共查询到20条相似文献,搜索用时 31 毫秒
1.
A. A. Ezhov S. A. Magnitskii N. S. Maslova D. A. Muzychenko A. A. Nikulin V. I. Panov 《JETP Letters》2005,82(9):599-602
Light scattering by a small protrusion on a metal surface is analyzed within the framework of perturbation theory. Upon normal incidence of a linearly polarized monochromatic wave, slight deviations of the protrusion’s shape from a circularly symmetric one lead to the formation of optical vortices in the near-field region due to resonant excitation of circular surface plasmons. This agrees with the results of scanning near-field optical microscopy experiments revealing distinct spiral patterns in the in-plane near-field intensity distribution for metallized nanostructured polymer substrates. 相似文献
2.
We have developed a near-field optical probe that uses a triangular metallic plate with a three-dimensionally tapered apex as a light source for thermally assisted magnetic recording. Numerical analysis using a finite-element method shows that the size of the optical spot generated at the apex is 15 nm x 20 nm, and the efficiency (defined as the ratio between the power of the optical near field at the surface of the recording medium and that of the incident light) is 15% when the incident light is focused by a lens with a numerical aperture of 0.8. The metallic plate was fabricated on the surface of a quartz slider and used for writing marks on a phase change recording medium. The marks were observed with a scanning electron microscope, and we confirmed that marks with a diameter of 40 nm were successfully written on the medium. 相似文献
3.
虹吸动态化学腐蚀法制备近场光学显微镜光纤探针的研究 总被引:12,自引:1,他引:11
基于虹吸原理 ,设计了一种动态化学腐蚀法的简易装置 ,用于制备近场光学显微镜光纤探针。在一般化学腐蚀法的基础上 ,通过改变虹吸管中水的流向和流速来有效地控制探针锥角和锥长 ,制备出多种形貌的光纤探针。与传统的静态化学腐蚀法相比 ,该法具有重复性高、探针形貌可控、操作方便、实验费用低廉、制备的探针表面光滑等优点。利用该装置 ,成功地制备出针尖尺寸 5 0~ 30 0nm ,针尖锥角在 16°~ 6 5°之间可调的光纤探针。同时 ,选择适当的液位差 ,通过一步腐蚀法制备出针尖尺寸小于 5 0nm ,针尖锥角 12 5°的双锥角光纤探针。并对可能的腐蚀机理进行了探讨。 相似文献
4.
A GaP microlens for collecting laser light was developed in the tip of a near-field probe. It is important to realize a near-field optical probe head with high throughput and a small spot size. The design and fabrication results of the GaP microlens array are described. The most suitable GaP microlens with a probe was calculated as having a 10 μm radius using the two-dimensional finite difference time domain (2-D FDTD) method. The full width half maximum (FWHM) spot size variation and optical power density tolerance were calculated as 157 nm ± 5 nm and 7%, respectively. A spherical GaP microlens was fabricated with a radius of 10 μm by controlling the Cl2/Ar gas mixture ratio. The difference between the theoretical spherical shape and the fabricated GaP microlens was evaluated as 40 nm at peak to valley. The FWHM spot size and optical throughput of the fabricated microlens were measured as 520 nm and 63%, respectively. The microlens was the same as a theoretical lens with a 10 μm radius. The micron-lens array fabrication process for a near-field optical head was demonstrated in this experiment. 相似文献
5.
We demonstrate high-resolution fluorescence imaging of single molecules using near-field scanning optical microscopy (NSOM)
with a tiny aperture probe for two different wavelengths in visible range in the illumination mode of operation. The spatial
resolutions obtained at both excitation wavelengths were almost the same and the highest resolution realized was about 10
nm. To discuss the achievable resolution in aperture NSOM, we also employed a computer simulation by the finite-difference
time-domain method for various aperture sizes and wavelengths. The resolution of 10 nm is predicted to be contributed by the
single peak of localized near-field light around the rim of the aperture. 相似文献
6.
We fabricated axicon microlenses on a single-mode bare optical fiber by using selective chemical etching technique. By varying the concentration and mixture ratios of etching solutions, we could make axicon microlenses with different apex angles (118°, 107° and 90°). We measured the illumination and collection efficiency of these microlenses by both objective-lens imaging and near-field photoluminescence (PL) spectroscopy of semiconductor quantum dots with respect to the distance between the sample and the axicon lens probe. We found that axicons with 118° and 107° [90°] apex angle tend to exhibit the laser focusing spot sizes of about 406 and 478 nm [382 nm] and maintain the high [slightly low] collection PL intensity with the distance between the sample and the axicon probe. 相似文献
7.
A near-field scanning optical microscope has been developed to yield optical images with various gap distances between the probe and the sample surface. The microscope uses an apertureless metallic probe, the position of which is controlled by regulation of the tunneling-electron current from the probe to the sample and by computer-generated bias voltage. Experimental results of near-field optical imaging with the developed microscope at different gap distances are shown. Thirteen images at gap distances of 0 to 500nm demonstrate that the near-field image depends strongly on the gap distance. The imaging characteristics of a near-field imaging system are shown with the spatial-frequency spectra of images. Future investigation of the developed microscope is also discussed. 相似文献
8.
