2微米波段的Tm, Ho:LuScO飞秒激光陶瓷的局域配位结构调控与性能研究

Femtosecond laser at 2 microns possesses the merits of safety to eye, high water absorption rate, high atmospheric transmittance, etc, and are regarded to have significant applications in the areas like photomedicine, optical communication, molecular spectroscopy and so on. However, the 2 μm ultrafast laser development has lagged compared with the 1 μm waveband. The most popular femtosecond lasers operating around 2 µm are based on the solid laser medium doped with trivalent Tm3+ and Ho3+ ions using passively mode-locked method. As such laser materials are extremely difficult to prepare, it already became affects one of the laser development key questions. To solve this problem, it is proposed in this program that the localized coordination structure of the novel Tm, Ho co-doped (LuxSc1-x)2O3 ceramics can be precisely regulated. The research will illuminate the essences and principles of “spectrum tailoring”, study the mechanism of the mixed ceramics sintering kinetics, and develop new methods appropriate for the optical quality improvement. Ultimately, mid-IR femtosecond laser with the bandwidth of 2 µm will be realized using the developed new materials, laying the foundation of the ultrashort pulse technology at middle to far infrared wavelength and promote the domestic basic and applied research related to this topic.

2微米波段飞秒激光具有人眼安全、水吸收率高和大气透过率高等优点，在光医学、光通信、分子光谱等领域意义重大，但是目前其技术发展相对于1微米飞秒激光明显滞后。实现2μm飞秒激光，采用掺杂Tm3+/Ho3+固体激光介质的锁模技术是最有效技术途径之一，而此类激光介质材料制备难度较高，已经成为制约发展的关键瓶颈问题之一。针对上述问题，本项目以Tm3+/Ho3+共掺杂的新型(LuxSc1-x)2O3透明混晶陶瓷开展研究，通过局域配位结构的精确调控，探索阐明实现“光谱剪裁”的本质规律，研究混晶固溶体陶瓷的烧结动力学机制，探索品质因数的提升方法，实现基于新型材料的超快2微米飞秒激光输出，为进一步实现中远红外超短激光技术进步奠定基础，促进我国在该领域的基础科研及应用开展。

采用掺Tm3+和Ho3+的LuScO陶瓷激光器是实现2 μm飞秒激光的最有效途径之一，其在光医学、光通信、分子光谱、材料加工和军事等领域具有重要的应用价值。为了解决Tm3+和Ho3+掺杂的新型LuScO透明混晶陶瓷制备难题，实现基于新型材料的超快2微米飞秒激光输出，为进一步实现中远红外超短激光技术进步奠定基础，本项目对Tm3+和Ho3+掺杂LuScO陶瓷开展研究。. 项目通过基于微区控制的并行反应沉淀法，研究分析了实验过程中陈化时间、喷雾速度、分散剂添加量、煅烧温度及掺杂等对纳米粉体的化学成分、微观结构等的影响行为与机制，优化试验参数，研制出高纯度、细粒径且窄分布的高烧结活性粉体。. 通过对烧结制度、x值和掺杂的调控研究，认识了Tm, Ho:LuScO陶瓷的烧结特性，研究明确了不同真空烧结温度和保温时间对于陶瓷微观结构和致密度的影响行为，在无烧结助剂的情况下实现了陶瓷的高质量烧结，并最终获得了透过率高达81.22%@2090 nm的高透明陶瓷样品。. 同时，通过对局域配位结构的调控研究，发现随着x值的增加，晶格畸变程度和离子扩散特性等随之改变，陶瓷的烧结致密化特征和透明度先提升后下降。另一方面，对比研究发现混晶比例的变化会影响对陶瓷的微观结构和光谱性能，随着x值在一定范围内的增加，晶格畸变和微观结构无序的程度会同时变大，导致样品的平均晶粒尺寸减小，致密度有所提高，而发射光谱也会出现一定的红移和展宽现象。这些结论有助于指导局域配位结构的精确调控和材料设计，探索实现“光谱剪裁”的本质规律。. 通过本项目工作，掌握了LuScO陶瓷的品质因数的提升方法，实现了新型材料的58fs的超快2微米飞秒激光输出新记录，有助于实现中远红外超短激光技术的进一步发展。