Colossal Absorption of Molecules Inside Single Terahertz Nanoantennas

详细信息    查看全文

• 作者：Hyeong-Ryeol Park ; Kwang Jun Ahn ; Sanghoon Han ; Young-Mi Bahk ; Namkyoo Park ; Dai-Sik Kim
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：April 10, 2013
• 年：2013
• 卷：13
• 期：4
• 页码：1782-1786
• 全文大小：326K
• 年卷期：v.13,no.4(April 10, 2013)
• ISSN：1530-6992

文摘

Molecules have extremely small absorption cross sections in the terahertz range even under resonant conditions, which severely limit their detectability, often requiring tens of milligrams. We demonstrate that nanoantennas tailored for the terahertz range resolves the small molecular cross section problem. The extremely asymmetric electromagnetic environment inside the slot antenna, which finds the electric field being enhanced by thousand times with the magnetic field changed little, forces the molecular cross section to be enhanced by >10³ accompanied by a colossal absorption coefficient of 170鈥?00 cm^鈥?. Tens of nanograms of small molecules such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and lactose drop-cast over an area of 10 mm², with only tens of femtograms of molecules inside the single nanoslot, can readily be detected. Our work enables terahertz sensing of chemical and biological molecules in ultrasmall quantities.

Keywords:

Terahertz nano; terahertz molecule sensing; terahertz absorption; terahertz absorption coefficient; terahertz cross section; terahertz nanoantenna