W. Nomura T. Yatsui T. Kawazoe M. Naruse M. Ohtsu 《Applied physics. B, Lasers and optics》2010,100(1):181-187
The distribution dependency of quantum dots was theoretically and experimentally investigated with respect to the basic properties
optical excitation transfer via optical near-field interactions between quantum dots. The effects of three-dimensional structure
and arraying precision of quantum dots on the signal transfer performance were analyzed. In addition, the quantum dot distribution
dependency of the signal transfer performance was experimentally evaluated by using stacked CdSe quantum dots and an optical
near-field fiber probe tip laminated with quantum dots serving as an output terminal, showing good agreement with theory.
These results demonstrate the basic properties of signal transfer via optical near-field interactions and serve as guidelines
for a nanostructure design optimized to attain the desired signal transfer performances. 相似文献
9.
This paper describes a size-dependent electroless plating method to fabricate a new type of probe with a locally decreasing
thickness of metal and a tiny tip size for a combined high resolution shear-force and near-field optical microscope. In this
method, the tip size and decreasing thickness profile, which affect the resolution capabilities of the microscopes, are controlled
by adding a continuous ultrasonic wave with a frequency of 1 MHz to a nickel plating bath. The probe with a tip radius of
curvature of 25 nm was successfully fabricated at an ultrasonic power density of 1.6 W cm−2, its metal thickness gradually decreased from 850 to 20 nm toward the distal tip. 相似文献
10.
T. Yatsui Y. Nakajima W. Nomura M. Ohtsu 《Applied physics. B, Lasers and optics》2006,84(1-2):265-267
We propose a novel method to increase the resolution of imprint lithography by introducing strong localization of the optical
near-field intensity, depending on the mold structure. By optimizing the thickness of the metallic film on a SiO2 line-and-space (LS) mold without a sidewall coating, we confirmed that the optical near-field strongly localizes at the edge
of the mold, using a finite-difference time-domain calculation method. Based on the calculated results, we performed optical
near-field imprint lithography using a mold with metallized (20-nm-thick Al without a sidewall coating) SiO2 LS with a 300-nm half-pitch that was 200-nm deep with illumination using the g-line (λ=436 nm), and obtained features as
narrow as 50 nm wide.
PACS 81.16.Nd; 81.16.Rf 相似文献
11.
J. Ferber U.C. Fischer N. Hagedorn H. Fuchs 《Applied Physics A: Materials Science & Processing》1999,69(6):581-589
An internal reflection mode is introduced for scanning near-field optical microscopy (SNOM) with the tetrahedral tip. A beam
of light is coupled into the tip and the light specularly reflected out of the tip is detected as a photosignal for SNOM.
An auxiliary STM mode is used to control the distance during the scanning process and to record the topography of the sample
simultaneously with the SNOM image. Images were obtained of different metallic samples which show a contrast in the order
of 10% of the total reflected photosignal. In images of metallic samples an inverted contrast is consistently obtained compared
to images previously obtained of comparable samples in a transmission mode. The contrast shows a pronounced dependence on
the polarization of the incident beam with respect to the orientation of the edges of the tip. In the case of gold surfaces,
the photosignal as a function of distance between the tip and the surface shows a pronounced peak in the near-field range
of 0–20 nm which is tentatively attributed to the excitation of surface plasmons on the gold surface. The pronounced near-field
effects and the strong contrast in the near-field images and the resolution well below 50 nm are an indication of a highly
efficient coupling of the incident beam to a local excitation of the tip apex which is essential for the function of the tip
as a probe for SNOM.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 21 October 1999 相似文献
12.
Quantification of intracellular nanoscale macromolecular density distribution is a fundamental aspect to understanding cellular processes. We report a near-field penetrating optical microscopy (NPOM) technique to directly probe the internal nanoscale macromolecular density of biological cells through quantification of intracellular refractive index (RI). NPOM inserts a tapered optical fiber probe to successive depths into an illuminated sample. A 50 nm diameter probe tip collects signal that exhibits a linear relationship with the sample RI at a spatial resolution of approximately 50 nm for biologically relevant measurements, one order of magnitude finer than the Abbe diffraction limit. Live and fixed cell data illustrate the mechanical ability of a 50 nm probe to penetrate biological samples. 相似文献
13.
Silvia Vignolini Francesca Intonti Francesco Riboli Diederik Sybolt Wiersma Laurent Balet Lianhe H. Li Marco Francardi Annamaria Gerardino Andrea Fiore Massimo Gurioli 《Photonics and Nanostructures》2012,10(3):251-255
The insertion of a metal-coated tip on the surface of a photonic crystal microcavity is used for simultaneous near field imaging of electric and magnetic fields in photonic crystal nanocavities, via the radiative emission of embedded semiconductor quantum dots (QD). The photoluminescence intensity map directly gives the electric field distribution, to which the electric dipole of the QD is coupled. The magnetic field generates, via Faraday's law, a circular current in the apex of the metallized probe that can be schematized as a ring. The resulting magnetic perturbation of the photonic modes induces a blue shift, which can be used to map the magnetic field, within a single near-field scan. 相似文献
14.
