Near-field thermal transport in a nanotip under laser irradiation.
نویسندگان
چکیده
We report on a systematic study of highly enhanced optical field and its induced thermal transport in nanotips under laser irradiation. The effects on electric field distribution caused by curvature radius, tip aspect ratio, and polarization angle of the incident laser are studied. Our Poynting vectors' study clearly shows that when a laser interacts with a metal tip, it is bent around the tip and concentrated under the apex, where extremely high field enhancement appears. This phenomenon is more like a liquid flow being forced/squeezed to go through a narrow channel. As the tip-substrate distance increases, the peak field enhancement decreases exponentially. A shift of field peak position away from the tip axis is observed. For the incident light, only its component along the tip axis direction has a contribution to the electric field enhancement under the tip apex. The optimum tip apex radius for field enhancement is about 9 nm when the half taper angle is 10°. For a tip with a fixed radius of 30 nm, field enhancement increases with the half taper angle when it is less than 25°. The thermal transport inside the nanoscale tungsten tips due to absorption of incident laser light is explored using the finite element method. A small fraction of light penetrates into the tip. As the polarization angle or apex radius increases, the peak apex temperature decreases. The peak apex temperature goes down as the half taper angle increases, even though the mean laser intensity inside the tip increases, revealing a very strong effect of the taper angle on thermal transport.
منابع مشابه
Noncontact sub-10 nm temperature measurement in near-field laser heating.
An extremely focused optical field down to sub-10 nm in an apertureless near-field scanning optical microscope has been used widely in surface nanostructuring and structure characterization. The involved sub-10 nm near-field heating has not been characterized quantitatively due to the extremely small heating region. In this work, we present the first noncontact thermal probing of silicon under ...
متن کاملInfluence of Interface Thermal Resistance on Relaxation Dynamics of Metal-Dielectric Nanocomposite Materials under Ultrafast Pulse Laser Excitation
Nanocomposite materials, including noble metal nanoparticles embedded in a dielectric host medium, are interesting because of their optical properties linked to surface plasmon resonance phenomena. For studding of nonlinear optical properties and/or energy transfer process, these materials may be excited by ultrashort pulse laser with a temporal width varying from some femtoseconds to some hund...
متن کاملOptimization of a nanotip on a surface for the ultrafast probing of propagating surface plasmons.
We theoretically analyze a method for characterizing propagating surface plasmon polaritons (SPPs) on a thin gold film. The SPPs are excited by few-cycle near-infrared pulses using Kretschmann coupling, and a nanotip is used as a local field sensor. This geometry removes the influence of the incident excitation laser from the near fields, and enhances the plasmon electric field strength. Using ...
متن کاملHigh visibility in two-color above-threshold photoemission from tungsten nanotips in a coherent control scheme
In this article, we present coherent control of above-threshold photoemission from a tungsten nanotip achieving nearly perfect modulation. Depending on the pulse delay between fundamental ([Formula: see text]) and second harmonic ([Formula: see text]) pulses of a femtosecond fiber laser at the nanotip, electron emission is significantly enhanced or depressed during temporal overlap. Electron em...
متن کاملMicroscale Spatially Resolved Thermal Response of Si Nanotip to Laser Irradiation
When an external laser illuminates a nanoscale tip, heating effect arises from absorption of light. This thermal phenomenon happens in near-field scanning optical microscopy (NSOM), 5 apertureless NSOM, tip-enhanced Raman spectroscopy (TERS), laser-assisted scanning tunneling microscope (STM)/ atomic force microscope (AFM)-assisted surface modification and nanofabrication, 11 and high density d...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Nanotechnology
دوره 22 7 شماره
صفحات -
تاریخ انتشار 2011