This work was supported by the Japan Science and Technology Agency (JST) through the Strategic Innovation Program. KPN acknowledges support from a grant-in-aid for scientific research (Grant no. 15H05462) from the Japan Society for the Promotion of Science (JSPS).

注意:戴上防护眼镜，并严格避免直接暴露于紫外线灯管和所有的激光器，包括飞秒激光。穿无尘室西装，手套，以避免污染。妥善处理任何纤维垃圾在指定的垃圾箱。 1.纳米纤维制备方法<ol><li>使用纤维涂层剥离剥离单模光纤的聚合物护套在由200毫米分离的两个地方一个5毫米的长度。使用清洁的洁净室两个机械剥离部分蘸抹在甲醇。浸在丙酮中这两个剥离部分之间的光纤。等待10 - 15分钟，直到纤维的外套土崩瓦解。取出丙酮纤维和洁净室用蘸抹在甲醇清洁整个剥离一部分。 </li><li>上设置光学纳米纤维制造设备（ONME）的两个阶段的剥离的纤维来制造纳米纤维。 <ol><li>发射探头激光到光纤和监测transmissioN使用光电二极管和使用ADC卡记录在计算机中的传输数据。开始使用ONME软件气流和点燃火焰。装载在ONME软件的预先优化参数为锥形纤维的具有500纳米的束腰直径的制造，并开始制造过程。 注:ONME是市售装置，设计用来制造使用标准热量和拉技术锥形光纤。它使用氢氧焰加热纤维和两个电动平台拉纤。气流和阶段的动作是由计算机程序控制。预优化的参数可以从供应商处获得，根据特殊要求。 </li></ol></li><li>在制造之后，赶上锥形光纤到使用UV可固化环氧树脂的纳米纤维支架。涵盖使用具有玻璃板顶盖（在图1a示出）的纳米纤维支架。把样品清洁箱内并传送到飞秒拉SER制造单位。 </li></ol> 2.飞秒激光制作<ol><li>制造安装的对齐<ol><li>把制造长凳上的玻璃板在15毫米的高度。 1兆焦耳的脉冲能量照射5秒的飞秒激光。识别飞秒激光从白色光产生致烧蚀和烧蚀图案的外观上的玻璃板损伤线。 </li><li>通过改变使用的制造工作台的X台的玻璃板的高度重复此过程。对于每一个制造，1毫米的翻译是在制造工作台的Y台使制造中的新位置。 </li><li>查找最强的消融线的高度。在这个位置上，微调折转镜中的一个的倾斜角度和位置以最大化消融。此外，微调制造工作台的X台的倾斜，以最大限度地消融。 注:在折叠式反射镜的倾斜角度被调谐USI纳克运动反射镜支架调谐旋钮和反射镜的位置是由翻译在其上被安装在Z阶段调整。 </li><li>优化后，标记的CCD照相机软件的消融线的位置，并移除玻璃板。 注:CCD摄像机的控制软件使图像捕捉和图纸标记所拍摄的图像上。它还使保存所捕获的图像和所述记号的数据。由于制造工作台的X台不具有绝对位置的参考，在CCD图像被用作在X轴的位置的参考。 CCD图象的分辨率为每像素10微米。 </li><li>使用铂（Pt）-coater，涂层60秒的玻璃板在玻璃板沉积Pt形成的25nm的层。图像使用扫描电子显微镜（SEM）在玻璃板的烧蚀图案。如果消融图案示出了具有周期为350nm（预期的干涉条纹图案），则人的周期性结构ignment优化。否则重复该过程（从步骤2.1.1 - 2.1.4）较低的脉冲能量（低至300μJ），直到周期性烧蚀图案能够被看见。 </li></ol></li><li>变迹腔光子晶体的制备<ol><li>放置制造长凳大致平行于标记在CCD相机上的消融线在锥形纤维。 </li><li>通过锥形光纤发送的探针激光（功率= 1毫瓦），并从CCD相机上的锥形光纤观察散射。最强的散射部分相对应的纳米纤维区域，由于其亚波长直径。 </li><li>翻译的制造长凳的Z阶段到纳米纤维中心到标在CCD相机上的消融线的位置。 </li><li>关闭探测激光照射，并以最小的脉冲能量（&lt;10μJ）飞秒激光。翻译是Y台重叠与飞秒激光束的纳米纤维。该重叠是由纳米纤维，观测的照度确定的erved CCD摄像机上。 注:纳米纤维是现在相对于沿Y上的飞秒激光束和Z轴对准。 </li><li>为了对准沿X轴的纳米纤维，翻译的X阶段重叠纳米纤维位置到消融线位置标记的CCD照相机上。 </li><li>翻译Y台最大化纳米纤维的重叠与飞秒激光。从纳米纤维观察两个第一订单的反射（出现在顶盖的玻璃板两大亮点）。观察这些反射点的运动，而平移Y台来回。 注:如果这些斑点朝向一侧移动，然后纳米纤维是不平行于消融线。在这种情况下，旋转旋转台以使平行于消融线的纳米纤维。当它们是平行的，所述反射斑出现作为闪光灯。 </li><li>使平行的纳米纤维到消融线之后，翻译Y台以最大化飞秒激光束和纳米纤维之间重叠，通过测量飞秒激光散成使用光电二极管在锥形光纤的端部的纳米纤维引导模式的功率。最大化重叠后，旋转旋转台来制造θ= 0.5度的角度。 注:对于飞秒激光和纳米纤维之间的最大重叠，人们会期望零落成纳米纤维导模飞秒激光的功率最大化。 </li><li>封锁功率计飞秒激光和脉冲能量设置为0.27兆焦耳。改变飞秒激光设置以单次照射模式。 注意:在此模式下，当按下火开关只产生一个单一的脉冲，否则没有激光输出。 <ol><li>除去从激光束路径中的功率计和火单个飞秒激光脉冲。这样就完成了制造工艺。 </li></ol></li></ol></li><li> Fabricati上缺陷引起的光子晶体腔<ol><li>通过如第2.1节所述观察在玻璃板上消融检查设置的对齐方式。发现为最强消融线的高度之后，就在相掩模之前插入在激光束的中心0.5mm的铜线。铜线应沿Y轴（垂直于消融线）。 </li><li>检查烧蚀图案在玻璃板上，同时改变沿Z轴的铜线的位置。固定铜线的位置时，烧蚀图案示出在消融线的中心的单个缺口。 </li><li>在对准之后，对下列中的第2.2节详细说明的方法的纳米纤维进行飞秒激光加工。对于该制造，设置制造的角度θ= 0度。 </li></ol></li></ol> 3.制作的试样的表征<ol><li>光学特性的测定<ol><li>准备SE和设定为如图1b所示的光学测量。发射宽带光源到锥形光纤之前和使用频谱分析仪的制造之后测量透射和反射光谱。制造之后，透射光谱将显示对应于所制造的样品的布拉格共振的阻带。 </li><li>旋转光纤在线偏振器的拨片来选择极化，并采取光谱两个正交偏振的x-pol和Y-POL。 注:对于X-POL（极化沿着纳米环形山）阻带将是蓝移21（朝较短波长）和纳米纤维的散射会更强。所以，通过观察光谱和CCD摄像机选择偏振。 </li><li>对于偏振之一，通过拉伸使用PZT（ 图1b所示）的锥形光纤采取透射光谱。采取由s谱tretching在2微米的步骤锥形纤维直到20微米的最大拉伸长度（由PZT扫描范围的限制）。观察到布拉格共振会红移通过拉伸锥形纤维（朝向较长波长）。从这些光谱，计算的布拉格共振的拉伸长度的移位，每单位。 </li><li>为解决腔模式并测量绝对空腔传输，使用可调谐CW激光器源。发射激光到锥形光纤和使用光电二极管监测传输。 </li><li>设置激光波长的阻带为Y型聚合酶的红色侧缘，并使用纤维内联偏振器，以尽量减少传输。以这种方式，在X-POL分量被抑制，只选择在Y-POL。设置激光波长进一步出红色侧带边的，并记录传输，同时从0伸展锥形纤维 - 20微米。 <ol><li>通过改变激光沃维勒重复测量ength蓝侧中的0.3纳米的步骤，直到整个阻带覆盖。从这些数据，重建使用数据在步骤3.1.3测定每单位拉伸长度的谐振移位的整个频谱。 注:对于与空腔的模式转变由2纳米通过20微米，典型的自由光谱范围的腔模式之间0.05拉伸锥形光纤沿一个典型样品，阻带（布拉格共振） - 纳米0.5。对于输入激光的一个给定的波长可以测量至少3 - 通过拉伸锥形光纤4的腔模式。模式之间的频率间隔是从在步骤3.1.3测定每单位拉伸长度的谐振移位数据推断。通过改变在0.3纳米步激光波长，至少2重复测量 - 连续3个腔模式在连续测量重新测量。可以通过叠加在传输数据的同时垫上的连续测量重建整个频谱重新测量腔模的清地位。 </li></ol></li><li>现在测量使用类似的操作，在步骤3.1.5和3.1.5.1中提到的其他偏振的频谱。 </li></ol></li><li>成像样品制备<ol><li>把在2厘米长的金属板的制造样品和使用UV可固化环氧树脂的锥形光纤的两端固定于金属板。确保样品的照射侧面的金属板，使得阴影侧能够被成像。 </li><li>使用铂涂布机涂覆样品30秒，并用厚度10nm左右的沉积铂的层。将样品放入SEM表示。取样品的SEM图像在每个0.1毫米在整个制作区域。 </li></ol></li></ol>

