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A study on Laguerre-Gaussian (LG) modes selection in cw and pulsed Nd:YAG or Yb:YAG ceramic lasers pumped by diodes or an external laser source was carried out. Methods of scalar and vector LG modes selection from low to high orders, involving shaping of the pump profile, usage of intra-cavity lenses, uniaxial crystals and polarization selective mirrors, are considered. CCD camera images of beam profiles of hollow scalar LGpm modes (p -radial, m -azimuth indices) of record high-orders and Bessel-like multi-ring modes with highly directional propagation properties are presented. CW and pulsed ceramic lasers with radially or azimuthally polarized LG vector modes of low and high orders are also demonstrated. Applications of the developed laser schemes and LG beams are discussed. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The transient interaction between a refraction index grating and light beams during simultaneous writing and thermal fixing of a photorefractive hologram is investigated. With a diffusion- and photovoltaic-dominated carrier transport mechanism and carrier thermal activation (temperature dependent) considered in Fe:LiNbO3 crystal, from the standpoint of field–material coupling, the theoretical thermal fixing time and the space-charge field buildup, spatial distribution, and temperature dependence are given numerically by combining the band transport model with mobile ions with the coupled-wave equation. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 372–376, 1999.

A simulated annealing algorithm is adopted to design multiple-pump Raman fiber amplifiers. A demonstration of the optical fiber Raman amplifier using five laser diode pumps with different wavelengths and powers is presented. The automatic configuration of the pump gives an amplification bandwidth of more than 50 nm (64 signal channels), with a fluctuation of less than 1.8 dB. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 434–436, 2001.