Volume 50 Issue 1
Jan.  2021
Turn off MathJax
Article Contents

Zhang Bin, Li Ying, Liu Binghai. 1 123 nm passively Q-switched Nd: YAG laser based on gold nanocages and MoS2 saturable absorbers[J]. Infrared and Laser Engineering, 2021, 50(1): 20200084. doi: 10.3788/IRLA20200084
Citation: Zhang Bin, Li Ying, Liu Binghai. 1 123 nm passively Q-switched Nd: YAG laser based on gold nanocages and MoS2 saturable absorbers[J]. Infrared and Laser Engineering, 2021, 50(1): 20200084. doi: 10.3788/IRLA20200084

1 123 nm passively Q-switched Nd: YAG laser based on gold nanocages and MoS2 saturable absorbers

doi: 10.3788/IRLA20200084
  • Received Date: 2020-03-19
  • Rev Recd Date: 2020-05-14
  • Available Online: 2020-06-09
  • Publish Date: 2021-01-25
  • Gold nanocages (GNCs) were successfully prepared by seed-mediated method and its nonlinear saturated absorption characteristic at 1123 nm was verified for the first time. As a comparison, a MoS2 saturated absorber was prepared. Based on GNCs and MoS2 as saturable absorber (SA), respectively, passively Q-switched Nd: YAG lasers at 1 123 nm were demonstrated.When Q-switched laser with MoS2 as SA, Q-switched pulse with the shortest pulse duration of 412 ns and maximum pulse repetition rate of 233 kHz was achieved under the pump power of 6.81 W with the maximum average output power of 208 mW. When Q-switched laser with GNCs as SA, Q-switched pulse with the shortest pulse duration of 253 ns and maximum pulse repetition rate of 326 kHz was achieved under the pump power of 6.04 W with the maximum average output power of 221 mW. Compared with the experimental results of MoS2 Q-switched laser, the gold nanocage Q-switched laser has higher output power and efficiency, narrower pulse width and higher repetition rate. These results indicate a great potential of the GNCs film as SA in the near-infrared region.
  • [1] Booth I J, Archambault J L, Ventrudo B F. Photodegradation of near-infrared-pumped Tm(3+)- doped ZBLAN fiber upconversion lasers [J]. Optics Letters, 1996, 21(5): 348-350. doi:  10.1364/OL.21.000348
    [2] Gao J, Dai X J, Zhang L, et al. All-solid-state continuous-wave yellow laser at 561 nm under in-band pumping [J]. Journal of the Optical Society of America B, 2013, 30(1): 95-98. doi:  10.1364/JOSAB.30.000095
    [3] Marling J. 1.05-1.44 μm tunability and performance of the CW Nd3+: YAG laser [J]. IEEE Journal of Quantum Electronics, 1978, 14(1): 56-62. doi:  10.1109/JQE.1978.1069667
    [4] Zhang S S, Wang Q P, Zhang X Y, et al. Continuous-wave ceramic Nd: YAG laser at 1123 nm [J]. Laser Physics Letters, 2009, 6(12): 864-867. doi:  10.1002/lapl.200910094
    [5] Li C Y, Bo Y, Xu Y T, et al. 219.3 W CW diode-side-pumped 1123 nm Nd: YAG Iaser [J]. Optics Communications, 2010, 283: 2885-2887. doi:  10.1016/j.optcom.2010.03.039
    [6] Chen Y F, Lan Y P, Tsai S W. High-power diode-pumped actively Q-switched Nd: YAG laser at 1123 nm [J]. Optics Communications, 2004, 234(1-6): 309-313. doi:  10.1016/j.optcom.2004.02.009
    [7] Tang Y, Zhang X Y, Wang Q P, et al. High-efficiency diode-pumped acousto-optically Q-switched 1123 nm ceramic Nd: YAG laser [J]. Laser Physics, 2011, 21(4): 695-699. doi:  10.1134/S1054660X11070280
    [8] Koechner W. Solid-State Laser Engineering[M]. 6th ed. New York: Springer, 2006: 488-533.
    [9] Chen Y F, Lan Y P. Diode-pumped passively Q-switched Nd: YAG laser at 1123 nm [J]. Applied Physics B-Lasers and Optics, 2004, 79: 29-31. doi:  10.1007/s00340-004-1526-2
    [10] Li P, Chen X H, Zhang H N, et al. Diode-pumped passively Q-switched Nd: YAG ceramic laser at 1123 nm with a Cr4+: YAG saturable absorber [J]. Applied Physics Express, 2011, 4: 092702. doi:  10.1143/APEX.4.092702
    [11] Huang J Y, Liang H C, Su K W, et al. InGaAs quantum-well saturable absorbers for a diode-pumped passively Q-switched Nd: YAG laser at 1123 nm [J]. Applied Optics, 2007, 46(2): 239-243. doi:  10.1364/AO.46.000239
    [12] Men S J, Liu Z J, Zhang X Y, et al. A graphene passively Q-switched Nd: YAG ceramic laser at 1123 nm [J]. Laser Physics Letters, 2013, 10: 035803. doi:  10.1088/1612-2011/10/3/035803
    [13] Gao Y, Zhao T Z, Li C Y, et al. Diode-side-pumped passively Q-switched Nd: YAG laser at 1123 nm with reflective single walled carbon nanotube saturable absorber [J]. Optics Communications, 2013, 286: 261-264. doi:  10.1016/j.optcom.2012.08.045
    [14] Bai J X, Li P, Chen X H, et al. Diode-pumped passively Q-switched Nd: YAG ceramic laser with a gold nanotriangles saturable absorber at 1 µm [J]. Applied Physics Express, 2017, 10(8): 082701. doi:  10.7567/APEX.10.082701
    [15] Lin H F, Zhu W Z, Mu R Z, et al. Q-switched dual-wavelength laser at 1116 and 1123 nm using WS2 saturable absorber [J]. IEEE Photonics Technology Letters, 2018, 30(3): 285-288. doi:  10.1109/LPT.2017.2785619
    [16] 毛梦涛, 陈锦辉, 丁梓轩, 等. 基于光纤二维材料集成器件的脉冲激光器及外场调控(特邀)[J]. 红外与激光工程, 2018, 47(8): 0803003. doi:  10.3788/IRLA201847.0803003