<ol>
	<li>Painter, O. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-Dimensional+Photonic+Band-Gap+Defect+Mode+Laser.">Two-Dimensional Photonic Band-Gap Defect Mode Laser.</a> Science. 284, 1819-1821 (1999).</li><li>Loncar, M., Scherer, A., Qiu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photonic+crystal+laser+sources+for+chemical+detection.">Photonic crystal laser sources for chemical detection.</a> Appl. Phys. Lett. 82, 4648 (2003).</li><li>Tanabe, T., Notomi, M., Mitsugi, S., Shinya, A., Kuramochi, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=All-optical+switches+on+a+silicon+chip+realized+using+photonic+crystal+nanocavities.">All-optical switches on a silicon chip realized using photonic crystal nanocavities.</a> Appl. Phys. Lett. 87, 151112 (2005).</li><li>Yoshie, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vacuum+Rabi+splitting+with+a+single+quantum+dot+in+a+photonic+crystal+nanocavity.">Vacuum Rabi splitting with a single quantum dot in a photonic crystal nanocavity.</a> Nature. 432, 200-203 (2004).</li><li>Akimov, A. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+single+optical+plasmons+in+metallic+nanowires+coupled+to+quantum+dots.">Generation of single optical plasmons in metallic nanowires coupled to quantum dots.</a> Nature. 450, 402-406 (2007).</li><li>Noginov, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Demonstration+of+a+spaser-based+nanolaser.">Demonstration of a spaser-based nanolaser.</a> Nature. 460, 1110-1112 (2009).</li><li>Zhang, X. Y., Zhang, T., Hu, A., Song, Y. J., Duley, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controllable+plasmonic+antennas+with+ultra+narrow+bandwidth+based+on+silver+nano-flags.">Controllable plasmonic antennas with ultra narrow bandwidth based on silver nano-flags.</a> Appl. Phys. Lett. 101, 153118 (2012).</li><li>Tong, L., Zi, F., Guo, X., Lou, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+microfibers+and+nanofibers:+A+tutorial.">Optical microfibers and nanofibers: A tutorial.</a> Opt. Comm. 285, 4641-4647 (2012).</li><li>Morrissey, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectroscopy,+manipulation+and+trapping+of+neutral+atoms,+molecules,+and+other+particles+using+optical+nanofibers:+A+review.">Spectroscopy, manipulation and trapping of neutral atoms, molecules, and other particles using optical nanofibers: A review.</a> Sensors. 13, 10449-10481 (2013).</li><li>Kien, F. L., Dutta Gupta, S., Balykin, V. I., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+emission+of+a+cesium+atom+near+a+nanofiber:+Efficient+coupling+of+light+to+guided+modes.">Spontaneous emission of a cesium atom near a nanofiber: Efficient coupling of light to guided modes.</a> Phys. Rev. A. 72, 032509 (2005).</li><li>Nayak, K. P., Melentiev, P. N., Morinaga, M., Kien, F. L., Balykin, V. I., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+nanofiber+as+an+efficient+tool+for+manipulating+and+probing+atomic+fluorescence.">Optical nanofiber as an efficient tool for manipulating and probing atomic fluorescence.</a> Opt. Express. 15, 5431-5438 (2007).</li><li>Nayak, K. P., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+atoms+on+an+optical+nanofiber.">Single atoms on an optical nanofiber.</a> New J. Phys. 10, 053003 (2008).</li><li>Nayak, K. P., Kien, F. L., Morinaga, M., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibunching+and+bunching+of+photons+in+resonance+fluorescence+from+a+few+atoms+into+guided+modes+of+an+optical+nanofiber.">Antibunching and bunching of photons in resonance fluorescence from a few atoms into guided modes of an optical nanofiber.</a> Phys. Rev. A. 79, 021801 (2009).</li><li>Yalla, R., Nayak, K. P., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+photon+measurements+from+single+quantum+dots+on+an+optical+nanofiber.">Fluorescence photon measurements from single quantum dots on an optical nanofiber.</a> Opt. Express. 20, 2932-2941 (2012).</li><li>Yalla, R., Kien, F. L., Morinaga, M., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Channeling+of+Fluorescence+Photons+from+Single+Quantum+Dots+into+Guided+Modes+of+Optical+Nanofiber.">Efficient Channeling of Fluorescence Photons from Single Quantum Dots into Guided Modes of Optical Nanofiber.</a> Phys. Rev. Lett. 109, 063602 (2012).</li><li>Kien, F. L., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cavity-enhanced+channeling+of+emission+from+an+atom+into+a+nanofiber.">Cavity-enhanced channeling of emission from an atom into a nanofiber.</a> Phys. Rev. A. 80, 053826 (2009).</li><li>Kato, S., Aoki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strong+coupling+between+a+trapped+single+atom+and+an+all-fiber+cavity.">Strong coupling between a trapped single atom and an all-fiber cavity.</a> Phys. Rev. Lett. 115, 093603 (2015).</li><li>Hoffman, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+transmission+optical+nanofibers.">Ultrahigh transmission optical nanofibers.</a> AIP Advances. 4, 067124 (2014).</li><li>Nayak, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cavity+formation+on+an+optical+nanofiber+using+focused+ion+beam+milling+technique.">Cavity formation on an optical nanofiber using focused ion beam milling technique.</a> Opt. Express. 19, 14040-14050 (2011).</li><li>Kien, F. L., Nayak, K. P., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanofibers+with+Bragg+gratings+from+equidistant+holes.">Nanofibers with Bragg gratings from equidistant holes.</a> J. Modern Opt. 59, 274-286 (2012).</li><li>Nayak, K. P., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photonic+crystal+formation+on+optical+nanofibers+using+femtosecond+laser+ablation+technique.">Photonic crystal formation on optical nanofibers using femtosecond laser ablation technique.</a> Opt. Express. 21, 2480-2490 (2013).</li><li>Nayak, K. P., Zhang, P., Hakuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+nanofiber-based+photonic+crystal+cavity.">Optical nanofiber-based photonic crystal cavity.</a> Opt. Lett. 39, 232-235 (2014).</li><li>Becker, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fiber+Bragg+grating+inscription+combining+DUV+sub-picosecond+laser+pulses+and+two-beam+interferometry.">Fiber Bragg grating inscription combining DUV sub-picosecond laser pulses and two-beam interferometry.</a> Opt. Express. 16, 19169-19178 (2008).</li></ol>

