@MASTERSTHESIS{ 2020:1274857954,
 	title = {Optical Setup for Laser Microfabrication: development of photonic devices},
 	year = {2020},
 	url = "https://bdtd.unifal-mg.edu.br:8443/handle/tede/1736",
 	abstract = "Laser micromachining is a very useful technique that has been widely employed in a vast range of applications based on linear and nonlinear optics phenomena. In this context, the goal of this dissertation is to develop an optical micromachining system to make photonic devices on a reduced scale. For that, a Q-switch Nd:YAG pulsed laser with a temporal duration of 1.2 ns (nanosecond) operating at a low repetition rate (ranging from 10 to 2000 Hz) tuned at 532 nm (second-harmonic generation) was employed in this system. These features were assembled with a microscope mounted on a 3-D motor-driven stage, in which its movement is controlled by a homemade software that controls the stepper-motors over the XY-axis.  Also, the z-axis of controls the focus over the sample where the experiment will occur. Initially, gold and chitosan thin films were used to characterize the optical setup, which mistakes, dismisses, mismatches, and misalignments were mapped and solved. After some improvement in the optical setup along with the automation/controlling software, we performed a systematic study of micromachining of polymer films doped with azo-chromophores and perovskite quantum dots thin films. To better understand the laser setup, we have investigated the influence of laser energy, the translation speed, and the numerical aperture of microscope objective on the average width of the microstructure, which indeed, provided important data to support the good usage of such optical setup. Our results have shown that our micromachining setup is able to microstructure materials in two different regimes, that is, ablation and surface modification, for both polymer films containing azo-compounds and quantum dot films compound. These two regimes of micromachining were possible by controlling the incident energy from the laser path, the speed in which the specimen moves, and also by changing the microscope objectives. The objectives, however, have a lot of influence on the outcomes because its numerical aperture causes the light to be gathered wider or narrower. Such changes allow the same laser energy to cause different structures on the surfaces only by altering the objectives. To sum up these three features, we have achieved linewidths as narrow as 0.8 µm. Moreover, it is possible to microfabricate any shape of microstructure in our experimental setup due to the dedicated program development for this present work.",
 	publisher = {Universidade Federal de Alfenas},
 	scholl = {Programa de Pós-graduação em Física},
 	note = {Instituto de Ciência e Tecnologia}
}