紫外与近红外超快激光诱导等离子体通道特性的比较研究
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摘要
超快激光等离子通道(光丝)的产生和传输在过去的十几年中成为了一个热门问题。在近红外飞秒光丝方面的研究取得了令人瞩目的成果,尤其超连续谱、光丝自压缩、多光子电离、锥状辐射等,为获得周期量级的超短脉冲提供了可能。而迄今为止,对于超快脉冲激光成丝的研究基本上是在红外光谱范围内进行的。由于紫外激光成丝阈值低,聚焦性能优越,所以研究紫外激光的成丝特性成为了目前超快激光领域有特色的研究。
本论文利用mJ级紫外飞秒激光脉冲光源,研究其光谱、丝长、成丝位置、丝径、能量透过率和成丝阈值等特性,并与近红外飞秒激光成丝特性相比较,进一步验证发展紫外强场光物理的潜在优势,并为开展紫外强场等离子体通道的光谱研究提供有参考价值的数据,这是本论文的主要目标。
本人进行了以下实验工作：
1、采用了倍频-补偿-和频的共线结构实现晶体中飞秒脉冲的高效谐波转换,优化了其中的相位失配、群速度失配等参数,使三次谐波的转换效率可达到10%,实现了紫外飞秒激光毫焦量级的输出,峰值功率达到10GW级,为进一步研究紫外脉冲激光成丝的实验研究提供了必要条件。
2、利用紫外飞秒激光在不同焦距下聚焦产生等离子体通道,重点研究了紫外光丝的成丝特性,包括光丝在成丝前后的光谱变化、成丝长度和成丝位置、丝的直径、能量透过率和成丝阈值等特性,并获得了成丝阈值条件等重要参数。
3、通过对近红外激光的成丝特性的补充测量,重点作了紫外和近红外等离子体通道特性的比较和分析。
通过实验结果比较得出了以下结论：紫外和近红外激光都有频谱展宽效应；紫外等离子体光丝的成丝阈值明显低于近红外一个量级,聚焦能力也强于近红外；紫外等离子体通道的传输距离比近红外更长等结果。
Over the years, the propagation of femtosecond filament in transparent media has attracted considerable attentions. Filamentation in the near-infrared (IR) femtosecond pulse has achieved numerous excellent results, such as the generation of super-continuum from ultraviolet (UV) to IR, multiphoton ionization and conical emission, etc. the pulse self-compression due to filamentation provides the possibility for generation of few-cycle pulse. The UV femtosecond laser pulse has numerous outstanding optical features, such as excellent focus ability, high single photon energy, large ionization rate, and so forth. It is nevertheless somehow difficult to generate high-intensity UV fs pulses, and due to the lack of suitable UV fs sources, researches on UV femtosecond filaments are not as prevailing as those on near-IR filaments.
In this thesis, the characterics of spectra, length, filamentation position, diameter, energy transmission and threshold by mJ-level UV femtosecond laser pulse are demonstrated. Compared to the properties of IR femtosecond filamentation, the potential values for developing the strong UV laser pulse are proposed. The main aim of this paper is to provide valuable data for the plasma spectroscopy of ultrafast UV laser.
This thesis consists of three parts:
1. An approach of frequency doubling-compensation-tripling in collinear structure for femtosecond pulses was designed and employed to fulfill efficient harmonic conversion,optimized the phase and group velocity mismatch and improves the conversion efficiency of third frnquency harmonic, so as to get the level of 10%. We realized the third frequency harmonic of mj and produced the peak power of 10GW lever. This provides the prerequisite for the study of ultrafast UV plasma filaments.
2. We focused on the plasma filaments properties of UV in different focal length, such as the spectral change, length,position,diameter, energy change and threshold of plasma filaments,and got into the important parameters of threshold condition.
3. The thesis measured characteristics of near-infrared plasma filaments, then make a comparative analysis about UV and infrared plasma filaments. Through experiment we have concluded the following conclusion:the VU and near-infrared plasma filaments have shown that Spectrum broadening effect; The self-focusing threshold of UV pulse is one order of magnitude lower than that of IR pulse. The focusing ability of UV pulse is more excellent than IR. The filaments length of UV pulse is longer than IR.
