Femtosecond laser writing of integrated optical structures in glasses

In this paper, we describe how among the many variables in fs laser waveguide writing, the repetition rate has the most important role as it influences the heat accumulation between laser pulses, which determines the regime of modification and the resulting morphological change. Chapter Contents: • 12.1 Introduction • 12.2 Fundamentals of buried medication of glasses with focused femtosecond laser pulses • 12.2.1 Nonlinear absorption • 12.2.2 Relaxation and material modification • 12.2.2.1 Pulse energy • 12.2.2.2 Repetition rate • 12.2.2.3 Focusing • 12.3 Femtosecond laser waveguide writing in glasses • 12.3.1 Low repetition rate fabrication • 12.3.1.1 Fused silica glass • 12.3.1.2 Silicate and phosphate glasses • 12.3.1.3 Chalcogenide glasses • 12.3.2 High repetition rate fabrication • 12.3.2.1 Fused silica glass • 12.3.2.2 Silicate and phosphate glasses • 12.3.2.3 Chalcogenide glasses • 12.3.3 Ion migration in high repetition rate modification of multicomponent glasses • 12.3.4 Comparison of low and high repetition rate processing • 12.4 Applications • 12.4.1 Photonic devices • 12.4.1.1 Bragg grating waveguides for telecom/sensing • 12.4.1.2 Active devices • 12.4.1.3 3D architectures for astronomy • 12.4.1.4 Directional couplers for quantum information • 12.4.2 Microfluidic devices • 12.4.2.1 Hybrid FLICE for particle filter • 12.4.2.2 Liquid-liquid dynamic interfaces • 12.4.2.3 Refractive index sensor • 12.5 Conclusions • References.