ИСТИНА

Effective, compact and robust picosecond lasers with single pulse energy of several millijoule level, controllable repetition rates within one kilohertz are claimed in satellite and lunar laser ranging, time-resolved laser spectroscopy, material processing, driving photoinjectors of mw-guns and electron accelerators. Advanced pulsed lasers systems generating ultrashort, mainly picosecond, pulses may use dynamical operation control schemes based on active and passive mode-locking, negative feedback and adjustable loss level in the oscillator cavity [1]. Main advantages of such lasers at the integration into complicated measuring systems and technological complexes can be linked to (i) the possibility of obtaining high energy and peak power levels just at the laser output at a sufficiently compact design, (ii) implementation simplicity of powerful amplifier stages, (iii) high output radiation stability and (iv) lower sensitivity to environmental operation conditions. In the present paper we demonstrate picosecond Nd:YAG laser with one stage amplifier operating with repetition rate up to 400 Hz and providing single pulse energy on the output up to 3 mJ. Both laser and amplifier use diode end-pumping by means fiber coupled laser diode arrays. Thermal lens in active elements of the oscillator tends to destroy operation at high repetition rates [2] and special efforts are paid to minimize the effect. Using Fabry-Perot etalons inside oscillator cavity allows varying output pulse width which can take several values between 25 and 280 ps. To describe evolution of time pulse profile a universal model specially aimed at numerical calculation of generation process in advanced pulse-periodic high-peak-power picosecond lasers [3] is used. The model describes pulse formation governed with active and passive mode locking, negative feedback, adjustable loss level in the resonator, and also taking into account the pulse profile modifying due to amplification. Further development of the model is presented. [1] M.V.Gorbunkov, A.V.Konyashkin, P.V.Kostryukov, V.B.Morozov, A.N.Olenin, V.A.Rusov, L.S.Telegin, V.G.Tunkin, Yu.V.Shabalin, D.V.Yakovlev. Quantum Electron., 35 (1), 2-6 (2005). [2] V.B.Morozov, A.N.Olenin, V.G.Tunkin, D.V.Yakovlev. Quantum Electron., 41 (6), 508–514 (2011). [3] N.G.Mikheev, V.B.Morozov, A.N.Olenin, D.V.Yakovlev. Proc .of SPIE, 9917, 99170A1-9 (2016).