【摘要】：鎖模光纖激光器由于其峰值功率大、脈沖能量高、結(jié)構(gòu)簡單、穩(wěn)定性好等優(yōu)良特性,而被廣泛應(yīng)用于光纖通信、光傳感、材料加工、醫(yī)療以及國防等領(lǐng)域。近年來,許多研究者對于在光纖激光器中引入新型可飽和吸收體來實現(xiàn)鎖模激光輸出有了深入的研究。金納米材料具有較高的非線性系數(shù)和超快的響應(yīng)時間,以及良好的光纖兼容性和易于制備等優(yōu)點,而且利用金納米材料的可飽和吸收特性也可以實現(xiàn)脈沖激光輸出,因此基于金納米材料的可飽和吸收體受到了人們的廣泛關(guān)注。金納米材料在光信息存儲、生物醫(yī)療、新能源研究等領(lǐng)域有著重要的應(yīng)用。為了更好地探索金納米材料的可飽和吸收特性,首先需要制備不同形貌、尺寸的金納米材料。通過研究發(fā)現(xiàn),不同長徑比的金納米雙錐和金納米棒薄膜在相應(yīng)的激光運轉(zhuǎn)波段均具有可飽和吸收特性,其有望被用于研制可見-紅外波段的調(diào)Q或鎖模激光器�；谝陨习l(fā)現(xiàn),我們制備了金納米雙錐和金納米棒溶液,結(jié)合聚甲基丙烯酸甲酯PMMA做成薄膜,在實驗上分別制作出基于金納米雙錐和金納米棒的光纖集成型可飽和吸收體,首次成功的實現(xiàn)了基于金納米雙錐材料的鎖模激光穩(wěn)定運轉(zhuǎn),其輸出波長為1078 nm,在泵浦功率為118 mW時輸出的最大平均功率為1.87 mW,對應(yīng)的光光轉(zhuǎn)換效率為1.6%,此時脈沖的重復(fù)頻率為30.65 MHz,脈沖寬度為95.8 ps,對應(yīng)的單脈沖能量為0.06 nJ;采用金納米棒做可飽和吸收體,我們成功的實現(xiàn)了中心波長在1030 nm附近的鎖模激光輸出,最大輸出功率為2.13 mW,對應(yīng)的光光轉(zhuǎn)換效率為1.34%,脈沖寬度為20 ps,重復(fù)頻率為27.45 MHz,對應(yīng)的單脈沖能量為77.6 pJ。實驗結(jié)果表明,金納米雙錐和金納米棒材料均具有優(yōu)良的可飽和吸收特性,作為可飽和吸收體都能獲得較短的激光脈沖輸出,通過優(yōu)化材料參數(shù)有望獲得更短脈沖輸出。實驗中對鎖模激光失調(diào)的原因進(jìn)行了實驗研究,發(fā)現(xiàn)高泵浦功率下可飽和吸收體的過飽和效應(yīng)是引起鎖模激光不穩(wěn)定的主要原因,此外,金離子受熱會發(fā)生凝聚,而且,PMMA受熱也不穩(wěn)定,后期我們將試圖采取溫控的手段來控制材料的溫度,從而獲得穩(wěn)定的鎖模激光。在后續(xù)工作中,我們還打算將輸出光脈沖做種子源放大,從而獲得功率放大。
[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.
【學(xué)位授予單位】：山東理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN248

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相關(guān)期刊論文 前8條

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本文編號：2280212