• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Multi-band asymmetric transmissions based on bi-layer windmill-shaped metamaterial*

    2021-11-23 07:28:18YingHuaWang王英華JieLi李杰ZhengGaoDong董正高YanLi李妍andXuZhang張旭
    Chinese Physics B 2021年11期
    關(guān)鍵詞:李妍英華李杰

    Ying-Hua Wang(王英華) Jie Li(李杰) Zheng-Gao Dong(董正高) Yan Li(李妍) and Xu Zhang(張旭)

    1School of Physics and Physical Engineering,Shandong Provincial Key Laboratory of Laser Polarization and Information Technology,Qufu Normal University,Qufu 273165,China

    2Gr¨unberg Research Centre,Nanjing University of Posts and Telecommunications,Nanjing 210023,China

    3School of Physics,Southeast University,Nanjing 211189,China

    Keywords: metamaterial,multi-band,asymmetric transmission,polarization conversion

    1. Introduction

    Metamaterials and metasurfaces have become an important research field because they present powerful capacities for manipulating the fundamental properties of the propagating electromagnetic waves due to the flexible design of subwavelength geometric shapes and sizes.[1,2]In addition, acoustic metamaterials are also proposed to investigate the transmission spectra and sound insulation performance.[3,4]Since the proposal of the concept of metamaterials,several novel structures have been reported, ranging from microwave to optical regimes,such as I-shaped metamaterials,split-ring resonators,L-shaped metallic antennas, and S-shaped holes.[5-9]Since then, many studies have paid attention to focusing beams,[10]creating orbital angular momentum,[11]and manipulating the polarization states,phases,and modes of TE/TM waves.[12,13]In 2007, Zhouet al.proposed an I-shaped metamaterial to manipulate the polarization of electromagnetic waves and achieved complete conversion between two perpendicular linear polarizations.[9]In 2020, broadband linear-to-circular polarization conversion was realized among reflected waves.[14]In addition, metamaterials have been used to realize perfect absorption,circular dichroism,optical activity,and the asymmetric transmission(AT)effect.[15-20]

    In recent decades, the AT effect has garnered increasing attention. To realize outstanding and tunable AT effects in linearly and circularly polarized plane waves, several studies have been conducted, such as changing the shapes of symmetry-broken chiral metastructures,[21,22]increasing the layers of the proposed nanobars,[23,24]and tilting the rectangular nanoholes.[25]With regard to circularly polarized plane waves, high-efficiency broadband and dualband AT effects have been studied and realized from microwave to optical regimes,[20,26-28]and tunable AT effects have also been realized by integrating the graphene layers with metamaterials.[29-31]With regard to linearly polarized plane waves, several studies have focused on enhancing the efficiency and broadening the band of the AT effect. In these studies,the AT effect in the microwave regime achieved better results than those in the optical regime. For instance, dualband, broadband, and multi-band AT effects have been realized in the microwave regime with high efficiency.[21,32,33]In comparison with the microwave regime, most studies on the near-infrared regime have realized the broadband or dual-band AT effect with low efficiencies.[33-35]For example,Zhang realized both circularly and linearly polarized AT effects using one-layer metamaterials, but the AT values were about 0.1.[25,29]To increase the AT values, more works paid attention to bi-layer metamaterials,then I-L-shaped,S-shaped,split ring-shaped Ω-shaped metamaterial, and many other metamaterials were proposed, and the AT values increased to 0.8.[35-40]For further increases in AT effects,multilayer metamaterial has also been proposed and the AT values have been increased to 0.9. But here, the multilayer metamaterials increase the complexity and difficulty of the fabrication process,so it is necessary to enhance and broaden the AT effects using bi-layer metamaterials.[24,41,42]In previous works, the dualband AT effect has also been realized by bi-layer metamaterial with a maximum of about 0.75,[8,32,43,44]but a few studies have reported the multi-band AT effect and its tunable properties. According to the multi-band absorption, multi-band polarization conversion, and multi-band circular dichroism and other multi-band electromagnetic effects, we know that it is useful to study the multi-band AT effect on the near-infrared regime.[45-47]

    In this study, we propose a bi-layer windmill-shaped metamaterial and numerically investigate the multi-band AT effect and its tunable properties using the finite-difference time-domain method. In comparison with the split-ring resonator, the windmill-shaped resonators can motivate and enhance more resonant modes. Consequently, the simulated results demonstrate that the AT values are greater than 0.5 at 195,260, and 309 THz. Moreover, the high-efficiency AT effects can be flexibly tuned by modulating the geometric parameters of the proposed metamaterial.For instance,the bandwidth can be tuned by changing the sizes,whereas the polarization state of the transmitted plane wave can be tuned by changing the gap between the first and second layers. The additional operating frequency bands and tunable properties provide more application possibilities for the AT effect in the future.

