General Seminar
Miercuri, 3 Aprilie 2024, ora 14:00
CETAL, Seminar room
Title: „Polarization encoded filters for suppressing gain-narrowing and red-shifting effects in Ti:sapphire amplifiers”
Prezintă: Razvan Dabu, National Institute for Laser, Plasma and Radiation Physics
Abstract: Gain narrowing and red shifting effects in Ti:sapphire chirped pulse amplifiers can result in significant spectral distortion and correspondingly lengthening of the re-compressed amplified pulse duration. Suppression of the gain-narrowing and red-shifting effects is of great significance for the development of high-power Ti:sapphire femtosecond laser systems. The spectra shaping in polarization encoded filters (PEFs) based on optical rotatory dispersion (ORD) in quartz crystals represents a flexible method for the gain-narrowing suppression in high gain amplifiers and the red-shifting suppression in high energy amplifiers. The filtering characteristics of a PEF which consists in a half-wave plate, a quarter-wave plate, a quartz crystal, and a thin film polarizer are theoretically analyzed by the Jones calculus. The alignment procedures of the waveplates axes for the generation of the desired spectrum shape of broadband chirped laser pulses are described. An experiment of laser pulses spectral broadening at the output of the Ti:sapphire regenerative amplifier from the Front-End of a high power femtosecond laser system is proposed.