    Mao Mengtao, Chen Jinhui, Ding Zixuan, et al. Pulsed laser based on two-dimensional material optical fiber integrated device and external control (Invited) [J]. Infrared and Laser Engineering, 2018, 47(8): 0803003. (in Chinese) doi:  10.3788/IRLA201847.0803003
    [17] Burda C, Chen X B, Narayanan R, et al. Chemistry and properties of nanocrystals of different shapes [J]. Chemical Reviews, 2005, 105(4): 1025-1102. doi:  10.1021/cr030063a
    [18] Zhang H N, Liu J. Gold nanobipyramids as saturable absorbers for passively Q-switched laser generation in the 1.1 μm region [J]. Optics Letters, 2016, 41(6): 1150-1152. doi:  10.1364/OL.41.001150
    [19] Song T, Feng C, Chen X H, et al. Gold nanorods as a saturable absorber for passively Q-switching Nd: YAG lasers at 1064.3 and 1112 nm [J]. Laser Physics Letters, 2017, 14(5): 055808. doi:  10.1088/1612-202X/aa699a
    [20] Wang L L, Chen X H, Bai J X, et al. Au nanocages/SiO2 as saturable absorbers for passively Q-switched all-solid-state laser [J]. Materials Research Express, 2018, 5(4): 045043. doi:  10.1088/2053-1591/aabe11
    [21] Wang H, Brandl D W, Nordlander P, et al. Plasmonic nanostructures: artificial molecules [J]. Accounts of Chemical Research, 2007, 40(1): 53-62. doi:  10.1021/ar0401045
    [22] Skrabalak S E, Chen J, Sun Y, et al. Gold nanocages: synthesis, properties, and applications [J]. Accounts of Chemical Research, 2008, 41(12): 1587-1595. doi:  10.1021/ar800018v
    [23] Sheik B M, Said A A, Stryland E W V. High-sensitivity, single-beam n2 measurements [J]. Optics Letters, 1989, 14(17): 955-957. doi:  10.1364/OL.14.000955
  • 加载中
通讯作者: 陈斌, bchen63@163.com
  • 1. 

