Sunteti invitati sa participati la seminarului stiintific de miercuri, 06.04.2016, ora 10:00 din Sectia Laseri care va cuprinde prezentarea D-lui Simion Sandel cu titlul: „Real-time synchronization of ultrashort pulse laser beams, based on interferometric methods”
Abstract
The invention of ultra-short pulse lasers based on CPA (Chirp Pulse Amplification) technique, proposed in 1985, has enabled obtaining terawatt power laser beams, and pulse duration of tens of femtosecond. Currently there are several high power laser facilities with with between 1 and PW 2 PW, which reperezent now the technological limit for high power ultrashort pulse CPA lasers. This limit is due to nonlinear optical effects, the heat dissipation from the active medium and the size of optical components.
A solution to increase the laser power could be a parallel arrangement of two or more amplifiers that use a common laser oscillator followed by combining the generated laser beams. The difficulty of synchronizing high power laser beams is caused by unsteady operating regime caused by small repetition frequency (0.01 Hz – 10 Hz) and optical path fluctuations with tens of meters length, making each laser pulse emission to be considered as unique event.
The paper proposes a method for optical path correction in the interval between two successive emissions of ultrashort laser pulses, which allows real time correlation for two multi-pass Ti:Sapphire amplifiers. The paper also describes the design and development for a system which controls the optical path using the proposed method. The measurement of the optical path difference between the two amplifiers is based on interferometric method, in this respect the system comprising an interferometric sensor which includes original solutions that enable high-speed measurement (~ 10 mS) resolution measurement of ~ 20 nm and retrieving the information about optical path difference that is lost during amplification laser when the interference is perturbed.
The experimental model has managed to maintain fluctuation for the optical path difference between wo multi-pass Ti: Sapphire amplifiers below 100 nm, this value allowing the laser beams to be coherently combined (with a calculated efficiency of 40%) or incoherently combined.