The authors have nothing to disclose.

纳米纤维的透镜效应起着在制造技术中起重要作用，从而产生纳米纤维的阴影表面上的纳米环形山（ 图2中示出）。纳米纤维的透镜效应也使制造工艺健壮在横向方向（Y轴）的任何机械不稳定性。而且，由于单发照射，沿着其它轴的不稳定性不作为照射时间仅为120飞秒（ 即脉冲宽度）影响的制造。其结果是，具有良好定义的周期性的周期性纳米结构被制造在几千周期的，不采?...

在纳米光子器件的光强约束光学科学开辟了新的领域。现代纳米加工技术已经在激射1，传感2和光学开关应用3启用1-D和2-D光子晶体（PHC）空腔为新的前景的制造。此外，在这些光子晶体腔强大的光与物质相互作用的量子信息科学4开辟了新的途径。除了光子晶体腔，等离子nanocavities也表现出广阔的发展前景5，6，7。然而，接口这种空腔基于光纤的通信网络仍然是一个挑战。 近年来，锥形单模光纤用亚波长直径，称为光学纳米纤维，已成为一个有前途的纳米光子器件。由于强纳米纤维引导字段，并与周围介质相互作用的能力的横向限制，纳米纤维被广泛地适于并研究了各种纳米光子应用8。除此之外，它也坚决查处和光量子调控实施和物质9。从量子发射器等，单个/少量激光冷却原子和单一量子点，进入纳米纤维引导模式发射的有效耦合已经研究并证实10，11，12，13，14，15。上的纳米纤维的光-物质相互作用可通过在纳米纤维16，17实施光子晶体腔结构可显著改善。 对于s的关键优势UCH的系统是纤维在线技术，可容易地集成到通信网络。通过锥形纳米纤维的99.95％的透光率已经证实18。然而，纳米纤维传输是非常容易受到灰尘和污染。因此，光子晶体结构上采用传统的纳米加工技术，纳米纤维制造是不是卓有成效。虽然使用聚焦离子束（FIB）铣削的纳米纤维空腔制造已证实19，20，该光学质量和再现性不高。 在这个视频协议，我们提出了一个最近展示了21，22的技术来制造使用飞秒激光烧蚀纳米光子晶体腔。捏造是通过在纳米纤维和辐照的创建飞秒激光器的双光束干涉图案进行iating单一飞秒激光脉冲。纳米纤维的透镜效应起着这种技术的可行性的重要作用，纳米纤维的阴影表面上创建烧蚀弹坑。对于一个典型的样品，用了一段350纳米和直径为50逐渐变化的周期性纳米弹坑 - 250纳米以上1mm的长度上制造纳米纤维具有约450直径 - 550纳米。上的纳米纤维这样的周期性纳米火山口，作为一维光子晶体。我们还提出，以控制纳米阵列火山口的轮廓制作的纳米纤维变迹和缺陷引起的光子晶体腔的方法。 这种纳米加工的一个关键方面是所有光学加工，以使高光学质量可以维持。此外，在制造由只是一个单一的飞秒激光脉冲的照射完成，使得技术不受机械不稳定性和其它制造缺陷。这也使得内部生产光子晶体纳米纤维空腔使污染的可能性最小化。该协议旨在帮助他人实施并适应这种新型纳米加工技术。 图1a示出了制造安装的示意图。的制造安装和对准过程的细节将在21 所讨论的，22。飞秒激光具有400nm的中心波长和120飞秒脉冲宽度为入射在相位掩模。相位掩模分割飞秒激光束在0和±1的订单。光束块用于阻断0阶光束。折叠反射镜对称地重组的±1订单在纳米纤维的位置，以创建一个干涉图案。相位掩模的间距为700纳米，因此干涉图案具有350nm的间距（ΛG）。圆柱透镜聚焦沿纳米纤维的飞秒激光束。穿过光束尺寸（Y轴）和沿（Z轴）的纳米纤维为60微米和5.6毫米。锥形光纤被安装在用于拉伸纤维装有压电致动器（PZT）的保持器。与玻璃板的顶盖用于保护从灰尘纳米纤维。与锥形纤维支架固定配备了翻译（XYZ）和旋转（θ）级的制造板凳上。的θ-阶段允许在YZ面内的纳米纤维样品的旋转。 X台还可以控制沿XY-和XZ平面的倾斜角。 CCD照相机放置在距离纳米纤维20厘米的距离，并在45°在XY平面内以监测纳米纤维位置的角度。所有的实验都配备有HEPA（高效率微粒式止）过滤器，以实现无尘条件干净亭内部进行。无尘条件是维持纳米纤维的传输是必不可少的。 图1B显示了光学测量的原理图。光纤耦合光源到锥形光纤和测量使用高分辨率频谱分析仪的透射和反射的光的光谱 - :在制造过程中，光学性质简要通过启动一个宽带（900纳米700波长范围）监测。可调谐连续激光源来妥善解决腔模式和测量绝对腔传输。 我们提出的协议制造和表征。该协议部分在三个小节，纳米纤维的制备，飞秒激光制备与表征所制作的样品分。