    2. Design and structure

    Firstly,we discuss the principles of the bi-layer windmillshaped metamaterial design. When a linearly polarized plane wave is propagating in the +zdirection, the illuminated and transmitted electric field can be given by[48,49]

    According to Eqs.(8)-(10)we can getTxx=Tyy. In addition,the windmill arms play an important role in inducing and enhancing multi-band resonances.[50]As a result, the bi-layer windmill-shaped resonator can result in a multi-band AT effect for only linearly polarized plane waves.[48-50]

    Fig.1. (a)A unit cell of bi-layer windmill-shaped resonators with blue and red arrows indicating the forward and backward incidences,respectively. (b)and(c)The first and second layers of the unit cell.

    Based on the design principles the bi-layer windmillshaped resonator is proposed and shown in Fig.1. Figure 1(a)presents the perspective view of a unit cell of this resonator,where the two windmill-shaped metallic layers are separated(g= 70 nm) by a silicon oxide dielectric spacer layer with a permittivity ofεsio2=2.1. The windmill-shaped metallic layers are made of silver with a Drude-type dispersion, for which the plasma and collision frequencies areωp=1.367×107rad/s andγ=7.73×1013rad/s,respectively,and the highfrequency bulk permittivityε∞=6.0. The blue and red arrows indicate that thex- andy-polarized plane waves propagate along the forward (+z) and backward (?z) directions,respectively. Figures 1(b)and 1(c)respectively show the first and second layers of the windmill-shaped resonators with the periodp=500 nm. The other geometric parameters of the windmill-shaped resonator are set ast=40 nm,w=80 nm,d=100 nm,ands=50 nm.

    3. Results and discussion

    Fig. 2. Simulated transmission coefficients of windmill-shaped resonators,when x-and y-polarized plane waves incident along the(a)forward and(b)backward directions, respectively. I, II, and III show three resonances at 195 THz,260 THz,and 309 THz,respectively.

    By studying the geometric parameters of the windmillshaped metamaterial,we found that the multi-band AT can be flexibly tuned. First, Fig. 4(a) shows that the sizescan easily tune resonant modes II and III,i.e.,whensincreases from 0 nm to 140 nm, the AT parameters decrease from 0.72 to 0.Meanwhile, the AT parameters increase from 0 to 0.72, and the operation bands of the AT are also broadened in resonant mode III.In addition, Fig.4(b)shows that the gapgbetween the first and second layers can tune resonant modes I and III,i.e., whengincreases from 40 nm to 250 nm, the AT parameters decrease. A new resonant mode IV is induced whengis increased. Resonant mode IV results in opposite polarization conversions and the AT phenomenon at 343 THz, where thex-polarized incident plane wave can be transformed into ay-polarized output plane wave when it propagates in the backward direction and the maximum AT parameter is?0.6 wheng=190 nm.In other words,wheng=190 nm,thex-polarized incident plane wave can pass through this bi-layer windmillshaped metamaterial along the backward(?z)direction,which is opposite to resonant modes I,II,and III.

    Fig.3. (a)and(b)The calculated total transmittances for x-and y-polarized excitations propagating along the forward and backward directions. (c)The AT parameters for the designed windmill-shaped resonators. Solid and hollow triangular lines correspond to the AT of the x- and y-polarized plane waves,respectively.

