【作者】 姜玉刚；

【导师】 陈德应；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2011， 博士

【摘要】 染料激光器因调谐范围宽、效率高等优点,在科研、军事、医疗等领域具有重要的应用前景。传统液体染料激光器由于染料溶液循环冷却系统庞大、染料和溶剂有毒易燃、需定期更换和清洗循环系统容器和管道等缺点,大大限制了它们的应用。相比之下,固体染料激光器在保留了前者泵浦方式多样、调谐范围宽等优点的同时,还具有全固化、体积小、重量轻、使用及保存方便以及成本低等优点,因此研究固体染料激光器具有非常重要的意义。为突破目前固体染料激光器研究尚停留在小能量激光泵浦范围的现状。本文首先对固体染料激光介质及可调谐染料激光器的发展状况做了系统的介绍和分析。在染料分子光降解机理、固体基质光破坏、甲基丙烯酸甲酯(MMA)本体聚合机理研究基础上,分别采用固体基质改性、掺杂改性、固体基质和掺杂共同改性的方法,研制了抗损伤阈值高、效率高、寿命长(光稳定性好)的改性聚合物基质固体染料激光介质,并获得了宽调谐范围、大能量的固体染料激光输出。为提高固体染料激光介质的使用寿命、激光效率和抗损伤阈值等性能,本文主要采用了添加有机小分子甲醇、添加甲醇和香豆素染料共掺、添加甲醇和单体共聚等改性方法,研制了掺杂PM系列固体染料激光介质,并研究了改性对固体染料激光输出特性的影响。对于以甲醇改性的共聚物为基质的掺杂PM567固体染料激光介质,当甲醇掺杂体积比为15%时,重复频率5Hz,单脉冲能量100mJ泵浦,使用寿命最长达到278 000次,对应的归一化光稳定性为180.7GJ/mol,相对于未改性时提高了8.7倍,激光输出斜率效率最高达到63.31%,抗损伤阈值为6.7 J/cm2。以甲醇改性的PMMA为基质,当PM567与C540A掺杂摩尔比为2:5时,使用寿命最长达到618 000次,归一化光稳定性为401.7GJ/mol,抗损伤阈值达7.9 J/cm2。在大能量激光泵浦条件下,以掺杂PM567、PM580、PM597固体染料激光介质作为工作介质,分别获得了432、412和448mJ大能量的宽带固体染料激光输出。针对目前固体染料激光介质调谐范围窄、激光转换效率低等缺点,本文基于光栅掠入射调谐基本原理,设计了可调谐窄线宽激光振荡结构,开展了单掺、共掺和改性固体染料激光介质的可调谐输出特性研究及在可调谐工作条件下的光稳定性研究。以甲醇改性的掺杂PM567、PM580、PM597和PM650固体染料作为工作介质,获得了调谐范围分别为51.7、52.1、51.5和63.9nm的窄线宽固体染料激光输出,对应的激光效率分别达到42.59%、42.7%、37.62%和9.39%。对掺杂PM580固体染料输出的宽带和窄线宽激光光束质量进行了测量,结果:Mx2因子为10.9和4.1,My2因子为10.7和3.9。研究了可调谐固体染料激光器在不同工作波长处的光稳定性,实验结果表明当固体染料激光介质工作在转换效率越高的波长处时,光稳定性就越好。本论文在传统可调谐窄线宽固体染料激光器研究基础上,提出了基于液晶及分布反馈式结构的可集成染料激光调谐方案,并开展了初步的理论与实验研究。采用相干泵浦PM567染料掺杂液晶波导介质,获得了从556nm到571nm的窄线宽可调谐染料激光输出,为后续染料掺杂液晶介质在外加电场作用下的可调谐窄线宽激光输出特性研究奠定了基础。为获得单脉冲大能量、宽调谐范围的窄线宽固体染料激光和紫外激光输出,本文设计了可调谐窄线宽固体染料激光“振荡-放大”和“放大-倍频”结构,实验研究了固体染料激光放大调谐输出特性及倍频输出特性。以掺杂PM567、PM580和PM597固体染料作为放大介质,分别获得了调谐范围为48、48和58nm的窄线宽固体染料激光输出,在560、560和590nm波长处的斜率效率分别为51.39%、50.62%和36.2%,对应的最大输出能量达到113.9、116.2和114.1mJ。采用BBO倍频晶体,以掺杂PM597固体染料作为放大增益介质,获得了从279~305nm范围内连续调谐的紫外激光输出,最大输出能量为6.94mJ。结果表明,采用掺杂PM系列固体染料激光介质作为放大增益介质,可以获得大能量、宽调谐范围的窄线宽固体染料激光和紫外激光输出,为固体染料激光器向实用化发展提供了有力的参考依据。更多还原