本论文利用mJ级紫外飞秒激光脉冲光源,研究其光谱、丝长、成丝位置、丝径、能量透过率和成丝阈值等特性,并与近红外飞秒激光成丝特性相比较,进一步验证发展紫外强场光物理的潜在优势,并为开展紫外强场等离子体通道的光谱研究提供有参考价值的数据,这是本论文的主要目标。
本人进行了以下实验工作：
1、采用了倍频-补偿-和频的共线结构实现晶体中飞秒脉冲的高效谐波转换,优化了其中的相位失配、群速度失配等参数,使三次谐波的转换效率可达到10%,实现了紫外飞秒激光毫焦量级的输出,峰值功率达到10GW级,为进一步研究紫外脉冲激光成丝的实验研究提供了必要条件。
2、利用紫外飞秒激光在不同焦距下聚焦产生等离子体通道,重点研究了紫外光丝的成丝特性,包括光丝在成丝前后的光谱变化、成丝长度和成丝位置、丝的直径、能量透过率和成丝阈值等特性,并获得了成丝阈值条件等重要参数。
3、通过对近红外激光的成丝特性的补充测量,重点作了紫外和近红外等离子体通道特性的比较和分析。
通过实验结果比较得出了以下结论：紫外和近红外激光都有频谱展宽效应；紫外等离子体光丝的成丝阈值明显低于近红外一个量级,聚焦能力也强于近红外；紫外等离子体通道的传输距离比近红外更长等结果。
Over the years, the propagation of femtosecond filament in transparent media has attracted considerable attentions. Filamentation in the near-infrared (IR) femtosecond pulse has achieved numerous excellent results, such as the generation of super-continuum from ultraviolet (UV) to IR, multiphoton ionization and conical emission, etc. the pulse self-compression due to filamentation provides the possibility for generation of few-cycle pulse. The UV femtosecond laser pulse has numerous outstanding optical features, such as excellent focus ability, high single photon energy, large ionization rate, and so forth. It is nevertheless somehow difficult to generate high-intensity UV fs pulses, and due to the lack of suitable UV fs sources, researches on UV femtosecond filaments are not as prevailing as those on near-IR filaments.
In this thesis, the characterics of spectra, length, filamentation position, diameter, energy transmission and threshold by mJ-level UV femtosecond laser pulse are demonstrated. Compared to the properties of IR femtosecond filamentation, the potential values for developing the strong UV laser pulse are proposed. The main aim of this paper is to provide valuable data for the plasma spectroscopy of ultrafast UV laser.
This thesis consists of three parts:
1. An approach of frequency doubling-compensation-tripling in collinear structure for femtosecond pulses was designed and employed to fulfill efficient harmonic conversion,optimized the phase and group velocity mismatch and improves the conversion efficiency of third frnquency harmonic, so as to get the level of 10%. We realized the third frequency harmonic of mj and produced the peak power of 10GW lever. This provides the prerequisite for the study of ultrafast UV plasma filaments.
2. We focused on the plasma filaments properties of UV in different focal length, such as the spectral change, length,position,diameter, energy change and threshold of plasma filaments,and got into the important parameters of threshold condition.
3. The thesis measured characteristics of near-infrared plasma filaments, then make a comparative analysis about UV and infrared plasma filaments. Through experiment we have concluded the following conclusion:the VU and near-infrared plasma filaments have shown that Spectrum broadening effect; The self-focusing threshold of UV pulse is one order of magnitude lower than that of IR pulse. The focusing ability of UV pulse is more excellent than IR. The filaments length of UV pulse is longer than IR.
引文
[1]韩海年,魏志义,苍宇.阿秒激光脉冲的新进展[J].物理,2003,32(11)：762-765.
[2]S.L.chin, A.Brodeur, S.Petit, O.G.Kosareva, and V.P.Kandidov, "Filamentation and supercontinuum generation during the propagation of powerful ultrashort laser pulses in optical media(white light laser), " J.Non.Opt.Phys.8 121(1999).