    沈阳化工大学材料科学与工程学院 沈阳 110142

  1. 本站搜索
  2. 百度学术搜索
  3. 万方数据库搜索
  4. CNKI搜索

Figures(6)

Article Metrics

Article views(437) PDF downloads(27) Cited by()

Related
Proportional views

1 123 nm passively Q-switched Nd: YAG laser based on gold nanocages and MoS2 saturable absorbers

doi: 10.3788/IRLA20200084
  • 1. School of Information Science and Engineering, Shandong University, Jinan 250100, China
  • 2. Shandong Traffic Technician College, Linyi 276021, China

Abstract: Gold nanocages (GNCs) were successfully prepared by seed-mediated method and its nonlinear saturated absorption characteristic at 1123 nm was verified for the first time. As a comparison, a MoS2 saturated absorber was prepared. Based on GNCs and MoS2 as saturable absorber (SA), respectively, passively Q-switched Nd: YAG lasers at 1 123 nm were demonstrated.When Q-switched laser with MoS2 as SA, Q-switched pulse with the shortest pulse duration of 412 ns and maximum pulse repetition rate of 233 kHz was achieved under the pump power of 6.81 W with the maximum average output power of 208 mW. When Q-switched laser with GNCs as SA, Q-switched pulse with the shortest pulse duration of 253 ns and maximum pulse repetition rate of 326 kHz was achieved under the pump power of 6.04 W with the maximum average output power of 221 mW. Compared with the experimental results of MoS2 Q-switched laser, the gold nanocage Q-switched laser has higher output power and efficiency, narrower pulse width and higher repetition rate. These results indicate a great potential of the GNCs film as SA in the near-infrared region.

    • Nd:YAG晶体因其优异的光学和机械性能、易于制造、成本低等优点,依然是目前应用最广泛的固体激光介质。但其研究主要集中于946 nm、1 064 nm和1 319 nm波长的激光器上,而1 123 nm的激光发射也是一个重要的跃迁。1 123 nm激光器可作为铥上转换光纤激光器的泵浦源产生蓝色激光[1],也可通过倍频产生561 nm的黄绿光,黄绿光在医学治疗、生物荧光成像和全息存储等领域具有重要的应用价值[2]。1978年J. Marling第一次利用Nd:YAG晶体产生了1 123 nm的激光[3]。2009年S. S. Zhang等人利用Nd:YAG陶瓷作为增益介质,实现了平均输出功率为10.8 W的1 123 nm连续激光器[4]。2010年C. Y. Li等人采用侧面泵浦方式,同样用Nd:YAG陶瓷作为增益介质,将1 123 nm 连续激光器的平均输出功率提高到了219.3 W[5]。在1 123 nm调Q激光器方面,2004年Y. F. Chen等人首次采用声光调制方式实现了1 123 nm主动调Q Nd:YAG激光器[6]。2011年Y. Tang等人通过优化腔型结构,实现了1 123 nm高效率声光调Q Nd:YAG陶瓷激光器,光光转换效率高达34.2%,斜效率更是达到了39.1%[7]