    To understand the physical mechanism of the multi-band AT phenomenon, we studied the surface current distributions of this bi-layer windmill-shaped metamaterial in resonant modes I, II, III, and IV. The horizontal red arrows in Figs.5(a)-5(c)represent thex-polarized incident plane wave.Figure 5(a) shows that resonant mode I at 195 THz is induced by a design that is parallel to the split arms. Figure 5(b)shows that resonant mode II at 260 THz is induced by the center split rings, identical to the traditional split-ring resonators(SRRs)without windmill-shaped arms.[21,43,49,52]The surface current passes through the spilledsand results in a magnetic dipole resonance; thus, resonant mode II can be easily tuned by changing the size ofs. Figure 5(c) shows that resonant mode III at 309 THz is also induced by the design of the windmill-shaped arms, in contrast to resonant mode I, where the surface focuses on the two corners of the L-shaped arms,which are included and parallel to the split arms; therefore,the parameterscan tune resonant mode III. In other words,resonant modes I,II,and III are induced by anx-polarized incident plane wave propagating in the forward direction,resulting in thex-polarized plane wave passing through the bi-layer windmill-shaped metamaterial along the forward (+z) direction and transformation to they-polarized output plane wave.Figure 5(d) shows that resonant mode IV at approximately 343 THz is induced when they-polarized incident plane wave propagates in the forward direction, and the surface current distributions are localized on the L-shaped arms, which are perpendicular to the spilled arms. In addition,resonant mode IV can only be activated when the gapgincreases and thexpolarized incident plane wave can only pass through the metamaterial along the backward(?z)direction,which results in a negative AT parameter in resonant mode IV in Fig.4(b).

    Fig.4. The tunable AT effect by changing the(a)spilled width s and(b)gap g between the first and second layers.

    Fig.5.Current distributions of the multi-band resonant modes at polarization conversion peaks for forwarding propagation. (a)-(c)Simulated current distributions at 195,260,and 309 THz for x-polarized incidence. (d)Simulated current distributions at 343 THz for y-polarized incidence.

    Finally, we also consider the effect of the geometric parameterspanddon the AT parameter. In Fig. 6(a), when the periodpincreases from 500 nm to 800 nm, the couplings among neighboring periods decrease,and thus the resonances in modes I, II, and III are weakened, which results in a decrease in the AT parameters. In Fig. 6(b), we first setp=500 nm,but setd=0 nm and 100 nm. Whend=0 nm,the traditional SRRs without windmill-shaped arms are substituted for our bi-layer windmill-shaped metamaterial,and consequently,the AT parameter only appears at 260 THz(resonant mode II). Further, whendis increased to 200 nm, the period also increases and,consequently,the AT parameter decreases.

    Fig. 6. Calculated AT parameters of the bi-layered windmill-shaped splitring resonators for different(a)periods p and(b)windmill arm distances d.

    4. Conclusion

    In this study, we proposed a bi-layer windmill-shaped metamaterial that is different from traditional SRRs,as it can induce more resonant modes and result in multi-band AT in linearly polarized plane waves.The AT parameters reach 0.58,0.74,and 0.62 at 195,260,and 309 THz,respectively.Furthermore,the multi-band AT can be tuned freely by changing the geometric parameterssandg. Wheng=190 nm, a reversed AT was realized at 343 THz with the AT parameter reaching?0.6. To further understand the physical mechanism,the surface current distributions of this bi-layer windmill-shaped metamaterial are presented for the underlying resonant modes I,II,III,and IV,respectively. It is believed that the multi-band AT effects will be applied as polarization rotators and switches in the field of optical nano-devices.

