Calcium-niobium-gallium garnets with Nd: a new active medium for lasers with ultrashort pulse duration

Autor: Manfred Helbig, Sergey N. Ushakov, Alexander A. Sobol, Alexander Ya. Karasik, Tasoltan T. Basiev, Yu. K. Voron'ko, N A Es'kov, Vladimir V. Fedorov, Vyacheslav V Osiko
Rok vydání: 1992
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
Popis: Results of spectroscopic and radiation investigations of disordered calcium-niobium-gallium garnets (CNGG) with wide inhomogeneously broadened lines in absorption and luminescence of Nd3+ are presented. A method of a selective and frequency tuned laser excitation at T equals 77 K provided discovery of four groups of optical centers and development of Stark multiplet 4F3/1 and 4I9/2 levels schemes for these centers. Laser excitation at the 4I11/2 yields 4F3/2 transition at T equals 300 K during time resolved luminescence spectra recording at the same transition resulted in discovery of an inhomogeneous character of amplification spectrum broadening as well as in estimation of spectral energy migration among the centers. This time it was found to be longer than the 4F3/2 level lifetime (150 microsecond(s) ec). Results of the investigation of free-generation and passive mode-locking regimes in lasers based on disordered garnets with neodymium are presented. It is shown that energy parameters of the lasers based on CNGG are higher than those of glass lasers. In the passive mode-locked regime pulses are generated with (lambda) equals 1.06 micrometers and duration time 5 - 7 psec. The pulses have positive linear frequency chirp and spectrum broadening up to 60 cm-1. Compression of the chirped pulses in an external compressor provides transfer to femtosecond time scale.
Databáze: OpenAIRE