Toshiyuki Honda Mitsuhiro Terakawa Minoru Obara 《Applied physics. B, Lasers and optics》2013,111(1):117-126
The localized enhanced near field on nanostructures has been attracting much attention for a template for size-selective optical trapping (tweezers) beyond the diffraction limit. The near-field optical trapping has mainly been studied using metallic substrates such as Au nanodot pairs, periodic Al nanoslits, nanoapertures on an Au film, etc. In this paper, we newly propose a Mie-scattered-near-field optical trapping scheme for size-selective photocatalytic application using pairs of poly-rutile TiO2 nanospheres. The optical intensity distribution in a 3D-nanogap space between the nanospheres was simulated by a 3D FDTD method. The simulation system consists of the two TiO2 nanospheres placed on a silica substrate in water. The 400-nm excitation laser is used for both the near-field trapping and the photocatalyst excitation. The optical trapping forces were calculated based on the near-field optical intensity distribution. The trapping stiffness for 20-nm polystyrene sphere at a gap distance of 20 nm was 6.4 pN/nm/W. The optical force vector shows that the object like virus can be trapped with sufficient forces into the nanogap space and then is driven into the direct surface of the TiO2 sphere. This result suggests that this system works as a photocatalytic trapping for killing virus, protein, etc. 相似文献
15.
Sumio Hosaka Toshimichi Shintani Atsushi Kikukawa Kenchi Itoh 《Applied Surface Science》1999,140(3-4):388-393
We study a nanometer-sized optical probe and image in a scanning near-field optical microscope (SNOM). We demonstrated the potential to observe 5-nm wide optical patterns using the SNOM. The probe profile was measured by using a knife-edge method and a modulated transfer function evaluation method. An aluminum covered and pipet-pulled fiber probe used here has two optical probes, one which has a large diameter of 350 nm and one which has a small diameter of around 10 nm. 相似文献
16.
基于液压传递原理,设计出一种用动态化学腐蚀法制备大锥角近场光纤探针的装置.实验结果表明,在传统的化学腐蚀法制备光纤探针的过程中,通过控制腐蚀液液面的上升速度,可以有效地控制探针针尖的形状以及锥角的大小.在此基础上,还论述了分步控制光纤与腐蚀液液面的相对位移的方法在大锥角光纤探针的制备中所具有的独特优越性.利用所制备的大锥角近场光纤探针在扫描近场光学显微镜上对直径为200nm的小球进行探测,其力学像证实该探针具有较高的形貌分辨率(约为50nm).
关键词:
动态化学腐蚀法
大锥角
近场光纤探针 相似文献
17.
Realization of a near-field optical virtual probe based on an evanescent Bessel beam is strongly dependent on a radially polarized
beam; this makes it essential to study the focusing property of the beam. In this paper, two experimental setups based on
a fiber device and a liquid crystal device, respectively, are built to generate a radially polarized beam. This beam and an
annular radially polarized beam are focused by means of a high numerical aperture objective and a solid immersion lens (SIL).
Near-field distribution of the focus spot, the evanescent Bessel field, is experimentally measured with a scanning near-field
optical microscope (SNOM). The full width at half maximum (FWHM) of the central peak of the evanescent Bessel field is about
200 nm in the close vicinity of the bottom surface of SIL. This has potential for use as a near-field optical virtual probe. 相似文献
18.
19.
D. A. McL Smith S. A. Williams R. D. Miller R. M. Hochstrasser 《Journal of fluorescence》1994,4(2):137-140
We present an example of the first time-correlated single-photon counting (TCSPC) near-field optical measurement. The aperture size of our prepared aluminun-coated fiber-optic probe was approximately 50 nm, which represents a spatial resolution of ex/7 for our UV measurements. Near-field fluorescence decays of poly(phenylmethyl silane) in solid thin films excited in the range 325–360 nm were obtained and the steady-state excitation spectra compared with the excitation spectral information obtained in the far field. Fluorescence decays showed single exponential lifetimes ranging from 45 to 277 ps, which was dependent on the excitation wavelength and the selected near-field tip. The proximity of the metal-coated tip to the sample may be the reason for the modulation in fluorescence lifetime. 相似文献
20.
A virtual probe is a novel immaterial tip based on the near-field evanescent wave interference and small aperture diffraction, which can be used in near-field high-density optical data storage, nano-lithography, near-field optical imaging and spectral detection, near-field optical manipulation of nano-scale specimen, etc. In this paper, the formation mechanism of the virtual probe is analysed, the evanescent wave interference discussed theoretically, and the sidelobe suppression by small aperture is simulated by the three-dimensional finite-difference time-domain method. The simulation results of the optical distribution of the near-field virtual probe reveal that the transmission efficiency of the virtual probe is 102-104 times higher than that of the nano-aperture metal-coated fibre probe widely used in near-field optical systems. The full width at half maximum of the peak, in other words, the size of virtual probe, is constant whatever the distance in a certain range so that the critical nano-separation control in the near-field system can be relaxed. We give an example of the application of the virtual probe in ultrahigh-density optical data storage. 相似文献