A V Fedin

Self-Q-switching at phase conjugation in active media

Self-Q-switching of the Nd:crystal (Nd:YAG, Nd:GGG) and the Nd:glass multiloop lasers (phosphorus GLS-22) with self- pumped phase conjugation (SPC) in active media is investigated experimentally and theoretically. A possibility to realize single-mode single-frequent self-Q-switched laser radiation as repetitive giant pulse trains of 50 W average and 100 kW peak power with no Q-switcher is shown. Temporal dynamics of self-Q-switching and the mechanism of its occurrence on gain gratings are investigated with a help of the rate equations.

Study of lasing on the 4F3/2 → 4I13/2 secondary transition of Nd3+ ions in a phase-conjugate Nd3+ : YAG laser

Lasing at a wavelength of 1.34 µm on the 4F3/2 → 4I13/2 secondary transition of Nd3+ ions in a phase-conjugate (PC) Nd3+ : YAG laser under four-wave mixing in a laser medium is theoretically and experimentally investigated. The influence of the amplified spontaneous emission at a wavelength λ = 1.064 µm on the parameters of phase-conjugate generation of the Nd3+ : YAG laser at λ = 1.34 µm under passive Q switching by a V3+ : YAG crystal using two-, three-, and four-loop open cavity schemes is analysed by mathematical simulation. It is shown that there is an optimal initial transmission of a passive Q switch (PQS), the value of which decreases with increasing number of cavity feedback loops. The generation in the Nd3+ : YAG laser at λ = 1.34 µm with an open PC multiloop cavity is experimentally obtained and studied for the first time. Emission in the form of a train of seven pulses with a total energy of 0.25 J and individual pulse energy and duration of 36 mJ and 150 ns, respectively, is obtained with an initial PQS transmission of 74 %. The angular divergence of the laser beam is found to be 0.7 mrad at quality factors and .

Single-mode Nd lasers with adaptive cavity and self-phase-conjugation

Self-pumped phase-conjugate multiloop Nd:YAG, Nd:YAP, and Nd:Glass lasers are investigated and developed. The parametric feedback is realized by dynamic holographic gratings in active and passive LiF:F2- Q-switcher medium. High power and spatial laser characteristics are obtained: Nd:YAG laser - - 114 W average power at 0.5 mrad beam divergence; Nd:YAP laser -- 51 W average power at 1.2 mrad beam divergence; Nd:Glass laser --18 J in pulse train at 1 mrad beam divergence.

High-effective laser hole drilling in metals and alloys

Optimization and adaptation of 15 - 200 micrometer small dia and 2 - 20 mm deep holes drilling with the hole shape variation less than plus or minus 10% are discussed. For this purpose, the single-frequency laser system with self-phase- conjugation and passive Q-switching by a scanned gradiently colored LiF:F2- crystal is used. Steels, hard- facing and aluminum alloys, and ceramics are used as samples.