Pulsed laser deposition of thin film magneto-optic materials and lasing waveguides
Pulsed laser deposition of thin film magneto-optic materials and lasing waveguides
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薄膜磁光材料和激光波导的脉冲激光沉积
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发表时间：
2014
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通讯作者：
A. Sposito
中科院分区：
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作者：
A. Sposito
本论文的目的是研究和改善通过薄膜生长技术沉积的光学材料的性能。脉冲激光沉积是一种相对快速、廉价和通用的沉积方法，它使用激光烧蚀靶材并在衬底上转移材料。材料包括钛掺杂蓝宝石(钛：蓝宝石或钛：氧化铝)，用于制造紧凑、低损耗、高效率和高功率的波导激光器，也可以在超快高重复频率脉冲模式下工作；磁光石榴石，如YIG，Y3Fe5O12，用于制造高性能的低损耗磁光和微波器件。优化了钛宝石和YIG薄膜的沉积条件，并利用多激光多靶点PLD系统(MULTI-PLD)通过共烧蚀两个不同的靶材(如YIG和Y2O或Fe2O或Bi2O或CeO2)来调节YIG薄膜的成分。制作了钛宝石光波导，并测量了其光学性能(如传输损耗和激光特性)。研究了成分变化对磁光石榴石薄膜结构、光学和磁学性能的影响，论证了多重PLD方法的可行性，该方法能够通过烧蚀具有不同烧蚀速率的前驱体靶(Y_2O_3或Fe_2O_3)以及在不同衬底上沉积材料，特别是Y铝石榴石(Y_3Al_5O_12或Y_3Al_5O_(12))和蓝宝石(Al_2O_3)来制备YIG和YFeO_3等复合晶态氧化物材料。一些YIG薄膜也被用来展示晶体材料的激光诱导前向转移(LIFT)以及PLD生长的YIG薄膜在新型超材料微波器件中的应用。
The aim of this thesis was to study and improve the properties of optical materials deposited by the film growth technique called Pulsed Laser Deposition (PLD), a relatively fast, inexpensive and versatile deposition method using a laser to ablate a target and transfer material on top of a substrate. The materials of interest were titanium-doped sapphire (Ti:sapphire or Ti:Al2O3) for fabrication of compact, low-loss, high-efficiency and high-power waveguide lasers, which could be also operated in ultra-fast highrepetition-rate pulsed mode, and magneto-optic garnets, e.g. yttrium iron garnet (YIG, Y3Fe5O12), for fabrication of low-loss magneto-optic and microwave devices with high performance. Deposition conditions were optimised for Ti:sapphire and YIG film growth and a multilaser multi-target PLD system (multi-PLD) was used to tune the composition of YIG film by co-ablation of two different targets (e.g. YIG and Y2O3 or Fe2O3 or Bi2O3 or CeO2). Ti:sapphire waveguides were fabricated and their optical performances (e.g. transmission losses and lasing characteristics) measured. A study of the effect of compositional variation on structural, optical and magnetic properties of magneto optic garnet films was carried out and it demonstrated the feasibility of the multi-PLD approach, which was shown to be capable to grow complex crystalline oxide materials, such as YIG and yttrium ferrite (YFeO3), from ablation of their precursor targets (Y2O3 or Fe2O3) with different ablation rates and deposition of material on different substrates and, in particular, yttrium aluminium garnet (YAG or Y3Al5O12) and sapphire (Al2O3). Some YIG films were also used to demonstrate Laser-Induced Forward Transfer (LIFT) of crystalline materials and the applicability of PLD-grown YIG films in novel meta-material microwave devices.