Generation of radially and azimuthally polarized beams in Yb: YAG laser with intra-cavity lens and birefringent crystal (original) (raw)
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Optics Letters, 2010
We report maintenance of perfect radial-polarization purity in high-power, cw pump chambers using strengthened, polycrystalline Nd:YAG laser rods. Although the cubic symmetry of single-crystal rods caused threefold symmetric birefringence due to shear stresses at the ends of the pumped zone, polycrystalline rods macroscopically behaved as isotropic material and enabled polarization preservation. Elimination of this source of depolarization prevents the major source of bifocusing aberrations in a chain of amplifiers.
Generation of radial polarization in Nd:YAG and CO2 lasers and its applications
2005
Radially polarized radiation shows some very interesting properties and has therefore gained interest in recent years. An overview of the advantages and the various applications where radially polarized modes are beneficial is given. In addition the different known methods to generate radial polarization are reviewed. In our work we developed a method to generate radially polarized laser beams by means of a polarization selective resonant grating mirror. The undesired polarization is coupled to a mode of the dielectric multilayer of the resonator end mirror and experiences severe losses while the radial polarization is not affected and oscillates in the laser resonator. Fundamental and higher-order radially polarized modes of high polarization purity and powers of more than 100W have been demonstrated.
Radially polarized Yb:YAG thin-disc laser
2008
Beams with radial polarization have attracted an increasing interest during the past few years because of their attractive properties. An overview of the different intra- or extra-cavity techniques to generate such beams is given in the present paper. The design, fabrication and characterization of a multilayer polarizing grating mirror developed for an Yb:YAG thin-disc laser resonator are reported. The potential of the proposed solution is discussed together with the first demonstration of a radially polarized Yb:YAG thin-disc laser.
High-power radially polarized Yb:YAG thin-disk laser with high efficiency
Optics Express, 2011
Radially polarized beams with an output power of 275 W, M 2 = 2.3 and an efficiency of about 52.5% were generated from an Yb:YAG thindisk laser. An intra-cavity circular resonant waveguide grating was used as a polarization selective mirror inside the laser cavity. We report on the design and the fabrication using a scanning beam interference lithography system and discuss the calculated and measured performances of the presented polarizing grating mirrors.
High-power dual-rod Yb:YAG laser
Optics Letters, 2000
We describe a diode-pumped Yb : YAG laser that produces 1080 W of power cw with 27.5% optical optical efficiency and 532 W Q-switched with M 2 2.2 and 17% optical -optical efficiency. The laser uses two composite Yb : YAG rods separated by a 90 ± quartz rotator for bifocusing compensation. A microlensed diode array end pumps each rod, using a hollow lens duct for pump delivery. By changing resonator parameters we can adjust the fundamental mode size and the output beam quality. Using a f lattened Gaussian intensity prof ile to calculate the mode-f ill eff iciency and clipping losses, we compare experimental data with modeled output power versus beam quality.
Birefringence-induced bifocusing for selection of radially or azimuthally polarized laser modes
Applied Optics, 2007
We develop round-trip matrix diagonalization method for quantitative description of selection of radially-or azimuthally-polarized beams by birefringenceinduced bi-focusing in a simple laser resonator. We employ different focusing between radially and tangentially polarized light in thermally stressed laser rods to obtain low-loss stable oscillation in radially-polarized LG (0,1)* mode. We derive free-space propagator for the radially-and azimuthally-polarized LG(0,1)* modes and explain basic principles of mode selection by use of the round-trip matrix diagonalization method. Within this method, we calculate round-trip diffraction losses and the intensity distributions for the lowest-loss transverse modes. We show that for the considered laser configuration, the round-trip loss obtained for the radially-polarized LG (0,1)* mode, is significantly smaller than that of the azimuthally-polarized mode. Our experimental results, obtained with diode sidepumped Nd:YAG rod in flat-convex resonator, confirm the theoretical predictions. Pure radially-polarized LG (0,1)* beam with M 2 =2.5 and output power of tens watt was achieved.
Unidirectional Single-Mode Nd:YAG Laser with a Planar Semimonolithic Ring Cavity
Applied Optics, 1999
Unidirectional single-mode operation of a diode-pumped Nd:YAG laser with a planar semimonolithic ring cavity has been demonstrated at 1064 nm. The semimonolithic cavity consists of a laser active medium placed in a magnetic field, a crystal quartz plate, and an output coupling mirror, which form an optical diode by acting as a Faraday rotator, a reciprocal polarization rotator, and a partial polarizer, respectively. A single-mode output power of 155 mW and a slope efficiency of 17% were obtained with a 1.2-W diode laser at 809 nm. A laser linewidth of less than 100 kHz is inferred from a beat note frequency spectrum between two identical laser systems and continuous tuning to greater than 2 GHz was observed.