      被动调Q固体激光器由于具有结构简单、成本低廉、效率高等优点,在机械加工、遥感、生物医学、军事科学等领域得到了广泛的应用[8]。饱和吸收体(SA)作为被动调Q激光器的关键,其性能直接影响激光器输出脉冲的质量。目前为止,已经应用到1 123 nm波段激光器中的饱和吸收体材料有Cr:YAG、InGaAs量子阱、石墨烯、单层碳纳米管、金纳米三角片、WS2[9-15]。近些年来,新型二维材料因其恢复时间快、工作波段宽、调制深度高、饱和吸收阈值低等优异的光学性能吸引了许多研究者的注意,被认为是一种理想的SA材料[16]。作为一个重要的代表,金纳米材料(GNPs)由于具有超快的动态载流子、灵活可调的吸收谱线和高的三阶非线性系数等特性而备受关注,并已在实验中证实了其作为SA材料的巨大潜力。众所周知,金纳米结构的物理和化学性质与它们的尺寸和形状密切相关,因此研究者可以很方便的改变它们的性能[17]。2016年,H. N. Zhang等人报道了金纳米双锥(GNBPs)为SA的全固态被动调Q激光器,在1.1 μm波段实现了脉冲宽度为396 ns、重复率为90.6 kHz的脉冲输出,获得的最大单脉冲能量为1.67 μJ [18]。2017年,T. Song等人将金纳米棒(GNRs)作为SA,设计了运行在1 064.3 nm和1 112 nm双波长的被动调Q Nd:YAG激光器,获得的最大单脉冲能量分别为0.337 μJ (1 064 nm)和1.18 μJ(1 112 nm),证明了GNRs在1.1 μm波段作为SA的能力[19]。同年J. X. Bai等人报道了基于金纳米三角片(GNTs)的分别运行在1 064 nm和1 123 nm两个波长的Nd:YAG被动调Q固体激光器,在1 123 nm波段激光器中,实现了脉冲宽度为231 ns、重复率为457 kHz的脉冲输出,获得的最大单脉冲能量分别为0.706 μJ(1 064 nm)和0.376 μJ (1 123 nm) [14]。2018年L. L. Wang等人成功制备了金纳米笼复合二氧化硅(GNCs/SiO2)饱和吸收体并实现了1 064.3 nm的Nd:YVO4被动调Q固体激光器,获得的最大单脉冲能量为0.538 μJ[20]。在这些金纳米材料中,金纳米笼(GNCs)以其独特的光电特性而受到特别关注,其立方体结构决定了它的吸收横截面积较大,同时扩大了与空气的接触面积,具有优良的散热性能和很高的损伤阈值,因此可在高功率泵浦激光器中实现稳定的脉冲输出。同时,通过改变GNCs的尺寸和外壁厚度可以很灵活地将纵向表面等离子体共振(LSPR)峰从可见光调谐到近红外区[21]

      文中成功制备了金纳米笼饱和吸收体(GNCs-SA)并首次在Nd:YAG激光器中验证了其在1123 nm处的非线性吸收特性,作为对比,同样制备了MoS2饱和吸收体(MoS2-SA)应用于同一个激光器中。在输出镜透过率为12%的激光器中,以GNCs为SA时,在最大泵浦功率6.04 W下,得到最大平均输出功率为221 mW、最窄脉冲宽度为253 ns、重复率为326 kHz的脉冲。而以MoS2为SA时,在最大泵浦功率6.81 W下,得到最大平均输出功率为208 mW、最窄脉冲宽度为412 ns、重复率为233 kHz的脉冲。