    猜你喜歡
    李妍英華李杰
    Influence of particle size on the breaking of aluminum particle shells
    Empirical Likelihood for Partially Linear Models Under Associated Errors
    人民海軍首次海戰(zhàn)
    源流(2021年11期)2021-03-25 10:32:07
    小胖熊半夜歷險(xiǎn)記
    Zero-Sequence Current Suppression Strategy for Open-End Winding Permanent Magnet Synchronous Motor Based on Model Predictive Control
    小xiǎo雪xuě人rén 多duō 多duo
    論一顆蛀牙的長成
    大眾健康(2019年9期)2019-10-11 04:06:12
    M id-infrared supercontinuum generation and itsapp lication on all-opticalquantization with different inputpulses*
    QUANTILE ESTIMATION WITH AUXILIARY INFORMATION UNDER POSITIVELY ASSOCIATED SAMPLES?
    What’s the Future of Paper Books(節(jié)選)
    欧美一级a爱片免费观看看| 久久6这里有精品| 美女大奶头视频| 国产精品久久久久久久电影| 亚洲丝袜综合中文字幕| 成年av动漫网址| 久久精品国产亚洲网站| 欧美成人a在线观看| 视频中文字幕在线观看| 精品久久久久久电影网| 精品人妻偷拍中文字幕| 黄色一级大片看看| 国产 一区 欧美 日韩| 免费在线观看成人毛片| 18禁在线无遮挡免费观看视频| 夫妻午夜视频| 男女下面进入的视频免费午夜| 午夜福利在线在线| 免费观看在线日韩| 免费av不卡在线播放| 天天一区二区日本电影三级| 赤兔流量卡办理| 亚洲久久久久久中文字幕| 一本一本综合久久| 日韩av在线大香蕉| 色综合站精品国产| 久久久成人免费电影| 国产乱人视频| 欧美日韩一区二区视频在线观看视频在线 | 免费看不卡的av| 99久国产av精品| 97精品久久久久久久久久精品| 欧美成人一区二区免费高清观看| 成人特级av手机在线观看| 亚洲综合色惰| 91久久精品电影网| 网址你懂的国产日韩在线| 欧美人与善性xxx| kizo精华| 亚洲精华国产精华液的使用体验| 青春草视频在线免费观看| 熟妇人妻不卡中文字幕| 如何舔出高潮| 亚洲精品成人av观看孕妇| 亚洲欧美清纯卡通| 欧美成人一区二区免费高清观看| 欧美日韩视频高清一区二区三区二| 丰满乱子伦码专区| 亚洲18禁久久av| 久久精品夜夜夜夜夜久久蜜豆| 免费高清在线观看视频在线观看| 寂寞人妻少妇视频99o| 黄色一级大片看看| 免费大片黄手机在线观看| 亚洲在久久综合| 尾随美女入室| 国产精品99久久久久久久久| 国产又色又爽无遮挡免| 一级毛片aaaaaa免费看小| 免费少妇av软件| 熟妇人妻不卡中文字幕| 免费在线观看成人毛片| 中文乱码字字幕精品一区二区三区 | 搡老乐熟女国产| 精品久久国产蜜桃| 午夜激情久久久久久久| 国产精品一区二区三区四区久久| 亚洲伊人久久精品综合| 久久这里只有精品中国| av免费观看日本| 日韩精品有码人妻一区| 3wmmmm亚洲av在线观看| 少妇人妻一区二区三区视频| 亚洲av国产av综合av卡| 亚洲精品aⅴ在线观看| 