250 mJ, self-adaptive, diode-side-pumped Nd:YAG slab laser

Abstract

A scheme of self-adaptive, closed-loop, diode-side-pumped Nd:YAG slab laser was presented. As a result of four-wave mixing of standing waves intersecting at a small angle in a closed-loop cavity, the self-adaptive process of beam cleaning leading to fundamental mode operation despite severe asymmetry of the inversion profile and thermal-optical distortion was achieved. The output beam was extracted from the cavity as the first- order diffraction beam on the dynamic gain gratings created in an active medium. The near-diffraction-limited (parameter M(2)<1.4, divergence of 1 mrad) output beam of 250 mJ energy and the optical slope efficiency of 30% at a repetition rate of up to 25 Hz in a free-running regime were demonstrated.

Side-pumped neodymium laser with self-adaptive, nonreciprocal cavity

“…Additionally, it significantly degrades the spatial quality and decreases the overall performance of the laser system. There are several techniques, i.e., injection−seeding [1,2], grazing−incidence−angle [3,4] or self−adaptive resona− tors based on phase conjugation via gain saturation mecha− nism [5][6][7][8][9][10][11][12][13][14][15], that allow to generate near−diffraction−limited beam output in the presence of a high inhomogeneity of the gain spatial profile. In this paper we demonstrate the results of a self−adaptive Nd:YAG laser with intra−cavity amplifier with an open−loop, nonreciprocal cavity containing phase conjugate mirror.…”

Generation regimes of a pulsed Nd:YAG laser with transverse LED pumping and multiloop self-pumped phase-conjugate cavity

“…Recent interest in the lasers with four wave diffrac tion coupling in which the solid laser medium serves as both laser amplifier and element of optical coupling upon phase conjugation due to four wave interaction [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] has been driven by the progress in the technol ogy of multikilowatt LED pumping. The four wave interaction is based on the recording and reading of dynamic holograms (gain gratings in this work) that are recorded and erased upon development of laser generation and serve as a dynamic phase conjugate mirror.…”

“…The transverse pumping of such lasers by LED arrays with a total peak power of up to 9.5 kW on AE has been used in [14,15]. The pumping radiation is distributed over the AE length to provide a relatively high laser gain.…”

“…The pumping radiation is distributed over the AE length to provide a relatively high laser gain. Thus, two laser crystals [14] or one crystal [15] can be used in the phase conjugate laser. In this case, the output laser energies are 0.1 [14] and 0.25 J [15].…”

“…A decrease in the threshold and an increase in the efficiency of lasing can also be reached using the focusing of pumping radiation in the AE (an increase in the pump power density). A cylindrical lens with a focal length of 15 mm has been used in [15] for the focusing of radia tion of similar multikilowatt diode arrays to a spot with a size of 2.5 mm along the direction that is perpendic ular to the AE axis. Thus, the laser generation has been obtained in the cavity with the four wave interaction using only two LED arrays per AE (Nd:YAG crystal).…”