance the functionality of the structures created. Thus, hybrid fs laser 3D microprocessing opens a new door for material processing. This paper comprehensively reviews different types of hybrid fs laser 3D micro/nanoprocessing for diverse applications including fabrication of functional micro/nanodevices.