含分枝铜纳米线多孔铝膜的偏振特性

利用二次阳极氧化法制备了具有分枝结构的多孔铝(PAA)模板,并以交流电化学沉积的方法在该模板中合成了分枝状的铜纳米线。用SEM观察样品的形貌结构,用分光光度计测量了样品的透射光谱和偏振光谱。实验结果表明,含分枝状铜纳米线结构的多孔铝膜在近红外光区具有较高的透射率,且得到了14～22 dB的消光比。这种微偏振器件制备方法简单、效率高、造价低,在光电集成领域有着广泛的应用前景。

Polarization Properties of the Porous Anodic Alumina Films with Branched Cu Nanowires

The metal nanowires which have been synthesized by the porous anodic alumina (PAA)templates have excellent wire-grid structures,high transmittance and extinction ratio in the near infrared region.Therefore,the porous alumina with metal nanowires can be used as a near-infrared micropolarizer.Although this kind of micropolarizer has many advantages of smaller volume,simpler fabrication method and higher extinction ratio,its extinction ratio could not meet the requirement of the practical application. Based on the polarization principle of the metal wire-grid polarizer,we have analyzed the polarizing me-chanism of PAA with metal nanowires thoroughly.The reason why PAA films with metal nanowires have the properties of polarization is that the loss mechanisms to the P and S light components are different.Then,the metal nanowires with branched structure have been studied,and it could improve the extinction ratio of this kind of micropolarizers by using this branched structure. PAA alumina templates with branches structure were fabricated by the two-step anodic oxidation processes,and then the branched Cu nanowires were synthesized in the templates by alternating current deposition method.We observed the structure image of the samples by scanning electron microscopy,and measured the transmission spectrum and the polarization spectrum of the samples by the spectrophotometer.The transmittance of the Y-branched PAA template is achieved to 90% in the near infrared region,which means that the Y-branched PAA can also be taken as the template of the micropolarizers in this region.The experiment indicated that,such PAA alumina films with branched Cu nanowires have better transmittance in the near infrared region,and an extinction ratio of 14～22 dB was obtained in this region.Owing to the simple processing techniques,the high efficiency and the low cost,this kind of micropolarizer would have a promising future in the field of photoelectricity integration.