Femtosecond laser micro/nano processing: from fundamental to applications

Able to precisely control and manipulate materials' states at micro/nano-scale level, femtosecond (fs) laser micro/nano processing technology has undergone tremendous development over the past three decades. Free-forming three-dimensional (3D) microscale functional devices and inducing fascinating and unique physical or chemical phenomena have granted this technology powerful versatility that no other technology can match. As this technology advances rapidly in various fields of application, some key challenges have emerged and remain to be urgently addressed. This review firstly introduces the fundamental principles for understanding how fs laser pulses interact with materials and the associated unique phenomena in section 2. Then micro/nano-fabrication in transparent materials by fs laser processing is presented in section 3. Thereafter, several high efficiency/throughput fabrication methods as well as pulse-shaping techniques are listed in sections 4 and 5 reviews four-dimensional (4D) and nanoscale printing realized by fs laser processing technology. Special attention is paid to the heterogeneous integration (HI) of functional materials enabled by fs laser processing in section 6. Several intriguing examples of 3D functional micro-devices created by fs laser-based manufacturing methods such as microfluidics, lab-on-chip, micro-optics, micro-mechanics, micro-electronics, micro-bots and micro-biodevices are reviewed in section 7. Finally, a summary of the review and a perspective are proposed to explore the challenges and future opportunities for further betterment of fs laser micro/nano processing technology.