No Arabic abstract
Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 {mu}m and 3.3-3.8 {mu}m regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 {mu}m. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved: the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.
We report the first mode-locked fiber laser to operate in the femtosecond regime well beyond 3 {mu}m. The laser uses dual-wavelength pumping and non-linear polarisation rotation to produce 3.5 {mu}m wavelength pulses with minimum duration of 580 fs at a repetition rate of 68 MHz. The pulse energy is 3.2 nJ, corresponding to a peak power of 5.5 kW.
We have developed a Watt-level random laser at 532 nm. The laser is based on a 1064 nm random distributed ytterbium-gain assisted fiber laser seed with a 0.35 nm line-width 900mW polarized output power. A study for the optimal length of the random distributed mirror was carried out. An ytterbium-doped fiber master oscillator power amplifier architecture is used to amplify the random seeder laser without additional spectral broadening up to 20 W. By using a periodically poled lithium niobate (PPLN) crystal in a single pass configuration we generate in excess of 1 W random laser at 532 nm by second harmonic generation with an efficiency of 9 %. The green random laser exhibits an instability <1 %, optical signal to noise ratio >70 dB, 0.1 nm linewidth and excellent beam quality.
We have developed a Watt-level single-frequency tunable fiber laser in the 915-937 nm spectral window. The laser is based on a neodymium-doped fiber master oscillator power amplifier architecture, with two amplification stages using a 20 mW extended cavity diode laser as seed. The system output power is higher than 2 W from 921 to 933 nm, with a stability better than 1.4 percent and a low relative intensity noise.
In this paper we consider mid-infrared Raman lasers based on gas-filled hollow-core silica fibers and provide theoretical and experimental analysis of factors that limit the efficiency and output power of these lasers. As a result, we realized an efficient ns-pulsed 4.42 {mu}m Raman laser based on an 1H2-filled revolver silica fiber. Quantum efficiency as high as 36 % is achieved, and output average power as high as 250 mW is demonstrated. The possibilities of further improving the laser efficiency are discussed.
Black phosphorus, a newly emerged two-dimensional material, has attracted wide attention as novel photonic material. Here, multi-layer black phosphorus is successfully fabricated by liquid phase exfoliation method. By employing black phosphorus as saturable absorber, we demonstrate a passively Q-switched Er-doped ZBLAN fiber laser at the wavelength of 2.8 {mu}m. The modulation depth and saturation fluence of the black phosphorus saturable absorber are measured to be 15% and 9 {mu}J/cm2, respectively. The Q-switched fiber laser delivers a maximum average power of 485 mW with corresponding pulse energy of 7.7 {mu}J and pulse width of 1.18 {mu}s at repetition rate of 63 kHz. To the best of our knowledge, this is the first time to demonstrate that black phosphorus can realize Q-switching of 2.8-{mu}m fiber laser. Our research results show that black phosphorus is a promising saturable absorber for mid-infrared pulsed lasers.