एक विधि के लिए 3 डी में कट रजत nanostructures को बनाना
Summary
Femtosecond लेजर लेखन प्रत्यक्ष अक्सर पॉलिमर और चश्मे में तीन आयामी (3 डी) पैटर्न बनाने के लिए प्रयोग किया जाता है. हालांकि, 3 डी में patterning धातुओं एक चुनौती बनी हुई है. हम चांदी एक बहुलक मैट्रिक्स एक femtosecond 800 एनएम पर केंद्रित लेजर का उपयोग कर के अंदर एम्बेडेड nanostructures fabricating के लिए एक विधि का वर्णन है.
Abstract
The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.
Protocol
Representative Results
Discussion
प्रक्रिया के लिए महत्वपूर्ण है कि उच्च संकल्प निर्माण की अनुमति देता है एक doped ढांकता हुआ मैट्रिक्स प्राप्त है, लेकिन जल्द ही तैयार करने के बाद नीचा नहीं करता है. PVP, 3 Agno और एच 2 हे का एक साधारण मिश्र?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
हम Amira साथ ऑप्टिकल डेटा के 3 डी प्रतिपादन के लिए पॉल जीएल वेबस्टर को स्वीकार करते हैं. फिल Muñoz और बेंजामिन Franta इसके विकास भर पांडुलिपि पर प्रतिक्रिया प्रदान की है. इस पत्र में वर्णित अनुसंधान FA9550-09-1-+०५४६ अनुदान और FA9550-10-1-0,402 के तहत वैज्ञानिक अनुसंधान की वायु सेना के कार्यालय द्वारा समर्थित किया गया.
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