<table border="0" cellpadding="0" cellspacing="0" width="828">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:309px;">Femtosecond Laser</td>
			<td style="width:219px;">Coherent Inc.</td>
			<td style="width:236px;">Libra HE</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Phase Mask</td>
			<td>Ibsen Photonics</td>
			<td>Custom Made</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Optial Nanofiber Manufacturing Equipment&#160;&#160;</td>
			<td>Ishihara Sangyo</td>
			<td>ONME</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ADC Card</td>
			<td>PicoTech</td>
			<td>ADC-24</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Single mode fiber</td>
			<td>Fujikura</td>
			<td>FutureGuide-SM</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Broadband source</td>
			<td>NKT Photonics</td>
			<td>SuperK EXTREME</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CW Tunable Laser</td>
			<td>Coherent Inc.</td>
			<td>MBR-110</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Spectrum analyser (Transmission spectrum)</td>
			<td>Thermo Fisher Scientific</td>
			<td>Nicolet 8700</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Spectrum analyser (Reflection spectrum)</td>
			<td>Ocean Optics</td>
			<td>QE65000</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CCD Camera</td>
			<td>Thorlabs</td>
			<td>DCC1545M</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Power Meter</td>
			<td>Thorlabs</td>
			<td>D3MM</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Pt-Coater</td>
			<td>Vacuum Device Inc.</td>
			<td>MSP-1S</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Scanning Electron Microscope</td>
			<td>Keyence</td>
			<td>VE-9800</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">UV Curable Epoxy</td>
			<td>NTT-AT</td>
			<td>AT8105</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Photodiode</td>
			<td>ThorLabs</td>
			<td>PDA 36A-EC</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Clean room wipe</td>
			<td>TExWipe</td>
			<td>TX-404</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fiber coating stripper</td>
			<td>NTT-AT</td>
			<td>Fiber nippers 250 &#956;m&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cover glass</td>
			<td>Matsunami Glass IND,LTD</td>
			<td>NEO micro cover glass 0.12-0.17 mm&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">PZT</td>
			<td>NOLIAC</td>
			<td>NAC 2011-H20</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cylindrical lens stage</td>
			<td>NewPort</td>
			<td>M-481-A&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Y,Z stages</td>
			<td>Chuo Precision Industrial Co., LTD.</td>
			<td>LD-149-C7</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Rotation stage</td>
			<td>SIGMA KOKI</td>
			<td>KSPB-1026MH</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Z-stage(1), Z-stage(2)</td>
			<td>NewPort</td>
			<td>M-460P&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fiber coating stripper</td>
			<td>NTT-AT</td>
			<td>Fiber nippers 250 &#956;m&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

fabrication of 1-d photonic crystal cavity on a nanofiber using femtosecond laser-induced ablation

