【作者】 赵璞；

【导师】 姚建铨；

【作者基本信息】 天津大学 ， 物理电子学， 2007， 硕士

【摘要】 结合准相位匹配技术,光学参量转换——包括光学参量直接产生和光学参量振荡——是获得宽调谐、高效率的近红外和中红外光源的有效方法。研究光学参量转换过程的最重要的部分是如何确保泵浦光以及所获得的信号光和闲频光之间的相位匹配。与传统的双折射相位匹配技术相比,准相位匹配技术的优点是很明显的:可以时刻确保共线的相位匹配;可以获得很高的转换效率;可以灵活地对输出光波长进行精确的调谐。正因为如此,基于准相位匹配技术的各种周期极化晶体已被广泛地使用在非线性光学频率变换领域内。周期极化晶体还有一个特别突出的优点,就是它们的极化周期可以根据需要进行人为的设计,这样使得准相位匹配技术也被广泛地使用在产生太赫兹波的研究当中(用于产生供非线性光学差频使用的双波长光源或者直接被用于产生太赫兹辐射)。本论文所讨论的内容主要是基于准相位匹配光学参量转换的原理而展开的。论文的主要内容以及创新点简述如下:1.在实验中完成了一个基于周期极化铌酸锂晶体的高转换效率、低阈值、高重复频率的光学参量产生器。从1064 nm泵浦光到信号光的光光转换效率达到了62.7%,是目前文献报道中所获得的最高的转换效率。2.研究了使用多周期的周期极化铌酸锂晶体作为频率变换器件的准连续内腔光学参量振荡器。信号光平均功率的输出达到409 mW,对应的从808 nm泵浦光到信号光功率输出的光光转换效率为8.8%。3.设计了一种基于周期极化铌酸锂晶体的可调谐双波长光学参量产生器。首次利用声光器件将1064 nm泵浦光分为两束,并将分束后的泵浦光入射到周期极化铌酸锂晶体不同的极化周期部分,从而获得双波长光的输出。以这种泵浦方式获得双波长光输出的设计未见过报道。4.研究了使用内腔光学参量振荡器获得双波长光的输出。在同一个光学参量振荡器腔内放入两块同样的周期极化铌酸锂晶体作为频率变换器件,并可以对输出的双波长光信号的波长进行分别调谐。以这种方式获得可调谐双波长输出的研究也是首次提出。5.在理论上讨论了基于Slant-Stripe-Type结构的周期极化铌酸锂晶体获得可调谐太赫兹波参量产生的一种设计。6.设计和搭制了一台基于周期极化铌酸锂晶体的内腔光学参量振荡器样机。更多还原

【Abstract】 Based on quasi-phase-matching (QPM) technology, optical parametric conversion——including optical parametric generator (OPG) and optical parametric oscillator (OPO)——can be a powerful method to generate widely tunable, high efficient near and mid infrared radiation. The most important part of the researches involved optical parametric conversion is how to make the phase matched. Compared with the traditional birefringent phase matching (BPM) technology, QPM technology’s advantages are obvious: collinear phase matching scheme, high conversion efficiency, precise and flexible wavelength tuning methods. Thus, the periodically poled crystals based on QPM technology have been widely used as the frequency converter in the field of nonlinear optics. Besides, because the poled period of the periodically poled crystals can be manually designed, the QPM technology is also widely applied in the generation of terahertz wave radiation (used as dual-wavelength source for difference-frequency-generation or directly used as the generator).The researches discussed in this dissertation are mainly based on the principles of quasi-phase-matched optical parametric conversion. The brief description of the dissertation and some innovative places are presented as follows.1. A high conversion efficiency, low threshold, high-repetition-rate periodically poled lithium niobate (PPLN) OPG was experimentally demonstrated. The conversion efficiency of 62.7% is the highest ever reported.2. We obtained 409 mW average signal power from an actively Q-switched intracavity optical parametric oscillator (IOPO) based on multi-grating PPLN crystal. This output power corresponded to a conversion efficiency of 8.8% with respect to the diode pump power.3. We designed a tunable dual-signal OPG based on multi-grating PPLN by using an acousto-optic beam splitter. The pumping scheme is innovative.4. A dual-wavelength IOPO using two PPLN crystals was designed and experimentally demonstrated. This way of generating dual-wavelength radiation was also firstly reported.5. We theoretically analyzed the tunable parametric generation of terahertz radiation in Slant-Stripe-Type PPLN crystals.6. A model machine of the PPLN IOPO system was designed and produced.更多还原