亚洲第一区二区三区不卡| 熟女电影av网| 精品酒店卫生间| 国产探花极品一区二区| 熟妇人妻久久中文字幕3abv| 看黄色毛片网站| 免费av不卡在线播放| 伦理电影大哥的女人| 国产探花极品一区二区| 日韩成人伦理影院| 天堂av国产一区二区熟女人妻| 秋霞伦理黄片| 久久这里有精品视频免费| 美女被艹到高潮喷水动态| 久久久午夜欧美精品| 亚洲欧美一区二区三区黑人 | 欧美日韩在线观看h| 免费观看av网站的网址| 91久久精品电影网| 男人舔奶头视频| 国产精品国产三级专区第一集| 男女啪啪激烈高潮av片| 高清午夜精品一区二区三区| av.在线天堂| 99视频精品全部免费 在线| 亚洲av二区三区四区| 日韩成人伦理影院| 18+在线观看网站| 亚洲三级黄色毛片| 别揉我奶头 嗯啊视频| 亚洲av在线观看美女高潮| 中文字幕亚洲精品专区| 91精品国产九色| 免费看av在线观看网站| 天堂俺去俺来也www色官网 | 五月天丁香电影| 一本久久精品| 2021少妇久久久久久久久久久| 国产精品女同一区二区软件| 淫秽高清视频在线观看| 日韩强制内射视频| 中国国产av一级| 最近中文字幕高清免费大全6| 最近中文字幕高清免费大全6| 亚洲精品影视一区二区三区av| 久久韩国三级中文字幕| 午夜免费激情av| 水蜜桃什么品种好| 国产人妻一区二区三区在| 亚洲国产色片| 麻豆成人午夜福利视频| 少妇熟女欧美另类| 久久草成人影院| 极品教师在线视频| 人妻系列 视频| 99久国产av精品| 高清毛片免费看| 成人综合一区亚洲| 国产激情偷乱视频一区二区| 美女被艹到高潮喷水动态| 欧美高清成人免费视频www| 十八禁网站网址无遮挡 | 久久久精品免费免费高清| 国产伦精品一区二区三区四那| 波多野结衣巨乳人妻| 国产伦一二天堂av在线观看| 一个人看视频在线观看www免费| 国内精品一区二区在线观看| h日本视频在线播放| 日本熟妇午夜| 老司机影院毛片| 中文天堂在线官网| 日日啪夜夜撸| 国产 一区精品| 亚洲综合色惰| 精品午夜福利在线看| 国产亚洲最大av| 成人特级av手机在线观看| 亚洲精品国产成人久久av| 国产黄色小视频在线观看| 国产免费视频播放在线视频 | 秋霞伦理黄片| 日韩在线高清观看一区二区三区| 中国美白少妇内射xxxbb| 天天一区二区日本电影三级| 三级经典国产精品| 22中文网久久字幕| 国产午夜精品久久久久久一区二区三区| 国产一区二区在线观看日韩| 草草在线视频免费看| 免费av毛片视频| 黑人高潮一二区| 一级毛片电影观看| 91精品伊人久久大香线蕉| 婷婷色综合www| 少妇熟女欧美另类| 国产乱人偷精品视频| 亚洲精品一区蜜桃| 少妇的逼水好多| 欧美+日韩+精品| 黄色日韩在线| 亚洲av国产av综合av卡| 自拍偷自拍亚洲精品老妇| 亚洲国产av新网站| 亚洲一级一片aⅴ在线观看| 日韩av免费高清视频| 激情五月婷婷亚洲| 日韩成人av中文字幕在线观看| 综合色丁香网| 色播亚洲综合网| 在线观看人妻少妇| 老女人水多毛片| 天堂av国产一区二区熟女人妻| 国产探花极品一区二区| 在线a可以看的网站| 国产午夜福利久久久久久| 久久久午夜欧美精品| 精品久久久久久久久亚洲| 一本—道久久a久久精品蜜桃钙片 精品乱码久久久久久99久播 | 久久久久久久亚洲中文字幕| 最近最新中文字幕大全电影3| 免费观看精品视频网站| 80岁老熟妇乱子伦牲交| 人妻一区二区av| 国产黄片美女视频| 久久亚洲国产成人精品v| 校园人妻丝袜中文字幕| 九草在线视频观看| 99久久精品一区二区三区| 看非洲黑人一级黄片| 久热久热在线精品观看| 三级国产精品片| 男人狂女人下面高潮的视频| 久热久热在线精品观看| 日韩欧美国产在线观看| 午夜免费男女啪啪视频观看| 又爽又黄a免费视频| 亚洲精品一区蜜桃| 国产免费又黄又爽又色| 国产伦一二天堂av在线观看| 精品国产露脸久久av麻豆 | 婷婷色麻豆天堂久久| 七月丁香在线播放| 国产精品日韩av在线免费观看| 视频中文字幕在线观看| 大香蕉97超碰在线| 啦啦啦啦在线视频资源| 国产在线一区二区三区精| 亚洲av成人精品一区久久| 黄色欧美视频在线观看| 国产精品99久久久久久久久| 久久久久久久久久人人人人人人| 国产精品1区2区在线观看.