An extension of the characteristic angle method to the easy-plane spin-32 ferromagnet
Abstract The characteristic angle (CA) method [J. Phys. A 27 (1994) 5599], developed previously for the easy-plane spin-1 magnetic systems, has been successfully extended to the spin - 3 2 case. A compact form of the CA spin - 3 2 operator transformation is given. Then the ground state energy, the magnon dispersion relation and the spontaneous magnetization are discussed for an easy-plane spin - 3 2 ferromagnet by using the CA method. A comparison with the old theoretical methods is made.
Quantum fluctuations in easy-plane spin-one ferromagnet
The magnetic properties of easy‐plane spin‐one Heisenberg ferromagnet, H=D∑i(Six)2 −J∑(i,j)Si⋅Sj−h∑iSiz, are investigated using the linked cluster series expansion. The results of the linked cluster series expansion method cover the whole range of temperatures, both magnetically ordered and disordered phases. The order parameter is included in correlations of spin fluctuation and solved self‐consistently to high orders. The magnetization as a function of temperature for a given value of easy‐plane anisotropy is shown. The observed values of magnetization from the linked cluster series expansion are appreciably depressed from their mean‐field approximation values due to the quantum and thermal fluctuations. The effects of the quantum fluctuation on the magnetic ordering in three‐dimensional (3D) systems are discussed.
Coherent pulsed injection seeding of two gain-switched semiconductor lasers
High-power, narrow-spectrum, short pulses at a wavelength near 830 nm are needed for optical logic applications. The authors report the generation of two coherent trains of pulses by pulsed injection seeding of two gain-switched semiconductor lasers with one mode-locked master oscillator. The available power was doubled and both lasers emit in nearly identical spectral lines. Short pulses (30-50 ps) are generated at a repetition rate of 1.9 GHz. The spectrum is reduced to a single mode cluster and shows a 1.7 AA wide chirp suitable for pulse compression. The peak power is 0.1 W for each pulse train. The capability of this technique for coherent power combining is demonstrated.<<ETX>>