Morshed Monir, Li Ziyuan, Olbricht Benjamin C, Fu Lan, Haque Ahasanul, Li Li, Rifat Ahmmed A, Rahmani Mohsen, Miroshnichenko Andrey E, Hattori Haroldo T
School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2610, Australia.
Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia.
Sci Rep. 2019 Sep 10;9(1):13023. doi: 10.1038/s41598-019-49517-y.
Nano-antennas are replicas of antennas that operate at radio-frequencies, but with considerably smaller dimensions when compared with their radio frequency counterparts. Noble metals based nano-antennas have the ability to enhance photoinduced phenomena such as localized electric fields, therefore-they have been used in various applications ranging from optical sensing and imaging to performance improvement of solar cells. However, such nano-structures can be damaged in high power applications such as heat resisted magnetic recording, solar thermo-photovoltaics and nano-scale heat transfer systems. Having a small footprint, nano-antennas cannot handle high fluences (energy density per unit area) and are subject to being damaged at adequately high power (some antennas can handle just a few milliwatts). In addition, given that nano-antennas are passive devices driven by external light sources, the potential damage of the antennas limits their use with high power lasers: this liability can be overcome by employing materials with high melting points such as chromium (Cr) and tungsten (W). In this article, we fabricate chromium and tungsten nano-antennas and demonstrate that they can handle 110 and 300 times higher fluence than that of gold (Au) counterpart, while the electric field enhancement is not significantly reduced.
纳米天线是在射频频段工作的天线的复制品，但与它们的射频同类天线相比尺寸要小得多。基于贵金属的纳米天线能够增强诸如局部电场等光致现象，因此，它们已被用于从光学传感和成像到太阳能电池性能提升等各种应用中。然而，在诸如耐热磁记录、太阳能热光伏和纳米尺度热传递系统等高功率应用中，这种纳米结构可能会受到损坏。由于占地面积小，纳米天线无法承受高能量通量（单位面积的能量密度），在足够高的功率下会受到损坏（有些天线只能承受几毫瓦）。此外，鉴于纳米天线是由外部光源驱动的无源器件，天线的潜在损坏限制了它们在高功率激光器中的使用：通过使用诸如铬（Cr）和钨（W）等高熔点材料可以克服这一缺点。在本文中，我们制备了铬和钨纳米天线，并证明它们能够承受的能量通量分别比金（Au）纳米天线高110倍和300倍，同时电场增强并没有显著降低。
