【作者】 路洋；

【导师】 姚建铨；

【作者基本信息】 天津大学 ， 物理电子学， 2007， 博士

【摘要】 THz波作为电磁波谱的最后一个研究波段,其研究,包括THz波辐射源、THz波探测和THz波的传输及应用(THz光谱,THz成像,THz无线通讯等),已成为世界各国普遍公认的重要领域。THz技术为科学技术的创新、国民经济发展和国家安全等方面提供了一个非常诱人的机遇。以美、日为首的各个发达国家正投入大量人力和物力致力于这方面的研究。积极开展THz科学技术的研究工作对我国具有重要的战略意义。其中,THz波辐射源的研究是重中之重。本研究是THz波辐射源方面研究的重要部分,即利用光子学方法获得THz波辐射。我们致力研究基于非线性光学的全固态、结构紧凑(小型化)、室温下运转、可调谐的THz波辐射源系统。这是THz技术应用研究的基础。获得THz波辐射的方法很多,主要分为电子学和光子学两个大方向,本文的研究属于光子学领域,并且主要是采用非线性光学方法,包括非线性光学差频、THz波参量振荡和光学Cherenkov辐射等。国际上,非线性光学方法获得THz波辐射的研究水平已有目共睹,其中无机晶体中非线性光学差频获得THz波辐射的峰值功率已到几个kW;THz波参量振荡获得的相干THz波辐射已应用在高精度,高速数据采集的THz波光谱仪。目前国内差频THz波输出较国际水平有很大差距;应用研究集中在THz光谱和成像方面,这方面研究由于是同国外相关单位合作,所以水平同国际相当。本文作者查阅研读了大量相关文献资料,在理论上提出了周期极化晶体THz波参量振荡新的辐射结构;并给出了差频THz波辐射相关研究结果;实验上已获得稳定的双波长线偏振态输出,达到国际最高水平,目前实验成果和进度受限于THz波探测器。本文创新点:理论上首次给出倾斜周期极化铌酸锂晶体差频侧面辐射THz波的理论模型,并根据模型进行分析研究;理论上首次提出周期极化晶体垂直侧面辐射THz波参量振荡器的实验设计方案;理论上给出LD端面泵浦1064和946 nm双波长连续振荡阈值模型,研究了温度对输出功率的影响;实验上获得国际最高水平5.12 W功率输出;实验上获得领域内端面泵浦1318.8和1338.2 nm双波长连续、准连续最高功率输出。更多还原

【Abstract】 The terahertz region of the electromagnetic spectrum spans the frequency range between the mid-infrared and the millimeter/microwave. This region has not been exploited fully to date owing to the limited number of suitable radiation sources and detectors. The researches including THz radiation source, THz detector, THz transmission and application (THz spectrum, THz imaging, THz wireless communication etc.) have been recognized research field in the world. THz technology has provided an attractive chance for the creation of science, the development of national economy and national security. Some developed countries such as America and Japan are devoting plenty of human and material resources to the THz research. Fully expanding research on THz science and technology has been of important strategetic meaning for our country. Moreover the research on THz source is the most important aspect of all. Our research belongs to the generation of THz radiation by using photonics methods. We are dedicating ourselves to research on all-solid-state, compactable, room-temperature, tunable THz radiation system via nonlinear optics because it is the foundation of THz wave application. The methods of THz generation can be divided into electronics and photonics. We use nonlinear optical method to obtain THz wave which belongs to photonics including nonlinear optical difference frequency generation, THz wave parametric oscillator and Cherenkov radiation etc. The author introduced new radiation structure of PPLN-THz parametric oscillator in theory and obtained conclusions of THz radiation via difference frequency generation based on seeking and reading plenty of articles. Experimentally we demonstrated stable dual-wavelength output to the best of our knowledge it is the highest level.Innovations:In theory introduced the model of surface-emitted THz wave by difference frequency generation in slant-strip-type PPLN for the first time and made necessary analyses based on the modelIn theory introduced new radiation structure of PPLN-THz parametric oscillator and obtained conclusions of THz radiation via difference frequency generation for the first timeIn theory established a threshold model for simultaneous dual-wavelength laser and analyzed the effects of the crystal temperature distributions determined by the incident power on the thresholds of simultaneous dual-wavelength laserTo the best of our knowledge, the output of 5.12 W is the highest simultaneous dual-wavelength CW operation using the quasi-three-level transition at 946 nm and the four-level transition at 1064 nm of a Nd:YAG crystal end-pumped by an LD. Experimentally obtained end-pumped 1318.8 and 1338.2nm dual-wavelength laser with the highest output power in our research field更多还原