    • 实验中通过电流置换反应制备金纳米笼[22]。首先用多元醇法预制银纳米立方体溶液,取50 mL的乙二醇((CH2OH)2)和0.6 mL浓度为3 mM的硫氢化钠(NaHS)乙二醇溶液加入到烧杯中,在油浴中将其加热到150 ℃,搅拌两分钟后依次加入5 mL浓度为3 mM的盐酸(HCl)溶液和12.5 mL 浓度为20 mg/mL 的聚乙烯吡咯烷酮(PVP,分子质量约为58 000)乙二醇溶液。待混合溶液反应2 min后,注入4 mL浓度为282 mM的三氟乙酸银(C2AgF3O2)乙二醇溶液,连续搅拌90 min后,用丙酮(CH3COCH3)洗涤一次,超纯水洗涤两次就得到了银纳米立方体溶液,其透射电子显微镜(TEM)成像如图1(a)所示。接下来通过置换反应获得金纳米笼,先将100 mL浓度为1 mg/mL的PVP乙二醇溶液置于另一个烧杯中并加热至100 ℃,之后加入2 mL刚制备好的银纳米立方体溶液,静置10 min后,用注射泵以2 mL/min的流速注入20 mL浓度为0.1 mM的氯金酸(HAuCl4)溶液,待混合溶液充分反应后将其冷却至室温,然后缓慢加入1 mL的氨水(NH3·H2O)以除去反应产生的氯化银(AgCl),最后经超纯水洗涤三次后,重新将其分散到5 mL的超纯水中就得到了最终的GNCs溶液,图1(b)为GNCs的TEM成像。可看出其结构是内部中空、外壁多孔的立方体,但尺寸略有差异,经计算,其平均尺寸约为62.53 nm。利用紫外-近红外分光光度计(U4100, 185~3 300 nm)测得GNCs溶液的吸收光谱如图1(c)所示,可以看出其横向SPR峰位于可见光波段,纵向SPR峰值位于1.06 μm,同时覆盖到了实验所用的1 123 nm波长。

      Figure 1.  (a) TEM images of the silver nanocubes with a scale bar of 2.0 μm; (b) TEM image of the GNCs with a scale bar of 0.1 μm; (c) Absorption spectrum of the GNCs

      将GNCs溶液均匀涂覆到K9玻璃片上,在室温下自然风干,如此重复三次,GNCs-SA便制备完成。实验中所用的MoS2同样采用人工涂覆的方式制备出MoS2-SA薄膜。借助皮秒脉冲光纤激光器,利用开孔Z扫描的方法测量GNCs在不同光强下的透过率[23],其结果如图2所示。用指数方程$ {y}={A}_{1}\times $$ \mathrm{exp}\left(-x/{t}_{1}\right)+{y}_{0} $进行数据拟合可得GNCs-SA的调制深度A1和饱和吸收光强t1分别为5.3%和1.1 mW/cm2

      Figure 2.  Nonlinear optical properties of the as-prepared GNCs SA

    • 实验设计了一个简易的Nd:YAG激光器来研究GNCs-SA和MoS2-SA的饱和吸收性,实验装置如图3所示。谐振腔采用平凹腔设计,腔长为25 mm。泵浦源采用808 nm的光纤耦合激光二极管(LD,NA=0.22,dcore=400 μm)激光器,泵浦光通过1:1的耦合系统后聚焦到激光晶体的端面处。曲率半径为1 000 mm的平凹镜作为输入镜(M1),镜面一侧镀有对808 nm的高透膜和1 020~1 130 nm的高反膜(R>99.8%)。Nd3+掺杂浓度为1 at.%的Nd:YAG晶体作为增益介质,其形状为Φ4×10 mm3的圆柱体,晶体的两个端面均镀有对808 nm和1 123 nm的增透膜,经铟箔包裹后置于铜块内,并通过水冷系统使其温度始终维持在20 ℃。将制备好的GNCs-SA和MoS2-SA放置在尽可能靠近输出镜的地方,对1 123 nm光透过率为12%的平面镜(M2)作为耦合输出镜,同时为了防止Nd:YAG晶体跃迁谱线中其他波长的起振,M2镜面两侧均镀有对946 nm、1 064 nm和1.3 μm的增透膜(T>98%)。激光器的输出功率通过探头(Molectron, EPM10)和功率计(Molectron, EPM2000)的组合进行测量,1 GHz InGaAs探测器(New Focus)和数字示波器(Infiniiom DSO90804A, 8 GHz bandwidth, 40 G samples/s)组合用来测量脉冲的时域特性,光谱分析仪(Yokogawa, AQ6315A, 350~1 750 nm)测量激光器的输出光谱。

