Temperature control system of Titanium-Saphire laser cavity in femto-second regime using Peltier modules

• Grant number: 20/04657-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2020
• End date: July 31, 2021
• Field of knowledge: Engineering - Electrical Engineering - Industrial Electronics, Electronic Systems and Controls
• Principal Investigator: Jarbas Caiado de Castro Neto
• Grantee: Iago Carvalho de Almeida
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

This project deals with the development of the air cooling system of the Titanium-Saphire laser cavity for femto-second regime operation through a pumping laser DPSS Verdi/Coherent 532 nm, allowing laser marking on metallic surfaces and creating periodic nanostructures which have many applications in the industry and in medicine. The cooling system is based on using a Peltier thermoelectric module, being the temperature control of the module designed through the step response of the thermal system operating in open loop. The step response allows to estimate a first order transfer function through the MATLAB toolbox ident, which, using the method of controller tuning and design rltool, can then be used to obtain the controller transfer function to be used in closed loop through a feedback of the output signal. Through digital control techniques, the obtained controller will be transferred from the Laplace's complex frequency domain to the discrete Z domain, allowing its description in terms of a difference equation that can be implemented in a micro-controller in order to realize the control logic. After finishing the controller project, tests will be carried on through simulations in the Simulink environment in order to verify the obtained dynamics and, later on, experimental tests will be realized to validate the results. When experimental results coherent with the simulated ones are obtained, the system will be tested with the incidence of the laser in the Titanium-Saphire crystal, being expected that any temperature fluctuations will be compensated through the control system of the Peltier module, allowing the crystal to operate under the desired reference temperature. The success of this project will allow the substitution of water cooling systems by air cooling systems, making the equipment more compact and easing its mobility, for example, inside industries.