【Abstract】 Dye lasers have wide range of applications in many areas such as science, military, and medicine for their advantages including broad tunable range and high efficiency. Conventional liquid dye lasers cannot reach the comprehensive applications because their complicated liquid dyes solutions circulatory systems, toxic and flammable dyes and solvents, periodic replacing and cleanouting circulatory systems and conduits. Keeping the advantages of liquid dye lasers for various pumping styles and wide tunable range in the visible light waveband, solid-state dye lasers also have other advantages, such as all solid-state construction, little capacity, light weight, convenience for use and conservation, low cost and so on.Recently the research of solid-state dye lasers is mainly rest on low laser energy pump. The dissertation first systematically introduces and analyzes the development of solid-state dye mediums and tunable solid-state dye lasers. The dissertation studies the photodestruction mechanism of solid-host and photodegration of dye molecules, mass polymeric mechanism of MMA, and uses modified solid hosts method, doping modified method, modified solid hosts and doping modified together method, and dedicates to prepare modified solid-state dye mediums with high laser damage threshold, high laser efficiency, long lifetime (good photostability), and obtains solid-state dye laser output with wide tunable range, high dye laser energy.In order to enhance the lifetime, efficiency, damage threshold of solid-state dye mediums, the dissertation mainly chooses the methods with addition of low moleculer methanol, the methods with addition of low moleculer methanol and Coumarin dyes, the methods with addition of low moleculer methanol and other monomer, and prepares solid-state mediums doped with PM dyes and researches the impact of modification on their output characteristics. In the solid-state dye samples based on modified copolymers of MMA and HEMA with methanol doped with PM567, when the volume percent of doped methanol is 15%, the longest lifetime is 278 000 shots, and the corresponding normalized photostability is 180.7 GJ/mol, the photostability increased 8.7 times, the highest laser efficiency is 63.31%, and laser damage threshold is 6.7 J/cm2. In the solid-state dye samples based on modified PMMA with methanol co-doped with PM567 and C540A, the longest lifetime is 618 000 shots, the corresponding normalized photostability is 401.7 GJ/mol, and laser damage threshold reaches 7.9 J/cm2. Our results are the best are the present time. Solid-state dye samples doped with PM567, PM580, and PM597 are used as operating mediums under high pulse energy pump, the corresponding maxium dye laser output energy reach 432mJ, 412mJ, and 448mJ.Due to solid-state dye laser with narrow tunable range and low laser efficiency recently, depending on the basic theory of near-grazing-incidence grating, the dissertation designs tunable narrow linewidth laser oscillator cavity, and researchs tunable dye laser output characteristics of single-doped, co-doped and modified solid-state dye mediums. The photostability of tunable narrow linewidth solid-state dye lasers are also studied. When solid-state dye samples based on modified PMMA with methanol doped with PM567, PM580, PM597, PM650 are used as operating mediums, the narrow linewidth dye laser output with tunable ranges of 51.7nm, 52.1nm, 51.5nm, 63.9nm are obtained, and the corresponding laser efficiency are 42.59%, 42.7%, 37.62%, 9.39%. The tunable rrange is the best for the single-doped solid-state dye medium at the present time. Using solid-state dye sample doped with PM580 as operating medium, the broad and narrow band laser beam quality factor M2 are measured, and the beam quality factors are estimated to be Mx2=10.9 and 4.1 in horizontal direction and My2=10.7 and 3.9 in vertical direction for broadband and narrowband laser. The photostability of tunable narrow linewidth solid-state dye lasers under different pump energy density and different operating wavelength are first studied and the results show that the photostability are better when the samples operate at the emission wavelength with high conversion efficiency.Based on DFB solid-state dye laser with traditional refraction modulation, the dissertation introduces the dye into the liquid crystal and designs DFB structure for obtaining integrated tunable dye laser. The dye laser output characteristics are researched by theoretical and experimental methods. Tunable narrow linewidth dye laser output properties of PM567 doped nematic liquid crystal under holographic excitation are studied using theoretical and experiment methods, and tunable narrow linewidth dye laser output from 556 nm to 571 nm are obtained. The results are very important for future research on tunable dye laser output with dye doped LC under applied electric field and its practical application.In order to obtain tunable narrow linewidth solid-state dye laser and ultraviolet laser output with high pulse energy and wide tunable range, the dissertation designs tunable narrow linewidth solid-state dye laser oscillator-amplifier and amplifier-doubling frequency configuration, and researches solid-state dye laser amplified output characteristics and doubling frequency output characteristics. Using solid-state dye samples doped with PM567, PM580, and PM597 as amplified operating mediums, narrow linewidth solid-state dye laser output with tunable range 48nm, 48nm, 58nm are obtained, and the highest slope efficiency of 51.39% at 560nm, 50.62% at 560nm, 36.25% at 590nm are obtained, and the corresponding maximum output energy are 113.9mJ, 116.2mJ, 114.1mJ. Using BBO crystal to frequency double the dye laser into ultraviolet and solid-state dye sample doped with PM597 as operating medium, ultraviolet dye laser output are demonstrated with a continuous tunable range from 279 to 305 nm, and the highest UV laser output energy reaches 6.94mJ. The experiment results show that the use of solid-state dye laser samples as operating medium, tunable narrow linewidth solid-state dye laser and ultraviolet laser output with a single high pulse energy can be obtained, and reach practical level.更多还原