光学超晶格中红外光参量振荡器研究

发布时间：2018-03-03 03:06

  本文选题：中红外激光　切入点：光参量振荡　出处：《山东大学》2017年博士论文　论文类型：学位论文

【摘要】：2-5 μm波段中红外激光在大气中具有较强的穿透能力,而且众多原子及分子的特征吸收峰也坐落于该波段,因此该波段激光在前沿科学、军事、光谱学、遥感探测、医疗诊断等诸多领域都具有极其重要的应用价值,该波段激光器一直是国防和民用领域竞相研发的重点。利用光参量振荡器(OPO)技术,将成熟的近红外波段激光进行频率下转换,能够实现中红外波段激光的宽带、连续调谐输出,可以弥补一些离子掺杂(如Ho3+、Er3+ Tm3+)激光器在波长发射和调谐方面的不足。在众多非线性晶体材料中,基于准相位匹配的光学超晶格材料,特别是周期极化铌酸锂或钽酸锂晶体(PPLN、PPLT),具有非线性系数大、通光范围宽、波长调谐方式多样、生长制备较为容易、适合于1064nm泵浦等优点,是目前中红外大功率OPO的理想选择。拓宽中红外激光输出波长范围,提高OPO的转换效率、输出功率、光束质量和稳定性一直都是人们研究的方向。针对这一命题,本论文将泵浦源设计、光束整形以及OPO谐振腔设计相结合,选用周期性极化掺镁铌酸锂(PPMgO:LN)及化学计量比钽酸锂(PPSLT)晶体,实现了宽调谐窄线宽连续波,大能量长脉冲,多波长、宽调谐及高功率纳秒脉冲中红外OPO输出。具体内容主要包括:1.介绍了中红外激光的重要应用,对目前产生中红外激光的主要技术途径进行了对比,并概述了光学超晶格OPO的研究现状。2.简单介绍了相位匹配技术,描述了准相位匹配技术和实现波长调谐的原理与方法,对OPO基础知识及设计基本原则进行了介绍。3.结合单块非平面环形腔(NPRO)单频激光器和混合腔(Innoslab)板条激光放大器,开展宽调谐、窄线宽连续波中红外OPO研究。得到了 83.4 W、线宽17.69kHz的高功率 1064nm激光输出;并在基于PPMgO:LN的环形腔OPO中,实现了 1344.6-5103.2 nm的宽调谐窄线宽中红外激光输出。4.采用具有高峰值功率的脉冲模式工作的激光二极管(LD)作为泵浦源,进行了大能量长脉冲中红外OPO探索。以Nd:YVO4为激光增益介质,腔内泵浦PPMgO:LN晶体,在结构紧凑的直腔中,得到了大能量微秒量级脉冲参量光输出,3.336、3.500、3.789 μm 处的单脉冲能量分别为 3.99、3.31、2.50 mJ。5.研究了多波长、宽调谐纳秒中红外OPO。针对OPO需要偏振激光泵浦的特点,利用偏振分束技术,将由非偏振光纤激光分束后的两路偏振光共同耦合进同一块PPSLT晶体的两个不同通道,在同一谐振腔中,实现了四波长激光同时输出;利用多周期PPMgO:LN晶体,实现了 1346.6-5076.8 nm宽调谐纳秒中红外OPO输出。6.利用调Q激光技术,结合多级Innoslab板条放大器,对高功率中红外OPO进行了研究。用侧面抽运Nd:YLF调Q激光泵浦PPMgO:LN晶体,得到了单脉冲能量为1.1 mJ的3.796 μm中红外激光输出;以多级Innoslab板条放大器为OPO泵浦源,在3.791 μm和2 μm波段分别实现了 10.2 W和33.3 W的中红外激光输出。另外,在实验基础上进行工程化探索,设计并完成三台宽调谐、高功率纳秒中红外OPO样机,推动中红外激光技术的研究与示范应用。
[Abstract]:2-5 m wavelength infrared laser has a strong penetrating ability in the atmosphere, and the characteristics of a large number of atomic and molecular absorption peak also located in the band, the band laser at the forefront of science, military, spectroscopy, remote sensing, has very important application value in many fields such as medical diagnosis, the lasers have been key military and civilian fields. With the development of the optical parametric oscillator (OPO) technology, the near-infrared laser frequency conversion to mature, can realize the broadband mid infrared laser, tunable output, can make up for some ions (such as Ho3+, Er3+ Tm3+) laser at the wavelength of emission and shortcomings in terms of tuning in many nonlinear crystals, quasi phase matching optical superlattice materials especially based on periodically poled lithium niobate or lithium tantalate crystals (PPLN, PPLT), with a nonlinear coefficient Large optical wavelength tuning range, diversity, growth and preparation is easy, suitable for 1064nm pumping and other advantages, is the ideal choice for high power infrared OPO currently. To broaden the mid infrared laser output wavelength range, improve the conversion efficiency of OPO, output power, beam quality and stability have been a research direction. According to this proposition, this paper will design the pump source, beam shaping and OPO cavity design combined with periodically poled MgO doped lithium niobate (PPMgO:LN) and stoichiometric lithium tantalate (PPSLT) crystals, can achieve a wide tunable continuous wave, high energy long pulse, multi wavelength, wide tuning and high power nanosecond pulse infrared OPO output. The specific contents include: 1. introduced important application in infrared laser, the main ways of technology to produce mid infrared laser at present are compared, and an overview of optical superlattice OPO Briefly introduces the research status of.2. phase matching technology, describes the technology and principle and method of realizing wavelength tuning of quasi phase matching of OPO, basic knowledge and basic design principles are introduced with.3. monolithic non planar ring cavity single frequency laser (NPRO) and mixed cavity (Innoslab) slab laser amplifier, carry out wide tuning. Study on infrared continuous wave OPO in narrow linewidth. By 83.4 W high power 1064nm laser linewidth of 17.69kHz; based on ring cavity OPO PPMgO:LN, 1344.6-5103.2 nm to achieve wide tunable narrow linewidth in the infrared laser light output.4. laser diode with high peak power pulsed mode (LD) as the the pump source, the high energy long pulse infrared OPO exploration. Using Nd:YVO4 as the laser gain medium pumped PPMgO:LN crystal, the straight cavity of a compact structure, the high energy nanosecond pulse 鍐插弬閲忓厜杈撳嚭,3.336,3.500,3.789 渭m 澶勭殑鍗曡剦鍐茶兘閲忓垎鍒�涓� 3.99,3.31,2.50 mJ.5.鐮旂┒浜嗗�氭尝闀�,瀹借皟璋愮撼绉掍腑绾㈠�朞PO.閽堝�筄PO闇，

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