Femtosecond micro/nano-machining of dielectric materials for the fabrication of three-dimensional photonic devices

This work explores the potential of femtosecond lasers as a tool for the fabrication of 3D photonic devices in dielectric materials. Femtosecond pulses can cause permanent damage in dielectric materials through laser induced breakdown (LIB). The characteristics of the damage depend on the pulse and material parameters. The nonlinear characteristic of the LIB allows the damage to be produced inside the materials without affecting the surface. We take advantage of this phenomenon to fabricate 3D photonic devices inside glass and pattern monolayer self-assembled silica microspheres using different pulse parameters and materials.; Femtosecond machining is attractive for its ability to realize 3D fabrication. However, most experiments need an amplifier system, which is expensive and limits the application of femtosecond machining. We demonstrate femtosecond machining in borosilicate glass with record low pulse energy (3.5 nJ) from a Ti:Sapphire oscillator of high repetition rate, which could lead to broad usage of femtosecond machining.; We then propose and fabricate the first reported computer generated volume hologram (CGVH) at 633 nm in borosilicate glass with an amplifier. A CGVH is a 3D refractive index modulation, which the 3D fabrication ability of femtosecond machining is most suitable to realize. We also make use of femtosecond laser induced birefringence to realize a polarization selective computer generated hologram (PSCGH) at 514 nm in fused silica glass. Current methods for the fabrication of PSCGHs rely on natural birefringent crystals and/or lithography, which are not suitable for the fabrication of 3D photonic devices. Our work in CGVH and PSCGH may lead to the realization of more efficient 3D integrated optics with additional functionalities.; Photonic crystals (PhCs) are appealing for their ability to control light and are finding application in fields such as efficient energy conversion and semiconductor lasers. However, current methods for fabricating defects in 3D PhCs have limitations in the cost, speed or scale. We apply femtosecond machining to selectively remove microspheres from self-assembled arrays. This technique serves as a first step towards the creation of defects within 3D PhCs on a large scale.