| 国产一级毛片七仙女欲春2| 欧美日韩在线观看h| 中文精品一卡2卡3卡4更新| 午夜福利视频精品| 在线免费十八禁| 国产乱人偷精品视频| 亚洲最大成人中文| 欧美精品一区二区大全| 亚洲伊人久久精品综合| 97超视频在线观看视频| 亚洲国产欧美人成| 日韩欧美精品免费久久| 国产精品伦人一区二区| 日韩一区二区视频免费看| 三级经典国产精品| av播播在线观看一区| 国产一区亚洲一区在线观看| 日日干狠狠操夜夜爽| 欧美xxxx性猛交bbbb| 狠狠精品人妻久久久久久综合| 国产激情偷乱视频一区二区| 成人亚洲欧美一区二区av| 搡女人真爽免费视频火全软件| 偷拍熟女少妇极品色| 成人av在线播放网站| 99久久人妻综合| www.av在线官网国产| 日产精品乱码卡一卡2卡三| 一边亲一边摸免费视频| 能在线免费看毛片的网站| 欧美日韩亚洲高清精品| 国产亚洲精品av在线| 91久久精品电影网| 亚洲av成人av| 视频中文字幕在线观看| 午夜福利在线观看吧| 国产乱来视频区| 欧美一级a爱片免费观看看| 网址你懂的国产日韩在线| 97人妻精品一区二区三区麻豆| 国产成人福利小说| 亚洲av免费高清在线观看| 天堂影院成人在线观看| 高清视频免费观看一区二区 | 夫妻午夜视频| 老司机影院成人| 内地一区二区视频在线| 国产伦在线观看视频一区| av在线蜜桃| 国产 亚洲一区二区三区 | 激情五月婷婷亚洲| 2021少妇久久久久久久久久久| 国产乱人偷精品视频| 亚洲av二区三区四区| 天天躁夜夜躁狠狠久久av| 欧美精品国产亚洲| 最近手机中文字幕大全| 国产色爽女视频免费观看| 夫妻性生交免费视频一级片| 免费播放大片免费观看视频在线观看| 中文精品一卡2卡3卡4更新| 亚洲精品久久午夜乱码| 成人性生交大片免费视频hd| 国产黄片视频在线免费观看| 男人和女人高潮做爰伦理| 日本三级黄在线观看| 在线播放无遮挡| 亚洲av国产av综合av卡| 久久久国产一区二区| 日韩欧美精品免费久久| 日韩一区二区三区影片| 80岁老熟妇乱子伦牲交| 人体艺术视频欧美日本| 婷婷色综合大香蕉| 激情 狠狠 欧美| 在线 av 中文字幕| 丝瓜视频免费看黄片| 少妇熟女aⅴ在线视频| 国产极品天堂在线| av又黄又爽大尺度在线免费看| 好男人视频免费观看在线| 欧美成人精品欧美一级黄| 精品少妇黑人巨大在线播放| 亚洲精品视频女| 日韩三级伦理在线观看| 两个人视频免费观看高清| 三级国产精品片| 18禁动态无遮挡网站| 免费av观看视频| 国产乱人视频| 日韩av免费高清视频| 一本一本综合久久| 又黄又爽又刺激的免费视频.| 亚洲av二区三区四区| 男人舔女人下体高潮全视频| 啦啦啦中文免费视频观看日本| 久99久视频精品免费| 青春草视频在线免费观看| 身体一侧抽搐| 亚洲一级一片aⅴ在线观看| 日本一二三区视频观看| 成年av动漫网址| 国产高清不卡午夜福利| 亚洲伊人久久精品综合| 欧美成人一区二区免费高清观看| 亚洲av电影不卡..