Narrow Results

We have proposed a model to incorporate the energy transfer up-conversion (ETU) effect on the performance of actively LD-pumped Q-switched kilo-watt lasers. Under the optimal output transmission condition, the optimal ratio of the pump mode to the laser mode are found to be within 0.85 and 1.1 to minimize the influence of the ETU on the output power, so the maximum pulse energy and the peak power can be obtained.

Q-switched fiber lasers are very attractive sources in many applications such as in military affairs, surgical operation, laser machining, laser marking, nonlinear frequency conversion, range finding, remote sensing and optical time domain reflectometer. Our goal is to improve the pulse energy of a Q-switched fiber laser. In this paper, certain feasible methods to improve the pulse energy are presented, with their theoretical basis clarified, which may be helpful for the design of kindred Q-switched fiber lasers.

Q-switched fiber lasers are very attractive sources in many applications such as military affairs, surgical operation, laser machining, laser marking, nonlinear frequency conversion, range finding, remote sensing and optical time domain reflectometer. To improve the peak power of Q-switched fiber laser is what we pursue, and to know the factors that influence the peak power is what we should make clear first. In this paper, certain essential factors that influence the peak power are presented, with their theoretical basis clarified, which may be helpful to the design of the kindred Q-switched fiber lasers.

In this work, MoSe₂ film is synthesized by the chemical vapor deposition method. Saturable absorber (SA) is assembled with the tapered fiber and MoSe₂ films. Q-switched operation is achieved with the MoSe₂-based SA. The experimental result reveals that the MoSe₂-based SA has excellent saturable absorption characteristic with 23.41% modulation depth. When the pump power is greater than 289.2mW, Q-switched all-fiber lasing action is demonstrated. The repetition rate of the Q-switched pulses varies from 185.6 to 252.8kHz. The shortest pulse duration is 801.9ns, and the largest output energy is 69.3nJ. Results indicate that MoSe₂ films can provide new opportunities for large-modulation-depth optical modulators in ultrafast photonics.

Transition metal oxides (TMOs) are distinguished by their thermal and chemical stability as well as excellent optical, electrical, and magnetic properties. Moreover, the 3$d$-orbital electrons of the transition metal ions in TMOs have a strong $d-d$ Coulomb interaction, enabling them to exhibit a variety of unusual physical phenomena, dramatically different from conventional metals and semiconductors. Additionally, TMOs possess excellent nonlinear optical properties, such as third-order nonlinear response and saturation absorption, which make them broadly applicable for ultrafast photonics devices. Herein, a review is presented of the nonlinear optical properties of typical TMOs, as well as their employment as saturable absorbers in near-infrared pulsed fiber lasers in recent years. Finally, some challenges and promising prospects for nonlinear ultrafast photonic devices based on TMOs are discussed.