我们提出的亚波长直径锥形光纤，光学纳米纤维，采用飞秒激光诱导消融制造1-D光子晶体（PHC）腔的协议。我们发现，成千上万的周期性纳米陨石坑是由只有一个单一的飞秒激光脉冲照射在光学纳米纤维制造。对于一个典型的样品，用了一段350纳米和直径为50逐渐变化的周期性纳米弹坑 - 250纳米以上1mm的长度上制造纳米纤维具有约450直径 - 550纳米。这样的纳米加工的一个关键方面是，纳米纤维本身作为一个柱面透镜和集中在它的影子表面飞秒激光束。此外，单杆制造使其不受机械不稳定性和其他制造缺陷。上的纳米纤维这样的周期性纳米火山口，作为一维光子晶体和使强和宽带反射，同时保持了阻带的高传输。我们还提出，以控制纳米阵列火山口的轮廓制作的纳米纤维变迹和缺陷引起的光子晶体腔的方法。该字段的强约束，横向和纵向，在基于纳米纤维，光子晶体空穴和高效整合的光纤网络，可以打开纳米光子应用和量子信息科学的新的可能性。

图2示出了所制造的纳米纤维样品的典型部分的SEM图像。它表明上形成的纳米纤维的阴影侧周期性纳米环形山是，具有相应孔的干涉图案350nm的周期性。插图示出了样品的放大图。纳米弹坑的形状几乎是圆形的，并且一个典型的纳米火山口的直径大约为210纳米。 图3a示出了变迹光子晶体腔的制造的效果...

Watch this Scientific Journal Video about Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation at JoVE.com

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

我们提出了关于使用飞秒激光诱导亚波长消融直径石英光纤（光学纳米）制造1-D光子晶体腔的协议。

1-D光子晶体空穴对纳米纤维使用飞秒激光诱导消融制造

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using ...

fabrication-1-d-photonic-crystal-cavity-on-nanofiber-using

Research

JoVE Journal

Engineering

9.7K 次观看.  University of Electro-Communications. 我们提出了关于使用飞秒激光诱导亚波长消融直径石英光纤（光学纳米）制造1-D光子晶体腔的协议。 

视频: Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities

Slow light has been one of the hot topics in the photonics community in the past decade, generating great interest both from a fundamental point of view and for its considerable potential for practical applications. Slow light photonic crystal waveguides, in particular, have played a major part and have been successfully employed for delaying optical signals1-4 and the enhancement of both linear5-7 and nonlinear devices.8-11
Photonic crystal cavities achieve similar effects to that of slow light waveguides, but over a reduced band-width. These cavities offer high Q-factor/volume ratio, for the realization of optically12 and electrically13 pumped ultra-low threshold lasers and the enhancement of nonlinear effects.14-16 Furthermore, passive filters17 and modulators18-19 have been demonstrated, exhibiting ultra-narrow line-width, high free-spectral range and record values of low energy consumption.
To attain these exciting results, a robust repeatable fabrication protocol must be developed. In this paper we take an in-depth look at our fabrication protocol which employs electron-beam lithography for the definition of photonic crystal patterns and uses wet and dry etching techniques. Our optimised fabrication recipe results in photonic crystals that do not suffer from vertical asymmetry and exhibit very good edge-wall roughness. We discuss the results of varying the etching parameters and the detrimental effects that they can have on a device, leading to a diagnostic route that can be taken to identify and eliminate similar issues.
The key to evaluating slow light waveguides is the passive characterization of transmission and group index spectra. Various methods have been reported, most notably resolving the Fabry-Perot fringes of the transmission spectrum20-21 and interferometric techniques.22-25 Here, we describe a direct, broadband measurement technique combining spectral interferometry with Fourier transform analysis.26 Our method stands out for its simplicity and power, as we can characterise a bare photonic crystal with access waveguides, without need for on-chip interference components, and the setup only consists of a Mach-Zehnder interferometer, with no need for moving parts and delay scans.
When characterising photonic crystal cavities, techniques involving internal sources21 or external waveguides directly coupled to the cavity27 impact on the performance of the cavity itself, thereby distorting the measurement. Here, we describe a novel and non-intrusive technique that makes use of a cross-polarised probe beam and is known as resonant scattering (RS), where the probe is coupled out-of plane into the cavity through an objective. The technique was first demonstrated by McCutcheon et al.28 and further developed by Galli et al.29

Use of photonic crystal slow light waveguides and cavities has been widely adopted by the photonics community in many differing applications. Therefore fabrication and characterization of these devices are of great interest. This paper outlines our fabrication technique and two optical characterization methods, namely: interferometric (waveguides) and resonant scattering (cavities).

光子晶体慢光波导和腔体的制备与表征

Slow light has been one of the hot topics in the photonics community in the past decade, generating great interest both from a fundamental point of view ...

