基于新型金纳米材料的锁模激光器研究
发布时间：2018-10-18 20:01
【摘要】：锁模光纤激光器由于其峰值功率大、脉冲能量高、结构简单、稳定性好等优良特性,而被广泛应用于光纤通信、光传感、材料加工、医疗以及国防等领域。近年来,许多研究者对于在光纤激光器中引入新型可饱和吸收体来实现锁模激光输出有了深入的研究。金纳米材料具有较高的非线性系数和超快的响应时间,以及良好的光纤兼容性和易于制备等优点,而且利用金纳米材料的可饱和吸收特性也可以实现脉冲激光输出,因此基于金纳米材料的可饱和吸收体受到了人们的广泛关注。金纳米材料在光信息存储、生物医疗、新能源研究等领域有着重要的应用。为了更好地探索金纳米材料的可饱和吸收特性,首先需要制备不同形貌、尺寸的金纳米材料。通过研究发现,不同长径比的金纳米双锥和金纳米棒薄膜在相应的激光运转波段均具有可饱和吸收特性,其有望被用于研制可见-红外波段的调Q或锁模激光器。基于以上发现,我们制备了金纳米双锥和金纳米棒溶液,结合聚甲基丙烯酸甲酯PMMA做成薄膜,在实验上分别制作出基于金纳米双锥和金纳米棒的光纤集成型可饱和吸收体,首次成功的实现了基于金纳米双锥材料的锁模激光稳定运转,其输出波长为1078 nm,在泵浦功率为118 mW时输出的最大平均功率为1.87 mW,对应的光光转换效率为1.6%,此时脉冲的重复频率为30.65 MHz,脉冲宽度为95.8 ps,对应的单脉冲能量为0.06 nJ;采用金纳米棒做可饱和吸收体,我们成功的实现了中心波长在1030 nm附近的锁模激光输出,最大输出功率为2.13 mW,对应的光光转换效率为1.34%,脉冲宽度为20 ps,重复频率为27.45 MHz,对应的单脉冲能量为77.6 pJ。实验结果表明,金纳米双锥和金纳米棒材料均具有优良的可饱和吸收特性,作为可饱和吸收体都能获得较短的激光脉冲输出,通过优化材料参数有望获得更短脉冲输出。实验中对锁模激光失调的原因进行了实验研究,发现高泵浦功率下可饱和吸收体的过饱和效应是引起锁模激光不稳定的主要原因,此外,金离子受热会发生凝聚,而且,PMMA受热也不稳定,后期我们将试图采取温控的手段来控制材料的温度,从而获得稳定的锁模激光。在后续工作中,我们还打算将输出光脉冲做种子源放大,从而获得功率放大。
[Abstract]:Mode-locked fiber lasers are widely used in the fields of optical fiber communication, optical sensing, material processing, medical treatment and national defense because of their high peak power, high pulse energy, simple structure and good stability. In recent years, many researchers have deeply studied the application of new saturable absorbers in fiber lasers to achieve mode-locked laser output. Gold nanomaterials have the advantages of high nonlinear coefficient, ultra-fast response time, good optical fiber compatibility and easy preparation, and pulse laser output can be realized by using the saturable absorption characteristics of gold nanomaterials. Therefore, saturable absorbers based on gold nanomaterials have attracted wide attention. Gold nanomaterials have important applications in optical information storage, biomedicine, new energy research and so on. In order to better explore the saturable absorption characteristics of gold nanomaterials, it is necessary to prepare gold nanomaterials with different morphologies and sizes. It is found that gold nanometers with different aspect ratios have saturable absorption properties in the corresponding laser operating band, which is expected to be used to develop Q-switched or mode-locked lasers in the visible and infrared band. Based on the above findings, we have prepared gold nanometre cones and gold nanorods solutions, and made films with poly (methyl methacrylate) PMMA. In experiments, we have fabricated optical fiber integrated saturable absorbers based on gold nanometers and gold nanorods, respectively. For the first time, the stable operation of the mode-locked laser based on gold nanometer-conical material has been successfully realized. Its output wavelength is 1078 nm, and the maximum average output power is 1.87 mW, when the pump power is 118 mW. The optical conversion efficiency corresponding to 1.87 mW, is 1.6. The repetition rate of the pulse is 30.65 MHz, and the single pulse energy corresponding to 95.8 ps, is 0.06 nJ;. Using gold nanorods as saturable absorbers, We have successfully realized the mode-locked laser with center wavelength of 1030 nm. The maximum output power of 2.13 mW, corresponds to the optical conversion efficiency of 1.34, and the pulse width of 20 ps, repetition rate of 27.45 MHz, corresponds to the single pulse energy of 77.6 pJ.. The experimental results show that both gold nanometers and gold nanorods have excellent saturable absorption properties. As saturable absorbers, both can obtain shorter laser pulse output and can be expected to obtain shorter pulse output by optimizing material parameters. The reason of the misalignment of mode-locked laser is studied experimentally. It is found that the supersaturation effect of the saturable absorber at high pump power is the main cause of the instability of the mode-locked laser. In addition, the gold ions will be condensed when heated. Furthermore, the PMMA is not stable by heating. In the later stage, we will try to control the temperature of the material by means of temperature control, so as to obtain a stable mode-locked laser. In the following work, we also intend to amplify the output light pulse as seed source to obtain power amplification.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
