Spatiially Resolved Spectra of Miicro-Crystals and Nano-Aggiregates in Doped Polymers

1992 ◽  
Vol 290 ◽  
Author(s):  
Duane Birnbaum ◽  
Seong-Keun Kook ◽  
Raoul Kopelman
Keyword(s):  
Spatial Resolution ◽  
Fluorescence Spectra ◽  
Near Field ◽  
Emission Spectra ◽  
Optical Diffraction ◽  
Near Field Optics ◽  
Spatially Resolved ◽  
Doped Polymers ◽  
Doped Polymer ◽  
Near Field Scanning

AbstractNear-field optics techniques make it possible to by-pass the optical diffraction limit (“uncertainty principle) and attain spatial resolution of λ/50 or better. We present near-field scanning optical spectroscopy (NSOS) data on α and ß mixed micro-crystals of perylene and on various aggregates of tetracene doped into PMMA. The spatial resolution is limited by the size of the scanning photon tip and its distance from the sample. We use nanofabricated optical fiber tips (aluminum coated) that are as small as 100 nm. These can be piezoelectrically scanned close to the sample. Fluorescence spectra easily differentiate between adjoining microcrystallites of α and β perylene, giving spectra identical with those of large (>1 cm) single crystals. The apparently homogeneous molecularly doped polymer samples of tetracene/PMMA have regions that fluoresce anywhere between green and red. Thus the spatially resolved spectra are much sharper and more detailed than the broad and featureless bulk spectra. The different emission spectra are attributed to different aggregates of the tetracene guest embedded in the PMMA host

Nano-scale study of microstructure of Eu(DBM)3phen-doped poly(methyl methacrylate) by near-field scanning microscopy and optical properties

2004 ◽  
Vol 19 (8) ◽  
pp. 2256-2261 ◽  
Author(s):  
Hao Liang ◽  
Xiaohong Sun ◽  
Qijin Zhang ◽  
Hai Ming ◽  
Jianhua Cao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Fluorescence Spectra ◽  
Doping Concentration ◽  
Near Field ◽  
Lifetime Measurements ◽  
Spectra Analysis ◽  
Scanning Optical Microscopy ◽  
Doped Polymer ◽  
Near Field Scanning ◽  
The Eu

Eu(DBM)3phen-doped poly(methyl methacryate) (PMMA) with different doping concentration were prepared. The highest doping concentration sample (10000 ppm) was examined by near-field scanning optical microscopy (NSOM) with a resolution of 50 nm; and the result showed that there were no aggregates larger than 50 nm in the doped polymer. This result was further confirmed by optical properties of the doping material. Concentration quenching was not detected by metastable-state lifetime measurements, indicating that no aggregates existed. According to the fluorescence spectra analysis, the relative intensity ratio (R) of 5D0→7F2 to 5D0→7F1 transition was not shown to be significantly changed with the increasing of Eu3+ content. The analysis reflected that the local structure and asymmetry in the vicinity of europium ions were not changed, and that the Eu3+ ions in PMMA were homogeneously dispersed.

scholarly journals Improvement of spatial resolution by tilt correction in near-field scanning microwave microscopy

AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035114
Author(s):  
Xianfeng Zhang ◽  
Zhe Wu ◽  
Quansong Lan ◽  
Zhiliao Du ◽  
Quanxin Zhou ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Near Field ◽  
Tilt Correction ◽  
Microwave Microscopy ◽  
Scanning Microwave Microscopy ◽  
Near Field Scanning

Laser Micro-Machining Using Near-Field Nano-Optics

2004 ◽  
Author(s):  
Haseung Chung ◽  
Katsuo Kurabayashi ◽  
Suman Das
Keyword(s):  
Data Storage ◽  
Near Field ◽  
Numerical Aperture ◽  
Near Field Optics ◽  
Incident Laser Power ◽  
Scanning Optical Microscopy ◽  
Near Field Effect ◽  
Near Field Scanning ◽  
Feature Resolution ◽  
Sub Wavelength

Solid immersion lenses (SIL) facilitate high numerical aperture (NA) and consequent sub-wavelength diffraction limited focusing in near-field optics based systems. Such systems are in commercial and research use for various applications including near-field scanning optical microscopy, ultra-high density magneto-optic data storage and near-field nanolithography. Here, we present a novel nanomanufacturing method using SIL-based near-field optics for laser-induced sub-micron patterning on silicon wafers. The near-field effect of SILs was investigated by using hemispherical BK7 lenses (n=1.5196, NA=0.9237) to superfocus an incident Q-switched, 532nm Nd:YAG laser beam transmitted through a focusing objective. This optical arrangement achieved a laser-processed feature resolution near the diffraction limit in air. Results of experiments that were conducted at various processing conditions to investigate the effects of varying incident laser power (with average pulse power less than 1W), pulse repetition rate, pulse width, number of pulses and size of SIL on processed feature size and resolution are presented.

Nano-Structures Fabrication by Laser Combined with Near-Field Scanning Optical Microscopy

2007 ◽  
Vol 329 ◽  
pp. 415-420
Author(s):  
Dong Jiang Wu ◽  
Juan Zhuang ◽  
Xu Yue Wang ◽  
Ren Ke Kang ◽  
Fu Ling Zhao
Keyword(s):  
Data Storage ◽  
Second Harmonic ◽  
Substrate Surface ◽  
Near Field ◽  
Coupling Efficiency ◽  
Laser Wavelength ◽  
Optical Diffraction ◽  
Storage Device ◽  
Feature Size ◽  
Near Field Scanning

We have developed the laser nanoprocessing technique by the integration of the fs laser and near-field scanning microscopy (NSOM). The second harmonic femtosecond laser working in the optical near-field with the assistance of NSOM equipment was applied to expose the photosensitive polymer material. The nanopatterns with feature size smaller than the laser wavelength can be fabricated. The optical diffraction limitation is therefore broken through by the near-field nanoprocessing. It was found in our experiment that the nanofabrication feature size depends strongly on the gap between the fiber probe tip and the substrate surface, as well as the laser coupling efficiency. The approach offers the advantages of high precision, speed and selectivity in nanopatterning, and is promising to be used in data storage device manufacture for higher density recording.

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.

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