"3D ultrafast laser nanolithography of optical crystals: Avenue to next generation solid-state photonics?" by Airan Rodenas

Seminar by Airan Rodenas, Professor, Leap Lab, Universidad de la Laguna, Espagne

Abstract

Nanolithography is at the heart of current microelectronics and photonics technologies and therefore of our lives. Developing materials and patterning them at the sub-micron level, ideally with precision on the 10nm scale or higher, is the fundamental process which sustains our current communication technologies, and probably holds a key on our chances of tackling the big challenges of our civilization: the climate emergency and the population growth (expected 10 billion by 2050). Our work focuses on a new class of nanolithography [1] which makes it possible to nanostructure crystals in three dimensions and with nanoscale precision. Our focus is on the potential of the technique for the development of future extreme-environment and real world functional devices, investigating the potential development of various new types of fundamental optical and photonic building blocks, such as diffractive elements, photonic crystal structures, and new laser cavity sources embedded inside solid-state laser crystals (garnets and sapphire), extremely important for the worldwide optics industry and also well known for their large resistance to extreme environments. In this seminar I will introduce the technique's current characteristics and limitations, and I will present some recent findings on how controlling in both time and space the localized interaction of fs-pulses with the crystals, produces a palette of final material states with well differentiated properties, which we characterize by means of SEM morphology as well as by wet-chemical etching reactivity. The implication of these results in strictly applied terms resides in the knowledge of how to control 3D lithographic parameters, such as the nanopore's cross-section and aspect ratios, the wet-chemical etching rates, and the achievable fabrication times; Lastly, I will comment on our current projects on the development of novel photonic elements and devices.