[Abstract]:Mode-locked fiber lasers are widely used in the fields of optical fiber communication, optical sensing, material processing, medical treatment and national defense because of their high peak power, high pulse energy, simple structure and good stability. In recent years, many researchers have deeply studied the application of new saturable absorbers in fiber lasers to achieve mode-locked laser output. Gold nanomaterials have the advantages of high nonlinear coefficient, ultra-fast response time, good optical fiber compatibility and easy preparation, and pulse laser output can be realized by using the saturable absorption characteristics of gold nanomaterials. Therefore, saturable absorbers based on gold nanomaterials have attracted wide attention. Gold nanomaterials have important applications in optical information storage, biomedicine, new energy research and so on. In order to better explore the saturable absorption characteristics of gold nanomaterials, it is necessary to prepare gold nanomaterials with different morphologies and sizes. It is found that gold nanometers with different aspect ratios have saturable absorption properties in the corresponding laser operating band, which is expected to be used to develop Q-switched or mode-locked lasers in the visible and infrared band. Based on the above findings, we have prepared gold nanometre cones and gold nanorods solutions, and made films with poly (methyl methacrylate) PMMA. In experiments, we have fabricated optical fiber integrated saturable absorbers based on gold nanometers and gold nanorods, respectively. For the first time, the stable operation of the mode-locked laser based on gold nanometer-conical material has been successfully realized. Its output wavelength is 1078 nm, and the maximum average output power is 1.87 mW, when the pump power is 118 mW. The optical conversion efficiency corresponding to 1.87 mW, is 1.6. The repetition rate of the pulse is 30.65 MHz, and the single pulse energy corresponding to 95.8 ps, is 0.06 nJ;. Using gold nanorods as saturable absorbers, We have successfully realized the mode-locked laser with center wavelength of 1030 nm. The maximum output power of 2.13 mW, corresponds to the optical conversion efficiency of 1.34, and the pulse width of 20 ps, repetition rate of 27.45 MHz, corresponds to the single pulse energy of 77.6 pJ.. The experimental results show that both gold nanometers and gold nanorods have excellent saturable absorption properties. As saturable absorbers, both can obtain shorter laser pulse output and can be expected to obtain shorter pulse output by optimizing material parameters. The reason of the misalignment of mode-locked laser is studied experimentally. It is found that the supersaturation effect of the saturable absorber at high pump power is the main cause of the instability of the mode-locked laser. In addition, the gold ions will be condensed when heated. Furthermore, the PMMA is not stable by heating. In the later stage, we will try to control the temperature of the material by means of temperature control, so as to obtain a stable mode-locked laser. In the following work, we also intend to amplify the output light pulse as seed source to obtain power amplification.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
【参考文献】
相关期刊论文 前8条
1 邵磊;阮琦锋;王建方;林海青;;局域表面等离激元[J];物理;2014年05期
2 许阳;康U，
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