[3]Nibbering, E.T.J, Curley P.F, Grillon.G, et al. "Conical emission from self-guided femtosecond pulses in air, " Opt.Lett,1996,21(1):62～64.
[4]A.Braun, G.Korn, X.Liu, D.Du, J.Squier, and G.Mourou, "Self-channeling of high-peak-power femtosecond laser pulses in air, " Opt.Lett.20,73(1995).
[5]D.E.Spence, P.N.Kean, W.sibbett, Opt.Lett.16,42(1991).
[6]D. Strickland, G. Mourous, Opt. Commun.,56,219,1985.
[7]A. Dubietis, G. Jonusauskas, A. Piskarskas:Powerful femtosecond pulse generation by chirped and stretched pulse parametric amplification in BBO crystal, Opt. Commun.,88,437(1992)
[8]A. becker, N. akozbek2,K. vijayalakshmi, E. orall, C.M. Bowden,S.L. chin, Intensity clamping and re-focusing of intense femtosecond laser pulses in nitrogen molecular gas, Appl. Phys. B 73,287-290 (2001).
[9]A.Brodeur,C.Y.Chien,F.A.Ilkov,S.L.Chin,O.G.Kosareva,andV.P.Kandidov,"Movi ng focus in the propagation of ultrashort laser pulses inair,"Opt.Lett.22,304(1997).
[10]L. Woste, C. Wedekind, H. Wille, P. Rairoux, B. Stein, S. Nikolov, Chr. Werner.S.Nidermeier, F. Ronneberger, H. Schillinger, and R. Sauerbrey, Laser Optoelectron.29,51 (1997).
[11]W.Watanabe.and K.Itoh,"Spatial coherence of supercontinuum emitted from multiple filaments,"Jpn.J.Appl.Phys.40 592(2001).
[1]S.Tzortzakis,L.Berge,A.Couairon,M.Franco,B.Prade,and A.Mysyrowicz，"Breakup and fusion of self-guided femtosecond light pulses in air,"Phys.Rev.Lett.86 5470(2001).
[2]S.L.Chin,A.Brodeur,S.Petit,O.G.Kosareva,V.P.Kandidov,J.Nonl.Opt.Phys.Mater.81, 121(1999).
[3]郝光生,刘颂豪,强光光学浅说,科学出版社,68～73,1987.
[4]蓝信钜,激光技术,科学出版社,126～128,2000.
[5]J. H. Marburger, in Progress in Quantum Electronics,J. H. Saunders and S. Stenholm, eds. (Pergamon,Oxford,1975), Vol.4, pp.35-110.
[6]A. Couairon and L. Berge, Light Filaments in Air for Ultraviolet and Infrared Wavelengths, Phys.Rev.Lett.,88,13(2002).
[7]A.Brodeur,C.Y.Chien,F.A.Ilkov,S.L.Chin,O.G.Kosareva,and V.P.Kandidov,"Moving focus in the propagation of ultrashort laser pulses in air,"Opt.Lett.22,304(1997).
[8]沈元壤.非线性光学原理(上册).北京：科学出版社,1987.337
[9]H.D.Ladouceur,A.P.Baronavski,D.Lohumann,P.W. Grounds,andP.G.Girardi, "Electrical conductivity of a femtosecond laser generated plasma channel in air,"Opt.Comm.189 107(2001).
[10]Corkum P B,"Amplification of picosecond 10μm pulses inmultiatmosphere CO2, Lasers, "IEEE J.Quantum Electron.21 216(1985).
[11]Rae S C,"Spectral blueshifting and spatial defocusing of intense laser pulses in dense gases,"Opt.Comm.104330(1994).
[12]M.Mlejmek,E.M.Wright,and J.V.Moloney,"Dynamic spatial replenishment of femtosecond pulses propagating in air,"Opt.Lett.23 382(1998).
[13]P.B.Corkum et al,Opt.Lett.10,624(1985).
[14]A.Brodeur and S.L.Chin,Phys.Rhys.Rev.Lett.80,4406(1998).
[15]A.Brodeur and S.L.Chin,J.Opt.Soc.Am.B 16,637(1999).
