基于ZnO可饱和吸收体的超快激光器

Ultrafast Laser Based on ZnO Saturable Absorber

ZnO是一种优异的可饱和吸收体(SA),然而它在近红外波段的光吸收性能较弱,限制了其在超快光子学领域的进一步应用。首先采用水浴法制备了ZnO微球粉末,旋涂到金镜衬底上制备成ZnO-SA,再利用磁控溅射法及热退火在ZnO-SA表面修饰了金纳米颗粒,制备了一种新型的金核壳结构的ZnO-SA。由于金纳米颗粒的表面等离子体吸收效应,将ZnO-SA的调制深度提升至4.07%,非饱和损耗降低至24%。使用这种新型的ZnO-SA成功地提升了调Q激光器的输出特性,同时也构建了稳定的波长为1.55μm环形腔掺铒光纤锁模激光器,最大平均输出功率为2.67 mW,重复频率为3.53 MHz。研究结果表明,这种具有金纳米颗粒修饰的ZnO-SA在制备高性能锁模激光器方面具有巨大的应用潜力。

ZnO is a kind of saturable absorber(SA)material with excellent performance.However,the weak optical absorption performance in the near infrared band limits it further application in the field of ultrafast photonics.Firstly,ZnO microsphere powder was prepared by using water bath method,and then the powder was spin-coated onto gold mirror substrate to prepare ZnO-SA.Then,gold nanoparticles were modified on the surface of ZnO-SA by magnetron sputtering method and thermal annealing to prepare a new type of ZnO-SA with gold core-shell structure.The modulation depth of ZnO-SA was increased to 4.07%and the nonsaturable loss was reduced to 24%due to the surface plasmon absorption effect of gold nanoparticles.Using this new ZnO-SA,output characteristics of Q-switched laser were improved successfully,and a stable ring cavity erbium-doped fiber mode-locked laser at a wavelength of 1.55μm was constructed.The maximum average output power of 2.67 mW and the repetition frequency of 3.53 MHz were achieved.These results show that the ZnO-SA modified with gold nanoparticles has great application potential in the fabrication of high-performance mode-locked lasers.