MAPPING OF QUANTUM-HALL EDGE CHANNELS BY A DILUTION-REFRIGERATOR BASED NEAR-FIELD SCANNING OPTICAL MICROSCOPE

2010 ◽  
Vol 19 (04) ◽  
pp. 563-569
Author(s):  
H. ITO ◽  
K. FURUYA ◽  
Y. SHIBATA ◽  
Y. OOTUKA ◽  
S. NOMURA ◽  
...  
Keyword(s):  
Chemical Potential ◽  
Near Field ◽  
Quantum Hall ◽  
Sample Surface ◽  
Optical Microscope ◽  
Optical Probe ◽  
Real Space ◽  
Dilution Refrigerator ◽  
Dimensional Electron Gas ◽  
Near Field Scanning

A real-space mapping of photovoltage near the edge of the Hall-bar of a GaAs/AlGaAs single heterojunction has been obtained using a dilution-refrigerator-based near-field scanning optical microscope in magnetic fields. The optical probe-sample surface distance dependence of photovoltage is investigated. We obtain photovoltage profile in the vicinity of the edge, which reflects the local chemical potential of the two-dimensional electron gas determined by the distribution of the compressible and incompressible strips.

Real-space mapping of compressible and incompressible strips by a near-field scanning optical microscope

2011 ◽  
Author(s):  
H. Ito ◽  
K. Furuya ◽  
Y. Shibata ◽  
Y. Ootuka ◽  
S. Nomura ◽  
...  
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Real Space ◽  
Space Mapping ◽  
Near Field Scanning

Imaging of quantum Hall edge states under quasiresonant excitation by a near-field scanning optical microscope

2013 ◽  
Author(s):  
H. Ito ◽  
Y. Shibata ◽  
S. Mamyoda ◽  
S. Kashiwaya ◽  
M. Yamaguchi ◽  
...  
Keyword(s):  
Near Field ◽  
Quantum Hall ◽  
Optical Microscope ◽  
Edge States ◽  
Near Field Scanning

Extending the Possibilities of Near-Field Scanning Optical Microscopy for Simultaneous Topographical and Chemical Force Imaging

1999 ◽  
Vol 584 ◽  
Author(s):  
N. Nagy ◽  
M. C. Goh
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Microcontact Printing ◽  
Near Field ◽  
Optical Microscope ◽  
Optical Probe ◽  
Germanium Dioxide ◽  
Fiber Optic Probe ◽  
Pure Silica ◽  
Near Field Scanning

AbstractThe Near-field Scanning Optical Microscope (NSOM) is an innovative new form of surface microscopy, which can be used to obtain local spectroscopic information about surfaces, enabling the characterization of nanometer-sized regions. The most important component of this instrument is the scanning probe tip. In this paper, we discuss the production of a novel fiber optic probe that can be used in local spectroscopy with an NSOM, but also for simultaneous imaging of topography and chemical forces. The probe consists of a bent, tapered silicon dioxide optical fiber. We have determined the rates of selective wet chemical etching of germanium dioxide doped pure silica optical fibers and used this information to optimize the probe etching process. A systematic approach for the development and testing of such probes is presented. The performance of the optical probes was characterized using surfaces prepared by the technique of microcontact printing. Phase and friction images of these surfaces were obtained using both standard atomic force microscopy tips and the optical fiber probe. The new optical probe was capable of distinguishing between different chemical regions on the patterned surface.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

EXCITON–PLASMON INTERACTION IN MONOLAYERS OF METAL-SEMICONDUCTOR NANOSTRUCTURES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 623-627 ◽  
Author(s):  
M. HARIDAS ◽  
L. N. TRIPATHI ◽  
J. K. BASU
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Near Field ◽  
Blue Shift ◽  
Optical Microscope ◽  
Peak Position ◽  
Photoluminescence Spectra ◽  
Langmuir Blodgett ◽  
Near Field Scanning ◽  
Cdse Nanorods

Effect of shape and density on the energy transfer between metallic nanoparticles and semi conducting nanostructures was studied by observing the photoluminescence spectra using near field scanning optical microscope. The monolayers of gold nanoparticles, CdSe nanorods and composite with different number ratios were prepared using Langmuir Blodgett method. The spectra collected from the films with different number ratios of CdSe and gold shows a systematic variation of peak position and intensity as a function of number density of CdSe . The photoluminescence spectra collected from composite monolayer is blue shifted compared to the spectra from CdSe nanorods monolayer. Further we observed a blue shift in peak position and reduction emission intensity with respect to increase in the fraction of gold nanoparticles and surface density. We have provided explanation for the observed behavior in terms of strong exciton–plasmon interactions in the compact hybrid monolayers.

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