[16]Jiansheng Liu,H.schroeder,S.LChin,Ruxin Li,and Zhizhan Xu, Nonlinear propagation of fs laser pulses in liquids and evolution of supercontinuum generation,Opt.Expr,13,25,2005.
[17]P.B.Corkum et al.,Phys.Rev.Lett.57,2268(1986).
[18]J.H.Glownia et al.,J.Opt.Soc.Am.B 3,1573(1986).
[19]V.Francios et al.,Opt.Commun.99,241(1993).
[20]S.L.Chin,S.Petit,W.Liu,A.Iwasaki,M.-C.Nadeau,V.P.Kandidov,O.G.Kosareva,and K.Yu,Andrianov,"Interference of transverse rings in multifilamentation of powerful femtosecond laser pulses in air,"Opt.Comm.210,329-341 (2002).
[21]I.Golub, " Optical characteristics of supercontinuum generation, Opt.Lett.15,305(1990)
[1]王燕玲,紫外超快激光产生及其光丝效应,华东师范大学(2009)
[2]Backus.S, Peatross.J, Zeek.E, Read.K, Kapteyn.H, Murnane.M.M, "Sub-20-fs pulse generation in the ultraviolet" Conference Proceedings-Lasers and Electro-Optics Society Annual Meeting-LEOS 469 1996.
[3]刘运全,张杰,梁文锡,王兆华“飞秒掺钛蓝宝石激光三倍频理论和实验研究”物理学报54,1593(2005)
[4]Li Keyu, Li Kun, Zeng Xiaoming, Gu Yiqiu, Hang Wei, et al., "The Art for broad-bandwidth direct third-harmonic generation focusing beams in a single crystal of BBO", Proceedings of SPIE-The International Society for Optical Engineering 6839 Nonlinear Optics:Technologies and Applications,2008.
[5]刁煦,李琨,张彬等,“高强度超短脉冲单块BBO晶体的三倍频研究”,光电工程35,115(2008)
[6]蓝信钜,激光技术,科学出版社,226-228,2000.
[7]蓝信钜,激光技术,科学出版社,232-234,2000.
[8]戴小民,超快紫外激光脉冲测量诊断的研究,华东师范大学,2010.
[1]李海宁,基于超快激光放大系统的啁啾效应控制,华东师范大学,2006.
[2]Wangyanlin, ZhouXu gui, et al, " Efficient collinear frequency tripling of femtosecond laser with compensation of group velocity delay ", ChinesePhysiesB,10:34,2009.
[3]Gadi Fibich, Shmuel Eisenmann, Boaz Ilan, Arie Zigler, Control of multiple filamentation in air, Opt. Lett.29,15,2004.
[4]P. Maioli, R. Salame, N. Lascoux, E. Salmon, P. Bejot, J. Kasparian,and J.-P. Wolf, Ultraviolet-visible conical emission by multiple laser filaments
[5]P Sprangle,J.R.Penano,and B.Hafizi"Propagation of intense short laser pulses in the atmosphere,"Phys.Rev.E.66 046418,2002.
[6]H.Nishioka,W.Odajima,K.Ueda,and H.Takuma,"Ultrabroadband flat continuum generation in multichannel propagation of terrawatt Ti:sapphire laser pulses,"Opt.Lett.20 2505,1995.
[7]J.Kasparian,J.Solle,M.Richard,and J.-P. Wolf:Ray-tracing simulation of ionization-free filamentation,Appl.Phys.B 79 947,2004.
[8]王淦昌,人造小太阳：受控惯性约束聚变,清华大学出版社,2000.
[9]杨辉,全固化腔倒空激光器和超短激光脉冲在大气中传播,中科院物理所博士论文,2004.
[10]Gadi Fibich, Shmuel Eisenmann, Boaz Ilan, Yossi Erlich, Moshe Fraenkel, Zohar Henis, Alexander L. Gaeta and Arie Zigler, Self-focusing distance of very high power laser pulses, Opt.Expr.13,15,2005.
[2]S.L.chin, A.Brodeur, S.Petit, O.G.Kosareva, and V.P.Kandidov, "Filamentation and supercontinuum generation during the propagation of powerful ultrashort laser pulses in optical media(white light laser), " J.Non.Opt.Phys.8 121(1999).