在线观看| 精品久久久久久久人妻蜜臀av| 久久久久久九九精品二区国产| 高清av免费在线| 51国产日韩欧美| 80岁老熟妇乱子伦牲交| 在线观看av片永久免费下载| 日韩av免费高清视频| 99久久精品国产国产毛片| 十八禁国产超污无遮挡网站| 国内精品美女久久久久久| 色吧在线观看| 18禁裸乳无遮挡免费网站照片| 国产亚洲av片在线观看秒播厂 | 日本色播在线视频| 国产黄色小视频在线观看| 又爽又黄无遮挡网站| 亚洲欧美日韩东京热| 男女下面进入的视频免费午夜| 欧美成人一区二区免费高清观看| 极品少妇高潮喷水抽搐| 免费观看av网站的网址| 亚洲精品国产成人久久av| 国产视频内射| 亚洲在久久综合| 久久国产乱子免费精品| 日本免费a在线| 麻豆av噜噜一区二区三区| 国产精品99久久久久久久久| 亚洲乱码一区二区免费版| 99九九线精品视频在线观看视频| 国产精品伦人一区二区| 亚洲,欧美,日韩| 久久精品国产自在天天线| 亚洲国产精品成人综合色| 亚洲av在线观看美女高潮| 亚洲国产高清在线一区二区三| 一边亲一边摸免费视频| 国产乱来视频区| 三级经典国产精品| 欧美精品国产亚洲| 日韩一区二区三区影片| 亚洲国产日韩欧美精品在线观看| 亚洲av中文av极速乱| 在线观看美女被高潮喷水网站| 一级黄片播放器| 国产白丝娇喘喷水9色精品| 亚洲精品乱久久久久久| 亚洲精品第二区| 日本熟妇午夜| 免费电影在线观看免费观看| 春色校园在线视频观看| 80岁老熟妇乱子伦牲交| 国产精品无大码| 18禁在线无遮挡免费观看视频| 观看免费一级毛片| 亚洲激情五月婷婷啪啪| 偷拍熟女少妇极品色| 直男gayav资源| 在线a可以看的网站| 五月玫瑰六月丁香| 老司机影院成人| 国产在线男女| 亚洲成人中文字幕在线播放| 国产成人a∨麻豆精品| 伊人久久国产一区二区| 永久网站在线| 美女xxoo啪啪120秒动态图| 免费黄网站久久成人精品| 永久网站在线| 久久久精品94久久精品| 干丝袜人妻中文字幕| 免费av不卡在线播放| 午夜激情久久久久久久| a级毛色黄片| 看十八女毛片水多多多| 国产成年人精品一区二区| 三级毛片av免费| 亚洲色图av天堂| 亚洲国产欧美人成| 亚洲精品中文字幕在线视频 | 国产亚洲一区二区精品| 精品少妇黑人巨大在线播放| 最近最新中文字幕免费大全7| 国产美女午夜福利| 久久久久国产网址| 五月玫瑰六月丁香| 女人被狂操c到高潮| 黄色日韩在线| 高清av免费在线| 日韩一区二区三区影片| 高清视频免费观看一区二区 | 亚洲av不卡在线观看| 精品熟女少妇av免费看| or卡值多少钱| 别揉我奶头 嗯啊视频| 亚洲av中文av极速乱| 欧美zozozo另类| 精品国内亚洲2022精品成人| av播播在线观看一区| 一本久久精品| 91狼人影院| 国产一区亚洲一区在线观看| 国产精品伦人一区二区| av.在线天堂| 国产高清国产精品国产三级 | 日韩伦理黄色片| 成年人午夜在线观看视频 | 亚洲激情五月婷婷啪啪| 午夜福利视频精品| 80岁老熟妇乱子伦牲交| 婷婷六月久久综合丁香| 日韩 亚洲 欧美在线| 大香蕉久久网| 777米奇影视久久| 亚洲久久久久久中文字幕| 免费观看在线日韩| 美女xxoo啪啪120秒动态图| 国产亚洲av片在线观看秒播厂 | 欧美另类一区| 99久久人妻综合| 亚洲激情五月婷婷啪啪| 丰满少妇做爰视频| 中国美白少妇内射xxxbb| 最近最新中文字幕免费大全7| 国产视频内射| 国产老妇女一区| 搡老妇女老女人老熟妇| 免费观看精品视频网站| 国产一区二区在线观看日韩| 国产精品久久久久久精品电影小说 | 精品一区二区三区人妻视频| 亚洲av一区综合| 国产色爽女视频免费观看| 美女主播在线视频| 国产成人aa在线观看| 久久久久久久久久人人人人人人| 99久久九九国产精品国产免费| 热99在线观看视频| 午夜激情福利司机影院| 你懂的网址亚洲精品在线观看| 嫩草影院新地址| 国产伦精品一区二区三区四那| 美女国产视频在线观看| 亚洲精品中文字幕在线视频 | 少妇熟女aⅴ在线视频| 一级a做视频免费观看| 