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We have demonstrated a diode-side-pumped Q-switched Nd:YAG laser operating at 1319 nm with a saturable absorber of graphene oxide fabricated by the vertical evaporation method. The 1319 nm Q-switched laser pulses were realized with average output power of 820 mW, pulse width of 2 μs and repetition rate of 35 kHz. The pulse energy and peak power were 23.4 μJ and 11.7 W, respectively when the optical pump power was 232 W. The experimental results indicate that graphene oxide is an effective saturable absorber for Q-switched lasers.

We demonstrated a high power laser at 532 nm by frequency-doubling of an acousto-optically Q-switched and side-pumped Nd:YAG laser at 1064 nm using a compact linear cavity. The average output power of the pulsed fundamental laser at 1064 nm was as high as 299 W. The laser employed two acousto-optic Q-switches placed orthogonally with each other to improve the hold-off capacity. Through intracavity frequency doubling with a type II non-critically phase-matched LBO crystal, a 165 W average power of the frequency-doubled output at 532 nm was generated with a repetition rate of 20 kHz and pulse width of 160 ns, which corresponds to a pulse energy of 8.25 mJ and a peak power of 51.6 kW, respectively. The output power of the green laser was very stable and the stability at various output powers was measured. The RMS instability was ±1.4% when the output power of 532 nm was 135 W. After coupling the 165 W output power at 532 nm into an 800 μm fiber, the final output from the optical fiber was 149 W with a coupling efficiency of 90.3%.

Monolayer MoS2 film on quartz was fabricated by a home-made three-temperature zone chemical vapor deposition method. The photo, AFM image, Raman spectroscopy and HRTEM image showed that high quality as-grown MoS2 film completely covered the whole quartz substrate of a few cm2. A Nd:YVO4 laser with mode-locking operation was obtained by using the monolayer MoS2 on quartz as the saturable absorber (SA). To the best of our knowledge, this is the first report on large-area growth of high quality monolayer MoS2 film on transparent quartz substrate, and the first time that the CVD MoS2 SA was used in mode-locked solid state lasers. Because of the large area, high transmission, low non-saturable loss and high optical damage threshold of this material, it is very suitable for application in mode-locked solid state lasers.

During the process of laser propagation in free space, energy attenuation is brought by atmospheric medium. One of the major problems about laser propagation is that atmospheric component does not remain constant within the whole altitude band. So working out the relatively accurate attenuation coefficient is a research interest of many researches for several years. On this basis of analysis of the atmospheric component distributing characteristic, simple and practical simulate approach was given to meet the needs of laser rangefinder. The main work is the research on 1.06μm YAG laser transmission characteristics in the atmosphere, and the atmosphere loss of the mathematical model is investigated. The paper discussed the influence of atmospheric attenuation on ranging ability of laser rangefinder and analyzed the atmospheric attenuation theoretical. It showed that when the attenuation coefficient γ increases the detectable distance decreases rapidly. In the condition of three transmission modes, which are ground-to-ground mode, ground-to-air mode and air-to-air mode, the relationships between atmospheric transmittance and different visibility, different zenith angle were analyzed. Minimal detectable power of laser rangefinder represents ranging ability in above-mentioned three different modes was formulated with atmospheric transmittance. Based on the results, we can adjust the experimental parameters and achieve more desirable results. It has positive influence for the design of laser rangefinder.

In this paper, we investigated the characteristic of radar target, the spherical and the pyramidal missile warheads, and compared the RCS and performance of the targets with and without the cover of the plasma metamaterials. Numerical simulation is obtained by the numerical calculation Finite-difference time-domain method (FDTD). The parameters of plasmonic structures as a metamaterial cloak was designed and optimized. The relationship between the parameters of the cloak and the corresponding electromagnetic characteristic of the target are analyzed by the simulation and discussion in broadband radar signals. After optimization, the plasma cover could attenuate 40 dBsm of the radar cross section (RCS) of the targets maximally. The result shows that the anomalous phenomenon of cloaking and stealth effects induced by plasma materials for the radar target, which might have potential application of military affairs.

We demonstrated a Q-switched Nd:LuVO 4 laser with fundamental mode at 1064 nm using BaB2O4 electro-optic Q-switching. High-efficiency operation of Q-switched laser with dynamic to static ratio of 91.4% was realized. When the absorbed pump power was 6.59 W, the maximum average output power of 2.88 W was achieved with a repetition rate of 50 kHz. The optical conversion efficiency and slope efficiency were 43.7% and 55.5%, respectively. The minimum pulse width of 17.8 ns was achieved. Meanwhile, the pulse energy and peak power were 57.6 μ J and 3.2 kW, respectively. To the best of our knowledge, this study is the first to demonstrate about the electro-optically Q-switched laser in Nd:LuVO 4 crystal.

A Nd:GdVO4 crystal is end-pumped by a fiber-coupled laser diode(FCLD), and high power of single-frequency laser output is achieved. The four-mirror bow-tie ring cavity with a Faraday rotator and a half wave plate is applied to eliminate the spatial hole-burning effect. A solid etalon is inserted into the cavity to obtain single-frequency1063 nm output of the narrow line width. The maximum output is7.57 W and the optical-optical conversion efficiency is41.8% with18.10 W of the incident power.