[3]Nibbering, E.T.J, Curley P.F, Grillon.G, et al. "Conical emission from self-guided femtosecond pulses in air, " Opt.Lett,1996,21(1):62～64.
[4]A.Braun, G.Korn, X.Liu, D.Du, J.Squier, and G.Mourou, "Self-channeling of high-peak-power femtosecond laser pulses in air, " Opt.Lett.20,73(1995).
[5]D.E.Spence, P.N.Kean, W.sibbett, Opt.Lett.16,42(1991).
[6]D. Strickland, G. Mourous, Opt. Commun.,56,219,1985.
[7]A. Dubietis, G. Jonusauskas, A. Piskarskas:Powerful femtosecond pulse generation by chirped and stretched pulse parametric amplification in BBO crystal, Opt. Commun.,88,437(1992)
[8]A. becker, N. akozbek2,K. vijayalakshmi, E. orall, C.M. Bowden,S.L. chin, Intensity clamping and re-focusing of intense femtosecond laser pulses in nitrogen molecular gas, Appl. Phys. B 73,287-290 (2001).
[9]A.Brodeur,C.Y.Chien,F.A.Ilkov,S.L.Chin,O.G.Kosareva,andV.P.Kandidov,"Movi ng focus in the propagation of ultrashort laser pulses inair,"Opt.Lett.22,304(1997).
[10]L. Woste, C. Wedekind, H. Wille, P. Rairoux, B. Stein, S. Nikolov, Chr. Werner.S.Nidermeier, F. Ronneberger, H. Schillinger, and R. Sauerbrey, Laser Optoelectron.29,51 (1997).
[11]W.Watanabe.and K.Itoh,"Spatial coherence of supercontinuum emitted from multiple filaments,"Jpn.J.Appl.Phys.40 592(2001).
[1]S.Tzortzakis,L.Berge,A.Couairon,M.Franco,B.Prade,and A.Mysyrowicz，"Breakup and fusion of self-guided femtosecond light pulses in air,"Phys.Rev.Lett.86 5470(2001).
[2]S.L.Chin,A.Brodeur,S.Petit,O.G.Kosareva,V.P.Kandidov,J.Nonl.Opt.Phys.Mater.81, 121(1999).
[3]郝光生,刘颂豪,强光光学浅说,科学出版社,68～73,1987.
[4]蓝信钜,激光技术,科学出版社,126～128,2000.
[5]J. H. Marburger, in Progress in Quantum Electronics,J. H. Saunders and S. Stenholm, eds. (Pergamon,Oxford,1975), Vol.4, pp.35-110.
[6]A. Couairon and L. Berge, Light Filaments in Air for Ultraviolet and Infrared Wavelengths, Phys.Rev.Lett.,88,13(2002).
[7]A.Brodeur,C.Y.Chien,F.A.Ilkov,S.L.Chin,O.G.Kosareva,and V.P.Kandidov,"Moving focus in the propagation of ultrashort laser pulses in air,"Opt.Lett.22,304(1997).
[8]沈元壤.非线性光学原理(上册).北京：科学出版社,1987.337
[9]H.D.Ladouceur,A.P.Baronavski,D.Lohumann,P.W. Grounds,andP.G.Girardi, "Electrical conductivity of a femtosecond laser generated plasma channel in air,"Opt.Comm.189 107(2001).
[10]Corkum P B,"Amplification of picosecond 10μm pulses inmultiatmosphere CO2, Lasers, "IEEE J.Quantum Electron.21 216(1985).
[11]Rae S C,"Spectral blueshifting and spatial defocusing of intense laser pulses in dense gases,"Opt.Comm.104330(1994).
[12]M.Mlejmek,E.M.Wright,and J.V.Moloney,"Dynamic spatial replenishment of femtosecond pulses propagating in air,"Opt.Lett.23 382(1998).
[13]P.B.Corkum et al,Opt.Lett.10,624(1985).
[14]A.Brodeur and S.L.Chin,Phys.Rhys.Rev.Lett.80,4406(1998).