天堂影院成人在线观看| eeuss影院久久| 非洲黑人性xxxx精品又粗又长| 天堂中文最新版在线下载 | 黄片wwwwww| 最近的中文字幕免费完整| 精品国产露脸久久av麻豆 | 久热久热在线精品观看| ponron亚洲| 男插女下体视频免费在线播放| 天天一区二区日本电影三级| 国产亚洲午夜精品一区二区久久 | 日本三级黄在线观看| 日本午夜av视频| 亚洲人与动物交配视频| 免费观看在线日韩| 在线观看免费高清a一片| 亚洲性久久影院| 久久久久久国产a免费观看| 免费黄频网站在线观看国产| 久久精品国产自在天天线| 亚洲精品成人av观看孕妇| 身体一侧抽搐| 日韩欧美精品免费久久| 人妻制服诱惑在线中文字幕| 激情五月婷婷亚洲| 国产淫语在线视频| 亚洲国产欧美在线一区| 亚洲av在线观看美女高潮| 美女大奶头视频| 韩国av在线不卡| 永久免费av网站大全| 国语对白做爰xxxⅹ性视频网站| 国产精品.久久久| 18禁在线播放成人免费| 欧美潮喷喷水| av又黄又爽大尺度在线免费看| 日日啪夜夜爽| 久久精品久久久久久噜噜老黄| 少妇熟女欧美另类| 91久久精品电影网| 国语对白做爰xxxⅹ性视频网站| 黄色一级大片看看| 一级二级三级毛片免费看| 免费观看精品视频网站| 亚洲怡红院男人天堂| 午夜精品国产一区二区电影 | 少妇的逼水好多| 日韩av免费高清视频| 国产日韩欧美在线精品| 亚洲伊人久久精品综合| 欧美极品一区二区三区四区| 亚洲欧美精品专区久久| 免费黄色在线免费观看| 22中文网久久字幕| 亚洲av免费高清在线观看| 免费av不卡在线播放| 91在线精品国自产拍蜜月| 亚洲无线观看免费| 久久久久久久午夜电影| 国产探花在线观看一区二区| 国产成人91sexporn| 国产久久久一区二区三区| 看非洲黑人一级黄片| 国产一级毛片在线| 国产一区二区三区av在线| 99热全是精品| 久久久午夜欧美精品| 久久久久精品性色| 中文天堂在线官网| 99久国产av精品国产电影| 国产有黄有色有爽视频| 国模一区二区三区四区视频| 一个人看的www免费观看视频| 久久99热这里只频精品6学生| av在线亚洲专区| 国产精品女同一区二区软件| 色5月婷婷丁香| 狂野欧美激情性xxxx在线观看| 国产激情偷乱视频一区二区| 国产成人福利小说| 国产在线男女| 男女国产视频网站| 久久久久久久久中文| 亚洲精品成人av观看孕妇| 国产乱人视频| 99热6这里只有精品| 国内少妇人妻偷人精品xxx网站| 国产精品美女特级片免费视频播放器| 国产午夜福利久久久久久| 毛片女人毛片| 国内精品美女久久久久久| 在线 av 中文字幕| 欧美xxⅹ黑人| 男人爽女人下面视频在线观看| av.在线天堂| 毛片女人毛片| 国产午夜福利久久久久久| 午夜免费激情av| 寂寞人妻少妇视频99o| 亚洲国产色片| 两个人的视频大全免费| 免费观看的影片在线观看| 一个人看的www免费观看视频| 91在线精品国自产拍蜜月| 国产又色又爽无遮挡免| 黑人高潮一二区| 亚洲人成网站在线播| 午夜福利高清视频| 国产黄片视频在线免费观看| 免费少妇av软件| 久久精品国产自在天天线| 精品欧美国产一区二区三| 国产成人freesex在线| 乱人视频在线观看| 国产午夜精品论理片| 我要看日韩黄色一级片| av在线亚洲专区| 搡老妇女老女人老熟妇| 伊人久久精品亚洲午夜| 少妇猛男粗大的猛烈进出视频 | 亚洲国产日韩欧美精品在线观看| 国产视频首页在线观看| 国产伦理片在线播放av一区| 国产综合精华液| 欧美人与善性xxx| 国产黄色小视频在线观看| 国产成人精品福利久久| 国产精品久久久久久av不卡| 黄色日韩在线| 一级毛片我不卡| 我的老师免费观看完整版| 国产麻豆成人av免费视频| 蜜臀久久99精品久久宅男| 特大巨黑吊av在线直播|