Devices for Photonic and Quantum Technologies by Femtosecond (fs) LASER Micro-Structuring

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Name of the Speaker: MANO BALA SANKAR M (EE18S301)
Name of the Guide: Dr. Balaji Srinivasan
Date/Time: JULY 27th, 2022, 4:00 PM to 5:00 PM

Femtosecond (fs) laser micromachining is one of the most flexible manufacturing technologies to create micron sized features. Its ability to accurately and reproducibly create structures in a wide range of materials makes it an indispensable technology in a wide array of applications such as micro-cutting of cardiac stents, micro-scribing of silicon/thin film solar cells, micro-lithography of electronic chips, micro scribing/cutting of electrodes in flat panel displays, surface micro texturing of automotive engine parts, microfabrication of MEMS devices. The advantage of femtosecond pulses over the nanosecond (ns) or picosecond (ps) is their ability to deposit energy into a material in a very short time. It will remove or modify it before thermal processes originate. The ultrafast lasers vaporize matter without generating heat ("cold ablation"). The energy deposition process takes place quickly when compared to atomic relaxation procedures. In my research, I have examined the experimental ablation of a range of materials, including Si, SiO2, CoCr, PMMA, and YIG, which possess a wide value of strength (soft/hard). Most of these studies would benefit from an in-depth model of the Light Matter Interaction (LMI). To this end, a two Temperature Model (TTM) based on a set of coupled ordinary differential equations (ODE) which describe the time evolution of the temperatures of the electrons and lattice has been studied and implemented. It provides important information like ablation threshold, ablation depth, and optical propagation in the host medium. In this work, I have investigated the ablation of materials using COMSOL Multiphysics® version 5.6 for a time-dependent study on 2D geometry. We are extending such study to ultrafast laser-assisted ablation of soft, transparent, opaque, brittle, and hard materials including Si, PMMA, and YIG. The intended result is to make devices for photonic and quantum technology applications, as evident from the fabrication of waveguides and periodic gratings for Magnonics.