We demonstrated a broadband Nd: glass laser amplifier with controllable gain bandwidth in experiment, which is expected to be used in high energy low coherent laser amplifier system. A birefringent crystal for spectral filtering in regenerative laser amplifier was designed and proposed, and the parameters of birefringent crystal was optimized in simulation. The birefringent crystals with different bandwidths were designed by this method. The laser amplification output with different gain bandwidths of 6~10 nm was realized, which was also verified by experiments. This broadband Nd: glass laser amplifier is expected to be used in large scale broadband laser amplification system, and provides important technical support for a new type of broadband tunable nanosecond high-power laser facility.
Broadband low-coherence light has been applied in many fields such as optical imaging, atmospheric optical communication and laser inertial confinement fusion(ICF). It’s meaningful to investigate the temporal shaping technology of broadband low-coherence light. We propose and experimentally demonstrate a scheme of achieving all-optical arbitrary temporal shaping of broadband low-coherence light based on saturable absorption effect. Compared to traditional temporal shaping schemes such as electro-optic modulation(EOM) shaping or acousto-optic modulation(AOM) shaping, the modulation on the shaped pulse profile is much smaller, reduced from 14% (by acousto-optic modulator) to 3%(close to the ASE noise). Furthermore, we explore the evolution of shaped pulse contrast (intensity ratio between front edge and end edge) with the pump energy and contrast changing. The contrast of shaped pulse can be adjusted from 1:1.32 to 1:1.02 when pump contrast is 1:2, and from 1:2.25 to 1:1.90 when pump contrast is 1:3. And the maximum contrast of shaped pulse can reach 1:17 within the measurement accuracy. By changing the energy and contrast of pump, the contrast of the shaped pulse can be controlled flexibly. It’s useful to achieve all-optical arbitrary temporal shaping and pre-compensation during pulse amplification.
With the development of fiber technologies, fiber lasers are able to deliver very high power beams and high energy pulses which can be used not only in scientific researches but industrial fields (laser marking, welding,…). The key of high power fiber laser is fiber amplifier. In this paper, we present a two-level master-oscillator power amplifier system at 1053 nm based on Yb-doped photonic crystal fibers. The system is used in the front-end of high power laser facility for the amplification of nano-second pulses to meet the high-level requirements. Thanks to the high gain of the system which is over 50 dB, the pulse of more than 0.89 mJ energy with the nearly diffraction-limited beam quality has been obtained.
A fiber-based，high precision long-term stable time synchronization system for multi-channel laser pulses is presented，using fiber pulse stacker combined with high-speed optical-electrical conversion and electronics processing technology. This scheme is used to synchronize two individual lasers including a mode-lock laser and a time shaping pulse laser system. The relative timing jitter between two laser pulses achieved with this system is 970 fs (rms) in five minutes and 3.5 ps (rms) in five hours. The synchronization system is low cost and can work at over several tens of MHz repetition rate.
An all-fiber multi-pass phase modulator for chirped pulse amplification centered at 1053nm is demonstrated. An optical pulse with a 3-dB bandwidth of 2.23nm centered at 1053 nm is obtained based on the system. And spectrum with negative dispersion is obtain by an all-fiber architecture which can be used for ultrashort laser source in ps.
A pulse stretcher using chirped fiber Bragg grating is demonstrated. Pulses from a 1053nm mode-locked fiber seed
oscillator are multi-stretched by a Linear chirped grating set in a fiber regenerative amplifier structure. We have the pulse
stretched from 23.6ps to 378ps after it transmits 3 loops in the stretcher. The major factors which affect the stretched pulse
shape are discussed.
In high-power laser system, in order to extend the components' service life and reduce the operation costs, more
attentions should be pay at the research for damages ablation at multi-layer optical components and other high load
optical components. 240ps, 35ps, 6ps 1053nm laser pulses has been used to investigate damage ablation and damage
resistant experiments at 0° high reflection films. By comparing the damage morphology and damage resistant threshold
of the ablation pits at different pulses width, it was superior to use ultra-short pulse to repair multi-layers optical
components. It was found that the shorter pulse width has been used, the higher the damage resistant threshold and the
lower the laser modulation. Furthermore, the finite-difference time-domain method was used to simulate the
electric-field intensification within the large size damage region of multilayer films.