基于低温稀土离子掺杂晶体的波长可调谐激光稳频技术研究

Tunable lasers are highly flexible and widely applied because their tunable wavelength which can satisfy different kinds of demands in application. However, frequency stabilization and narrow linewidth of tunable laser is difficult to achieve because of the lack of references which are available for multiple wavelengths. Laser frequency stabilization locked on cryogenic rare-earth-ions doped crystals has a lower temperature coefficient (20Hz/mK), and also has a lower acceleration sensitivity which is an order of magnitude lower than the best Fabry-Perot cavity (7×10-12/g). Furthermore, the continuously tunable frequency locking position over the whole inhomogeneous broadening of rare-earth-ions and the widely variable central wavelengths in different rare-earth-ions and hosts provide locking references for wide range tunable lasers. Therefore, rare-earth-ions doped crystals at cryogenic temperature will be feasible for the frequency stabilization of wide range wavelength continuously tunable lasers. In our project, frequency stabilization of 790-795nm tunable lasers reference based on Tm3+-ions doped crystals at cryogenic temperature will be studied first. With this technological groundwork, frequency stabilization and narrow linewidth will be achieved for more tunable lasers in wider wavelength range.

可调谐激光源，因其波长可在一定范围内调谐变化，能够适应不同的应用要求，因此灵活性强、适用广泛。但是，窄线宽、连续可调谐的超稳频激光源因缺少适用于多波长的频率锁定参考而较难实现。基于低温稀土离子掺杂晶体的激光稳频技术，不仅具有更低的温度系数（20Hz/mK），优于F-P腔一个量级的加速度敏感度（7×10-12/g），而且，频率锁定位置可在离子整个非均匀展宽谱线内连续调谐，不同稀土离子、不同晶体基质的非均匀展宽中心波长变化范围大，可为大范围波长调谐激光源的稳频提供锁频参考。因此，可用于大范围波长连续可调的激光稳频。本项目拟开展基于Tm3+离子掺杂晶体的790-795nm波段波长可调谐激光稳频技术研究，基于此验证基于低温稀土离子掺杂晶体的波长可调谐激光稳频技术原理，为更宽波长范围的波长可调谐超稳频激光源研究提供技术基础。

基于低温稀土离子掺杂晶体中的光谱烧孔效应的激光稳频技术是二十世纪末发展起来的新型稳频技术，该稳频技术以低温下稀土离子掺杂晶体中的光谱烧孔为频率锁定参考，有着更低的热噪声极限，具有更低的温度系数（20Hz/mK），优于F-P腔一个量级的加速度敏感度（7×10-12/g），而且，频率锁定位置可在离子整个非均匀展宽谱线内连续调谐，不同稀土离子、不同晶体基质的非均匀展宽中心波长变化范围大，可为大范围波长调谐激光源的稳频提供锁频参考。因此，可用于大范围波长连续可调的激光稳频。本项目开展了基于Tm3+离子掺杂晶体的790-795nm波段波长可调谐激光稳频技术理论和实验研究，验证了可调谐激光稳频技术原理，探索了多种新型光谱烧孔晶体性能，为更宽波长范围的波长可调谐超稳频激光源研究提供技术基础。