      首先,实验研究了没有加入SA时Nd:YAG激光器在连续运转情况下的输出特性,不同泵浦功率下的输出功率如图4(a)所示。可看出激光器阈值功率为2.06 W,随着泵浦功率增高,输出功率线性增长,光光转换效率为24.9%。输出光谱如图4(a)插图中所示,中心波长为1 123 nm,实验中没有观测到其他波长的光。

      Figure 3.  Schematic of diode-pumped GNCs-SA (MoS2) Q-switched Nd:YAG laser

      Figure 4.  Output power characteristics versus pump power of the (a) CW and (b) Q-switched Nd:YAG lasers. Inset of (a): Emission spectrum

      随后分别将MoS2-SA和GNCs-SA插入到谐振腔中研究Nd:YAG被动调Q激光器的输出特性,图4(b)为输出功率随泵浦功率变化的关系图。当MoS2作为饱和吸收体时,调Q激光器的阈值功率为2.73 W,获得的最大输出功率为208 mW,此时泵浦功率为6.81 W,对应的光光转换效率和斜效率分别为3%和5.1%。而当GNCs作为饱和吸收体时,调Q激光器阈值为2.61 W,泵浦功率达到6.04 W时获得最大输出功率221 mW,相应的光光转换效率和斜效率分别为3.6%和6.4%。由于插入饱和吸收体引入了较大的损耗,所以调Q激光器相较于连续激光器的阈值功率升高,效率也随之减小。而将两种饱和吸收体对比来看,GNCs-SA相较于MoS2-SA阈值功率更低,且效率更高,因此更具优势。

      调Q激光器输出脉冲的脉冲宽度和重复率随泵浦功率的变化情况如图5所示。对于两种不同的SA材料,脉冲宽度均随着泵浦功率的增大而减小,而脉冲重复率增大,符合典型的被动调Q特征。当MoS2作为饱和吸收体时,随着泵浦功率从3.08 W增加到6.81 W,脉冲宽度由971 ns减小到412 ns,而重复率由85 kHz增加到233 kHz。泵浦功率达到6.81 W时,得到最短的脉冲宽度为412 ns,最大脉冲重复率为233 kHz,此时的单脉冲波形和脉冲序列如图6(a)所示。此时获得的最大单脉冲能量为0.892 μJ,最高峰值功率为2.12 W。而当GNCs作为饱和吸收体时,随着泵浦功率从2.97 W增加到6.04 W,脉冲宽度从623 ns减小到253 ns,而重复率由138 kHz增加到326 kHz。泵浦功率达到6.04 W时,得到最短的脉冲宽度为253 ns,最大脉冲重复率为326 kHz,此时的单脉冲波形和脉冲序列如图6(b)所示。当泵浦功率为5.79 W时,获得的最大单脉冲能量为0.723 μJ,当泵浦功率为6.04 W时,获得的最高峰值功率为2.68 W。GNCs-SA相较于MoS2-SA,获得的脉冲宽度更窄,脉冲重复率更高,因此更适合用于饱和吸收体。

      Figure 5.  Change of pulse repetition rate and pulse width versus pump power at (a) MoS2-SA and (b) GNCs-SA

      Figure 6.  Single pulse profiles and pulse trains of (a) MoS2-SA and (b) GNCs-SA Q-switched Nd:YAG lasers

    • 实验成功制备了金纳米笼饱和吸收体并首次将其应用于1 123 nm波段Nd:YAG被动调Q激光器中,同时制备了MoS2饱和吸收体作为对比。在输出镜透过率为12%的Nd:YAG激光器中,当MoS2作为饱和吸收体时,获得的最大平均输出功率为208 mW,最短脉冲宽度412 ns,对应的重复频率233 kHz;在GNCs作为饱和吸收体的调Q激光器中,获得的最大平均输出功率为221 mW,最短脉冲宽度253 ns,对应的重复率为326 kHz。实验结果证明了金纳米笼相较于MoS2在1.1 μm波段激光器中具有更好的饱和吸收特性,是一种极具潜力的饱和吸收材料。

Reference (23)

Catalog

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return
    Return