Generation, optimization, and application of ultrashort femtosecond pulse in mode-locked fiber lasers

The photoluminescence parameters of Nd3+-doped Sr0.95Y0.05F2.05 crystal, which are a function of Nd3+ concentrations, were investigated. Abnormally, the peak emission cross section increased linearly with the lifetime. The quantum efficiency, peak emission cross section and lifetime were significantly improved from 26%, 2.8 × 10−20cm2 and 190μs to 90%, 5.4 × 10−20cm2 and 370μs, respectively. The results suggest that Y3+ ions worked as local lattice structure regulators and barrier layers besides the well known buffer ions.

Modulated photoluminescence parameters of neodymium in Sr_095Y_005F_205 laser crystal

The codopant assisted tunable photoluminescence and highly efficient CW lasers in Nd3+:SrF2 crystal

In this paper, we present an enhanced high-power extrinsic diode side-pumped solid-state laser (DPSSL) model to accurately predict the dynamic operations and pump distribution under different practical conditions. We introduce a new implementation technique for the proposed model that provides a compelling incentive for the performance assessment and enhancement of high-power diode side-pumped Nd:YAG lasers using cooperative agents and by relying on the MATLAB, GLAD, and Zemax ray tracing software packages. A large-signal laser model that includes thermal effects and a modified laser gain formulation and incorporates the geometrical pump distribution for three radially arranged arrays of laser diodes is presented. The design of a customized prototype diode side-pumped high-power laser head fabricated for the purpose of testing is discussed. A detailed comparative experimental and simulation study of the dynamic operation and the beam characteristics that are used to verify the accuracy of the proposed model for analyzing the performance of high-power DPSSLs under different conditions are discussed. The simulated and measured results of power, pump distribution, beam shape, and slope efficiency are shown under different conditions and for a specific case, where the targeted output power is 140 W, while the input pumping power is 400 W. The 95% output coupler reflectivity showed good agreement with the slope efficiency, which is approximately 35%; this assures the robustness of the proposed model to accurately predict the design parameters of practical, high-power DPSSLs.

Robust modeling and performance analysis of high-power diode side-pumped solid-state laser systems.

Recent studies have shown that interplanetary missions may be made possible using inflatable solar sails that employ solar-flux power, providing thrust for spacecraft while reducing onboard fuel requirements. These sails require a large surface area (i.e., 100 m in diameter) to capture enough solar flux for spacecraft navigation. In this paper, a novel communication antenna concept is proposed for future solar-sail missions, taking advantage of the large sail surface area via application of Fresnel-zone (FZ) antennas. This study focuses on utilizing a design/analysis methodology using physical optics (PO) and method of moments (MoM) for Fresnel-type antennas applicable to the solar-sail missions. Extensive parametric studies of Fresnel-zone antenna radiation characteristics have been performed, and the analytical methodologies were verified using a series of measurements. Fresnel-zone antenna gain is studied under different antenna configurations. Furthermore, a Fresnel-zone antenna under surface deformation is investigated to characterize Fresnel-zone antenna performance in the reflective mode. In addition, a new bandwidth-enhancement technique is introduced for Fresnel-zone antennas, to accommodate the dual-band operation ( X band uplink and downlink) of the antenna for the deep space network (DSN).

A novel antenna concept for future solar sails: application of Fresnel antennas

The phase Fresnel zone plate, whose diffraction efficiency is up 97%, has been made. Because of the advantages of thinner thickness, lighter weight and design flexibility, the phase Fresnel zone plate has been considered for use as a MM-wave antenna so as to increase the diffraction efficiency. However, zone plates with only four phase steps are generally made up to now, so the diffraction efficiency is only about 80%, and the highest gain is no more than 35 dB. To overcome this weakness, a new kind of Fresnel zone plate antenna with a continuous phase structure is designed, and the authors call it a diffraction antenna.

Design of MM-wave Fresnel zone plate reflector antenna with continuous phase structure

Laser diode end-pumped accousto-optical Q-switched Nd:YVO4 laser with high power and high slope efficiency

对Nd，Y：CaF2晶体作为激光放大器的增益介质进行了报道.研制了一台采用激光二极管面阵五向水平侧面抽运5 mm70 mm Nd，Y：CaF2的激光放大器，对其进行了实验研究.测量了Nd，Y：CaF2晶体的吸收谱、发射谱、以及放大器的荧光分布.在相同的抽运功率下，测量了Nd，Y：CaF2与Nd：Glass放大器分别工作在10 Hz和1 Hz重复频率时的小信号增益，在抽运功率为9.63 kW时，Nd，Y：CaF2放大器的小信号增益达6.12，为Nd：Glass的1.5倍.与Nd：Glass相比，Nd，Y：CaF2晶体的重复工作频率不仅大大提高，而且增益性能也更强.测量了种子光和经Nd，Y：CaF2放大器后的光谱，能量放大前后光谱几乎无变化.

Fan Zhongwei

Papers

Design of MM-wave Fresnel zone plate reflector antenna with continuous phase structure

Laser diode end-pumped accousto-optical Q-switched Nd:YVO4 laser with high power and high slope efficiency

Experimental study of diode-pumped Nd, Y:CaF2 amplifier for inertial confinement fusion laser driver

High repetition rate and high beam quality joule level Nd: YAG nanosecond laser for Thomson scattering diagnosis

Monitoring and Compensation of Large-Size Flat-Top Laser Beam