Shuanggen Zhang

Formation of epitaxial Tl2Ba2CaCu2O8 thin films at low temperature in pure argon

Mirror‐like Tl2Ba2CaCu2O8 thin films have been reproducibly prepared on (001)LaAlO3 substrates by dc magnetron sputtering using 80% argon and 20% oxygen and post‐annealing at temperatures of 720–760 °C in 1 atm pure argon. X‐ray diffraction patterns of θ‐2θ scans, φ scans, and Read camera photographs prove that the thin films are strongly textured with the c‐axis perpendicular to the substrate surfaces and epitaxially grown to the substrate with Tl2Ba2CaCu2O8(100) parallel to the LaAlO3(100). The zero resistance temperatures are in the range of 105.2–108.6 K for the 0.2–1.0‐μm‐thick films. The critical current density of 5.3×106 A/cm2 at 77 K has been obtained at zero magnetic field for a 0.4‐μm‐thick film.

Second harmonic generation of periodically poled potassium titanyl phosphate waveguide using femtosecond laser pulses

The authors have presented in this paper the fabrication and characterization of double line written type waveguides in c-cut periodically poled potassium titanyl phosphate crystals. The waveguides were fabricated by using a femtosecond laser, and were utilized for second harmonic generation at 1064 nm. Our experiments have shown that single mode propagation was observed at optimal waveguide width of 14.5 microm. And a conversion efficiency of 39.6% can be achieved.

Fabrication and characterization of periodically poled lithium niobate waveguide using femtosecond laser pulses

We present in this letter the fabrication and characterization of thermally stable type II waveguides in Z-cut periodically poled lithium niobate crystals. The waveguides were fabricated by using a femtosecond laser and were utilized for second harmonic generation. Our experiments have shown that a quasiphase matching wavelength of 1548.2nm, a tuning bandwidth of 2nm, and a tuning temperature range of 150.4±1.6°C can be achieved.

Second harmonic generation in periodically poled lithium niobate waveguide using femtosecond laser pulses

We present in this paper the fabrication and characterization of thermally stable double line waveguides in Z-cut periodically poled Lithium Niobate crystals. The waveguides were fabricated by using a femto-second laser, and utilized for second-harmonic generation. Our experiments have shown that a quasi-phase matching wavelength of 1548.2 nm, a tuning bandwidth of 2 nm, and a tuning temperature range of 150.4±1.6°C can be achieved.

Simulative analysis of periodically poled waveguide second-harmonic-generation device in Z-cut MgO:LiNbO3

The numerical study of annealed proton exchanged (APE) waveguide in Z-cut periodically poled LiNbO3 is presented using finite element method (FEM), compared with beam propagation method (BPM). Also given the analysis of the effects of different annealed time and annealed temperature on modes distribution.

Femtosecond second-harmonic generation in periodically poled lithium niobate waveguides written by femtosecond laser pulses

Second harmonic generation of femtosecond pulses in PPLN waveguide written by femtosecond laser pulses was described both theoretically and experimentally. An average power conversion efficiency of 21.5% was obtained.

Output characteristics of Q-switched fiber laser based on electro-optic ceramics

In this paper, a novel Q-switched fiber laser made up of OptoCeramic electrooptic ceramics is reported. The ring laser is composed with an electrooptic ceramics modulator as Q-switched, a highly Yb-doped fiber as the gain medium, and pumped by a semiconductor laser of 976 nm wavelength. Q-switched is realized from modulating the loss, controlled by the material refractive index, which is changed with the voltage of OptoCeramic element. The laser system generates pulses about 100ns, with the repetition rate continuously adjusted from 3kHz to more than 40 kHz.

The self similar pulse formation study of mode-locked fibre lasers

Self similar mode locked fiber laser is studied based on a numerical model. By introducing a dimensionless factor k to characterize the pulse, the self similar pulse formation and its temporal and spectral changes are investigated throughout the cavity. The influences of all the elements inside the cavity on the pulse formation are also studied.