【作者】 谢臻达；

【导师】 祝世宁；

【作者基本信息】 南京大学 ， 凝聚态物理， 2011， 博士

【摘要】 近年来,光学微腔作为一种集成化的光学器件,在光传感,计算和通信等方而受到了人们越来越多的关注。在非线性光学领域,亚相干长度的微腔还可以用来补偿非线性作用的相位失配,从而大大提高非线性转换的效率。早在1962年,Bloembergen等人就首先提出了这种“腔相位匹配”(cavity phase matching,简称CPM)的概念,并引发了此后人们一些理论上的探讨。本论文首次实验验证了CPM原理,并制成一系列不同功能的片状光参量振荡器(sheet optical paramctric oscillator,简称SOPO),展示了它们在非线性频率转换方而的些独有的特性和优势,并进一步将研究拓展到量子光学领域,主要内容包括：1.首先简要介绍CPM的非线性参量过程,并从理论上引入并分析了SOPO内特性。与其他的相位匹配方式比较,腔相位匹配具有集成化、高效率、高亮度、适用性广的特点。2.研制了基于KTP晶体的SOPO,通过Ⅱ类相位匹配首次实验验证了CPM的光参量过程。获得了频率近简并的单纵模、窄线宽、可调谐脉冲输出,峰值功率达到220kW,斜率效率23.8%。3.研制了基于铌酸锂晶体的Ⅰ型CPM的SOPO,在近简并点附近获得了可调谐的频率梳输出,覆盖宽度可以超过50nm,斜率效率达22.6%;在远离简并点的情况下,可以获得850nm和1400nm附近的可调谐窄线宽的信号/闲置光束对,分别对应绝原子的特征谱线和光通讯波段,斜率效率可达29.4%。并预言了0类CPM的SOPO,有望实现超宽调谐范围的单纵模中红外输出。4.我们在对SOPO的经典非线性光学效应研究的基础上,进一步对相对应的自发过程进行了研究。结果表明通过CPM可以对产生的非经典光的频谱进行调制,获得窄线宽或者具有梳状频谱的双光子对。并理论计算了上述具有不同的频谱分布的非经典光场的关联特性。5.研究了利用基于BBO晶体的SOPO产生偏振解纠缠的偏振纠缠双光子态的方案。由于CPM的参与,此种偏振纠缠双光子态的具有时间空间单模性好,亮度和纯度高的特点。在超短脉冲泵浦下,可以用来实现高可见度的多光子干涉,制备各种特殊的多粒子非经典态,用于量子信息。6.最后,本文还将对光场关联特性的研究拓展到强光,即阈值以上的光参量下转换过程。理论计算了高增益的光参量下转换的时间关联特性,结果表明在高增益的情况下参量下转换的关联仍然存在,并且性质与自发参量下转换光和热光的关联都不相同。尽管与自发过程相比高增益的光参量过程的关联的可见度较低,但是不易被破坏,具有更高的实用性。这种关联有可能用于的关联成像、光刻和高精度时钟对准等。更多还原

【Abstract】 In the recent years, optical microcavities have received considerable attention as integrated devices for the future applications in optical sensing, computing and communication. In the area of nonlinear optics, the sub-coherence-length microcavity can also be used to compensate for the phase mismatching, and thus greatly increase the efficiency of the nonlinear frequency conversion. This concept of "cavity phase matching"(CPM) was first proposed by Bloembergen et al. in1962, and induced some theoretical discussions after that. In this thesis we present the first experimental demonstration of CPM, and the realization of several sheet optical parametric oscillators (SOPO) for different applications. They have shown some unique features and advantages for the optical nonlinear frequency conversion, and the study has been extended to the area of quantum optics as well. The main results are listed as follows:1. We first briefly introduced the CPM nonlinear parametric process, and studied oscillation features of SOPO devices in theory. Compared to other phase matching methods, CPM features in high efficiency, high power and broad applicability for intergraded devices.2. We developed an SOPO using KTP crystal and realized type Ⅱ CPM nonlinear process for the first time. Tunable near-frequency-degenerate parametric outputs presented single-longitudinal-mode (SLM), narrow linewidth oscillation. The peak output power reached220kW and the slope efficiency was23.8%. 3. We developed the SOPOs using type-I CPM based on Lithium Niobate crystal. Frequency comb output was obtained near degenerate point, with spectral bandwidth of over50nm and slope efficiency of22.6%. In the highly nondegenerate case, tunable SLM twin beams could be obtained at around850nm and1400nm, which corresponded to the typical line of cesium and telecommunication band. The sloped efficiency was measured to be29.4%. We also predicted SOPO using type0CPM, where SLM mid-infrared output can be expected with ultra-broadband tuning range.4. Based on the study on classical nonlinear optical effects of SOPO, we further studied the corresponding spontaneous processes. The results showed that CPM could also modulate the spectrum of the output nonclassical light, where narrow linewidth or frequency comb spectrum could be obtained. We also theoretically studied the correlation effects for these nonclassical optical fields.5. We proposed the generation of frequency-uncorrelated polarization-entangled two-photon state based on SOPO using BBO crystal. Because the participation of CPM, this two-photon state showed high purity and brightness for both transverse and longitudinal modes. With ultra-fast laser pump, it might be used to realize high visibility multi-photon interference and generate multi-particle non-classical states for quantum information.6. In the end, we extended the study for the correlation effect of light field to the case of stimulated parametric down conversion. The theoretical calculation showed clear temporal correlation even under the high-gain case. This kind of correlation is different from those of spontaneous parametric down conversion or thermal light. Although the correlation showed lower visibility than the spontaneous case, it is less fragile and thus more feasible for practical applications. It may be used for future correlation imaging, lithography and precise clock synchronization.更多还原