[15]A.Brodeur and S.L.Chin,J.Opt.Soc.Am.B 16,637(1999).
[16]Jiansheng Liu,H.schroeder,S.LChin,Ruxin Li,and Zhizhan Xu, Nonlinear propagation of fs laser pulses in liquids and evolution of supercontinuum generation,Opt.Expr,13,25,2005.
[17]P.B.Corkum et al.,Phys.Rev.Lett.57,2268(1986).
[18]J.H.Glownia et al.,J.Opt.Soc.Am.B 3,1573(1986).
[19]V.Francios et al.,Opt.Commun.99,241(1993).
[20]S.L.Chin,S.Petit,W.Liu,A.Iwasaki,M.-C.Nadeau,V.P.Kandidov,O.G.Kosareva,and K.Yu,Andrianov,"Interference of transverse rings in multifilamentation of powerful femtosecond laser pulses in air,"Opt.Comm.210,329-341 (2002).
[21]I.Golub, " Optical characteristics of supercontinuum generation, Opt.Lett.15,305(1990)
[1]王燕玲,紫外超快激光产生及其光丝效应,华东师范大学(2009)
[2]Backus.S, Peatross.J, Zeek.E, Read.K, Kapteyn.H, Murnane.M.M, "Sub-20-fs pulse generation in the ultraviolet" Conference Proceedings-Lasers and Electro-Optics Society Annual Meeting-LEOS 469 1996.
[3]刘运全,张杰,梁文锡,王兆华“飞秒掺钛蓝宝石激光三倍频理论和实验研究”物理学报54,1593(2005)
[4]Li Keyu, Li Kun, Zeng Xiaoming, Gu Yiqiu, Hang Wei, et al., "The Art for broad-bandwidth direct third-harmonic generation focusing beams in a single crystal of BBO", Proceedings of SPIE-The International Society for Optical Engineering 6839 Nonlinear Optics:Technologies and Applications,2008.
[5]刁煦,李琨,张彬等,“高强度超短脉冲单块BBO晶体的三倍频研究”,光电工程35,115(2008)
[6]蓝信钜,激光技术,科学出版社,226-228,2000.
[7]蓝信钜,激光技术,科学出版社,232-234,2000.
[8]戴小民,超快紫外激光脉冲测量诊断的研究,华东师范大学,2010.
[1]李海宁,基于超快激光放大系统的啁啾效应控制,华东师范大学,2006.
[2]Wangyanlin, ZhouXu gui, et al, " Efficient collinear frequency tripling of femtosecond laser with compensation of group velocity delay ", ChinesePhysiesB,10:34,2009.
[3]Gadi Fibich, Shmuel Eisenmann, Boaz Ilan, Arie Zigler, Control of multiple filamentation in air, Opt. Lett.29,15,2004.
[4]P. Maioli, R. Salame, N. Lascoux, E. Salmon, P. Bejot, J. Kasparian,and J.-P. Wolf, Ultraviolet-visible conical emission by multiple laser filaments
[5]P Sprangle,J.R.Penano,and B.Hafizi"Propagation of intense short laser pulses in the atmosphere,"Phys.Rev.E.66 046418,2002.
[6]H.Nishioka,W.Odajima,K.Ueda,and H.Takuma,"Ultrabroadband flat continuum generation in multichannel propagation of terrawatt Ti:sapphire laser pulses,"Opt.Lett.20 2505,1995.
[7]J.Kasparian,J.Solle,M.Richard,and J.-P. Wolf:Ray-tracing simulation of ionization-free filamentation,Appl.Phys.B 79 947,2004.
[8]王淦昌,人造小太阳：受控惯性约束聚变,清华大学出版社,2000.
[9]杨辉,全固化腔倒空激光器和超短激光脉冲在大气中传播,中科院物理所博士论文,2004.
[10]Gadi Fibich, Shmuel Eisenmann, Boaz Ilan, Yossi Erlich, Moshe Fraenkel, Zohar Henis, Alexander L. Gaeta and Arie Zigler, Self-focusing distance of very high power laser pulses, Opt.Expr.13,15,2005.