Characterization of Materials and Devices by Near-Field Scanning Optical Microscopy

1995 ◽  
Vol 406 ◽  
Author(s):  
B. B. Goldberg ◽  
H. F. Ghaemi ◽  
M. S. Ünlü ◽  
W. D. Herzog
Keyword(s):  
Low Temperature ◽  
Optical Microscopy ◽  
Near Field ◽  
Single Mode ◽  
Sample Surface ◽  
High Energy ◽  
Semiconductor Layer ◽  
Photocurrent Spectroscopy ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

AbstractNear field scanning optical microscopy (NSOM) is a recent technique where a tapered single-mode optical fiber probe is scanned over a sample surface at a height of a fraction of the wavelength. The tapered fiber provides a tiny aperture (a, ˜ 70nm) through which light is coupled and can yield resolutions as high as ˜, λ/40. We have used both room and low-temperature NSOM to study the local spectroscopic characteristics of a wide variety of material systems, from quantum dots and wires, to ordered GaInP, to heterojunctions and optoelectronic devices.Low temperature near-field photoluminescence spectroscopy was used to study spectral emission maps of a set of samples of GaInP epilayers with varying degrees of ordering. The samples exhibit two peaks, a low energy (LE) and a high energy (HE) peak. Our data are inconsistent with expectations that the LE peak is due to emission from domain boundaries and alternative models will be discussed. NSOM spectral maps can yield information about the spatial dependence of the local optical matrix elements. NSOM data on the emission mode structure of strained (In, Ga)As quantum well lasers has yielded new information on the source kinks in the light response at high currents, while local photocurrent spectroscopy using the tip as a point source of photons provides analysis of the semiconductor layer composition.

Tapping Mode Near-Field Scanning Optical Microscopy of Molecular Crystals and Thin Films

1999 ◽  
Vol 5 (S2) ◽  
pp. 994-995
Author(s):  
C. Daniel Frisbie ◽  
Andrey Kosterin ◽  
Helena Stadniychuk
Keyword(s):  
Optical Microscopy ◽  
Spatial Resolution ◽  
Laser Light ◽  
Near Field ◽  
Sample Surface ◽  
Reflected Light ◽  
Surface Laser ◽  
Scanning Optical Microscopy ◽  
Diffraction Effects ◽  
Near Field Scanning

The diffraction of visible light limits the spatial resolution in conventional optical microscopy to about 200-300 nm. In near-field scanning optical microscopy (NSOM), resolution is improved by bringing the light source, such as the end of an optical fiber, very close to the sample surface. Laser light coupled into the opposite end of the fiber propagates down the fiber core and is emitted from the aperture of the tip. When the sample is in the near-field(roughly within one tip diameter of the end of the tip), the spatial resolution is essentially equal to the diameter of the aperture at the end of the tip and is not determined by diffraction effects. Two-dimensional imaging is accomplished by raster-scanning the sample underneath the fiber tip and collecting transmitted or reflected light at a photodetector.

Near-Field Scanning Optical Microscopy Studies of Materials and Devices

MRS Bulletin ◽  
1997 ◽  
Vol 22 (8) ◽  
pp. 27-30 ◽  
Author(s):  
J.W.P. Hsu
Keyword(s):  
Optical Microscopy ◽  
Light Source ◽  
Optical Fibers ◽  
Force Feedback ◽  
Near Field ◽  
Single Mode ◽  
Field Zone ◽  
Research Activities ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

Near-field scanning optical microscopy (NSOM) provides a means to study optical and optoelectronic properties of materials at the nanometer scale. The key to achieving resolution higher than the diffraction limit is to place a subwavelength-sized light source—e.g., an aperture—within the near-field zone of the sample. In this case, the area of the sample illuminated is determined by the aperture size and not by the wavelength (see Figure 1). An image can then be formed by moving the sample and light source with respect to each other. While the principle of near-field optics is straightforward, its realization at visible-light wavelengths was not achieved until the invention of scanning-probe techniques in the 1980s. Since Betzig et al. demonstrated in 1991 that bright subwavelength apertures can be made by tapering and metal-coating single-mode optical fibers, research activities involving NSOM have increased tremendously. The later incorporation of shear-force feedback to regulate tip-sample separation adds another strength to NSOM. Using this distance regulation, a topographic image similar to that obtained by a conventional scanning force microscope is acquired simultaneously with the optical image. This provides a way to correlate structural and physical properties at the same sample positions and greatly simplifies interpretation of the NSOM data.

DESIGN AND CONSTRUCTION OF A SHORT-TIP TAPPING-MODE TUNING FORK NEAR-FIELD SCANNING OPTICAL MICROSCOPE

2003 ◽  
Vol 02 (04n05) ◽  
pp. 225-230
Author(s):  
CHIEN-WEN HUANG ◽  
NIEN-HUA LU ◽  
CHIH-YEN CHEN ◽  
CHENG-FENG YU ◽  
TSUNG-SHENG KAO ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Tuning Fork ◽  
Near Field ◽  
Single Mode ◽  
Optical Microscope ◽  
Sensing Element ◽  
Tapping Mode ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning ◽  
Design And Construction

The design and construction of a tapping-mode tuning fork with a short fiber probe as the force sensing element for near-field scanning optical microscopy is reported. This type of near-field scanning optical microscopy provides a stable and high Q factor at the tapping frequency of the tuning fork, and thus gives high quality NSOM and AFM images of samples. We present results obtained by using the short tip tapping-mode tuning fork near-field scanning optical microscopy measurements performed on the endfaces of a single mode telecommunication optical fiber and a silica-based buried channel waveguide.

Near-field scanning optical microscopy nanoprobes

2012 ◽  
Vol 1 (4) ◽  
pp. 313-338 ◽  
Author(s):  
Monika Fleischer
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Sample Surface ◽  
External Electromagnetic Field ◽  
Point Of View ◽  
Image Point ◽  
Full Spectrum ◽  
Small Surface ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

AbstractNear-field scanning optical microscopy (NSOM) is a powerful method for the optical imaging of surfaces with a resolution down to the nanometer scale. By focusing an external electromagnetic field to the subwavelength aperture or apex of a sharp tip, the diffraction limit is avoided and a near-field spot with a size on the order of the aperture or tip diameter can be created. This point light source is used for scanning a sample surface and recording the signal emitted from the small surface area that interacts with the near field of the probe. In tip-enhanced Raman spectroscopy, such a tip configuration can be used as well to record a full spectrum at each image point, from which chemically specific spectral images of the surface can be extracted. In either case, the contrast and resolution of the images depend critically on the properties of the NSOM probe used in the experiment. In this review, an overview of eligible tip properties and different approaches for tailoring specifically engineered NSOM probes is given from a fabrication point of view.

Raman imaging with near‐field scanning optical microscopy

1995 ◽  
Vol 67 (17) ◽  
pp. 2483-2485 ◽  
Author(s):  
C. L. Jahncke ◽  
M. A. Paesler ◽  
H. D. Hallen
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Raman Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

Investigations of liquid crystals and liquid ambients using near-field scanning optical microscopy

1995 ◽  
Vol 61 (1-4) ◽  
pp. 291-294 ◽  
Author(s):  
Patrick J. Moyer ◽  
Stefan Kämmer ◽  
Karsten Walzer ◽  
Michael Hietschold
Keyword(s):  
Liquid Crystals ◽  
Optical Microscopy ◽  
Near Field ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning
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