科研

工程学

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system.&#160; Spectrally-resolved and time-resolved experimental configurations are described, including the use of zero-background autocorrelation techniques for pulse optimization.&#160; The etching process used to prepare GaMnAs samples for four-wave mixing experiments is also highlighted.&#160; The high temporal resolution of this technique, afforded by the use of short (20 fsec) optical pulses, permits the rapid spin-flip scattering process in this system to be studied directly in the time domain, providing new insight into the strong exchange coupling responsible for carrier-mediated ferromagnetism.&#160; We also show that spectral resolution of the four-wave mixing signal allows one to extract clear signatures of (s,p)-d hybridization in this system, unlike linear spectroscopy techniques.&#160;&#160; This increased sensitivity is due to the nonlinearity of the technique, which suppresses defect-related contributions to the optical response. This method may be used to measure the time scale for coherence decay (tied to the fastest scattering processes) in a wide variety of semiconductor systems of interest for next generation electronics and optoelectronics.

The technique of femtosecond four-wave mixing is described, including spectrally-resolved and time-resolved configurations. We illustrate the utility of this technique for the investigation of crucial physical properties in the III-V diluted magnetic semiconductors, afforded by its nonlinearity and high temporal resolution.

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, ...

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). In this article we will describe the methods for constructing and characterizing macroscopic disordered photonic structures using microwaves. The microwave regime offers the most convenient experimental sample size to build and test PBG media. Easily manipulated dielectric lattice components extend flexibility in building various 2D structures on top of pre-printed plastic templates. Once built, the structures could be quickly modified with point and line defects to make freeform waveguides and filters. Testing is done using a widely available Vector Network Analyzer and pairs of microwave horn antennas. Due to the scale invariance property of electromagnetic fields, the results we obtained in the microwave region can be directly applied to infrared and optical regions. Our approach is simple but delivers exciting new insight into the nature of light and disordered matter interaction.

Our representative results include the first experimental demonstration of the existence of a complete and isotropic PBG in a two-dimensional (2D) hyperuniform disordered dielectric structure. Additionally we demonstrate experimentally the ability of this novel photonic structure to guide electromagnetic waves (EM) through freeform waveguides of arbitrary shape.

Disordered structures offer new mechanisms for forming photonic bandgaps and unprecedented freedom in functional-defect designs. To circumvent the computational challenges of disordered systems, we construct modular macroscopic samples of the new class of PBG materials and use microwaves to characterize their scale-invariant photonic properties, in an easy and inexpensive manner.

利用微波和电介质固体的宏观样本，研究无序光子带隙材料的光子特性

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). ...

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics industry. In this technique the chip and/or the substrate is bumped and the two are bonded via these conductive bumps. Many bumping techniques have been developed and intensively investigated since the introduction of the FC technology in 19601 such as stencil printing, stud bumping, evaporation and electroless/electroplating2. Despite the progress that these methods have made they all suffer from one or more than one drawbacks that need to be addressed such as cost, complex processing steps, high processing temperatures, manufacturing time and most importantly the lack of flexibility. In this paper, we demonstrate a simple and cost-effective laser-based bump forming technique known as Laser-induced Forward Transfer (LIFT)3. Using the LIFT technique a wide range of bump materials can be printed in a single-step with great flexibility, high speed and accuracy at RT. In addition, LIFT enables the bumping and bonding down to chip-scale, which is critical for fabricating ultra-miniature circuitry.

We demonstrate the use of the Laser-induced Forward Transfer (LIFT) technique for flip-chip assembly of optoelectronic components. This approach provides a simple, cost-effective, low-temperature, fast and flexible solution for fine-pitch bumping and bonding on chip-scale for achieving high-density circuits for optoelectronic applications.

激光诱导转发转移单人死于倒装芯片封装

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics ...

Laser-induced Forward Transfer of Ag Nanopaste

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of these processes such as inkjet3 and laser-induced forward transfer (LIFT)4 have become increasingly popular as interest in printable electronics and maskless patterning has grown. These additive manufacturing processes are inexpensive, environmentally friendly, and well suited for rapid prototyping, when compared to more traditional semiconductor processing techniques. While most direct-write processes are confined to two-dimensional structures and cannot handle materials with high viscosity (particularly inkjet), LIFT can transcend both constraints if performed properly. Congruent transfer of three dimensional pixels (called voxels), also referred to as laser decal transfer (LDT)5-9, has recently been demonstrated with the LIFT technique using highly viscous Ag nanopastes to fabricate freestanding interconnects, complex voxel shapes, and high-aspect-ratio structures. In this paper, we demonstrate a simple yet versatile process for fabricating a variety of micro- and macroscale Ag structures. Structures include simple shapes for patterning electrical contacts, bridging and cantilever structures, high-aspect-ratio structures, and single-shot, large area transfers using a commercial digital micromirror device (DMD) chip.

We demonstrate the use of the Laser-induced forward transfer technique (LIFT) for the printing of high-viscosity Ag paste. This technique offers a simple, low temperature, robust process for non-lithographically printing microscale 2D and 3D structures.

银纳米糊膏的激光诱导正向传输

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of ...

