Nano-Raman Spectroscopy and Imaging with a Near-Field Scanning Optical Microscope

Author(s):  
C. L. Jahncke ◽  
H. D. Hallen ◽  
M. A. Paesler
2012 ◽  
Author(s):  
Kyoung-Duck Park ◽  
Yong Hwan Kim ◽  
Jin Ho Park ◽  
Jung Su Park ◽  
Young-Hee Lee ◽  
...  

1997 ◽  
Vol 3 (S2) ◽  
pp. 815-816
Author(s):  
M.A. Paesler ◽  
H.D. Hallen ◽  
B.I. Yakobson ◽  
C.J. Jahncke ◽  
P.O. Boykin ◽  
...  

The near-field scanning optical microscope, or NSOM, provides spectroscopists with resolution beneath the diffraction limit. In the NSOM, an optical aperture smaller than the wavelength λ of the probe radiation is scanned in the near-field of a sample. Pixels are serially gathered and then constituted as a computer-generated image. Spectroscopic NSOM investigations demonstrating sub-λ, resolution include studies of photoluminescence, Raman spectroscopy, and single molecule fluorescence. Results of nano-Raman spectroscopy on semiconducting Rb-doped KTP are shown in figure 1. Figure la is a topographic image of the sample showing a square Rb-doped region in an otherwise undoped sample. Figure lc is a NSOM region of the corner of the doped region, and figure lb is an image of the same region taken within a Raman line. While these data do provide sub-λ spectroscopic resolution and other interesting features, the weak signal provided by current NSOM technologies and the low quantum efficiency of the Raman effect necessitated development of a very low-drift microscope and inconveniently long collection times.


Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis

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.


2011 ◽  
Vol 10 (04n05) ◽  
pp. 623-627 ◽  
Author(s):  
M. HARIDAS ◽  
L. N. TRIPATHI ◽  
J. K. BASU

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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