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). Resonant excitation without fluorescence detection &#8211; for example, a differential transmission measurement &#8211; can determine some properties of the emitting system, but does not allow applications or measurements based on the emitted photons. For example, the measurement of photon correlations, observation of the Mollow triplet, and realization of single photon sources all require collection of the fluorescence. Incoherent excitation with fluorescence detection &#8211; for example, above band-gap excitation &#8211; can be used to create single photon sources, but the disturbance of the environment due to the excitation reduces the indistinguishability of the photons. Single photon sources based on QDs will have to be resonantly excited to have high photon indistinguishability, and simultaneous collection of the photons will be necessary to make use of them. We demonstrate a method to resonantly excite a single QD embedded in a planar cavity by coupling the excitation beam into this cavity from the cleaved face of the sample while collecting the fluorescence along the sample&#39;s surface normal direction. By carefully matching the excitation beam to the waveguide mode of the cavity, the excitation light can couple into the cavity and interact with the QD. The scattered photons can couple to the Fabry-Perot mode of the cavity and escape in the surface normal direction. This method allows complete freedom in the detection polarization, but the excitation polarization is restricted by the propagation direction of the excitation beam. The fluorescence from the wetting layer provides a guide to align the collection path with respect to the excitation beam. The orthogonality of the excitation and detection modes enables resonant excitation of a single QD with negligible laser scattering background.

Resonant excitation of a single self-assembled quantum dot can be achieved using an excitation mode orthogonal to the fluorescence collection mode. We demonstrate a method using the waveguide and Fabry-Perot modes of a planar microcavity surrounding the quantum dots. The method allows complete freedom in the detection polarization.

用正交激励和检测方法研究平面腔内铟量子点的共振荧光

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). ...

Preparation of Large-area Vertical 2D Crystal Hetero-structures Through the Sulfurization of Transition Metal Films for Device Fabrication

We have demonstrated that through the sulfurization of transition metal films such as molybdenum (Mo) and tungsten (W), large-area and uniform transition metal dichalcogenides (TMDs) MoS2 and WS2 can be prepared on sapphire substrates. By controlling the metal film thicknesses, good layer number controllability, down to a single layer of TMDs, can be obtained using this growth technique. Based on the results obtained from the Mo film sulfurized under the sulfur deficient condition, there are two mechanisms of (a) planar MoS2 growth and (b) Mo oxide segregation observed during the sulfurization procedure. When the background sulfur is sufficient, planar TMD growth is the dominant growth mechanism, which will result in a uniform MoS2 film after the sulfurization procedure. If the background sulfur is deficient, Mo oxide segregation will be the dominant growth mechanism at the initial stage of the sulfurization procedure. In this case, the sample with Mo oxide clusters covered with few-layer MoS2 will be obtained. After sequential Mo deposition/sulfurization and W deposition/sulfurization procedures, vertical WS2/MoS2 hetero-structures are established using this growth technique. Raman peaks corresponding to WS2 and MoS2, respectively, and the identical layer number of the hetero-structure with the summation of individual 2D materials have confirmed the successful establishment of the vertical 2D crystal hetero-structure. After transferring the WS2/MoS2 film onto a SiO2/Si substrate with pre-patterned source/drain electrodes, a bottom-gate transistor is fabricated. Compared with the transistor with only MoS2 channels, the higher drain currents of the device with the WS2/MoS2 hetero-structure have exhibited that with the introduction of 2D crystal hetero-structures, superior device performance can be obtained. The results have revealed the potential of this growth technique for the practical application of 2D crystals.

Through the sulfurization of pre-deposited transition metals, large-area and vertical 2D crystal hetero-structures can be fabricated. The film transferring and device fabrication procedures are also demonstrated in this report.

硫化过渡金属膜制备大面积垂直2D 晶体杂化结构

We have demonstrated that through the sulfurization of transition metal films such as molybdenum (Mo) and tungsten (W), large-area and uniform transition ...

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

基于范德华 Heteroepitaxy 的柔性铁电元件制备及测量方法

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

基于侧向 NIPIN Phototransistors 的柔性图像传感器的研制

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared on transparent membranes which are very fragile and difficult to manipulate. We present processes for the fabrication of samples with magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for Lorentz transmission electron microscopy and magnetic transmission x-ray microscopy studies. The samples are prepared on silicon nitride membranes and the fabrication consists of a spin coating, UV and electron-beam lithography, the chemical development of the resist, and the evaporation of the magnetic material followed by a lift-off process forming the final magnetic structures. The samples for the Lorentz transmission electron microscopy consist of magnetic nanodiscs prepared in a single lithography step. The samples for the magnetic x-ray transmission microscopy are used for time-resolved magnetization dynamic experiments, and magnetic nanodiscs are placed on a waveguide which is used for the generation of repeatable magnetic field pulses by passing an electric current through the waveguide. The waveguide is created in an extra lithography step.

A protocol for the fabrication of magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for transmission electron microscopy (TEM) and magnetic transmission x-ray microscopy (MTXM) studies is presented.

用透射显微技术制备氮化硅薄膜磁性纳米结构的研究

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...