1994 Fiscal Year Final Research Report Summary
Development of a photon scanning tunneling microscope for nondestructive measurements of bio-particles
| Project/Area Number |
05555013
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
OHTSU Motoichi Tokyo Institute of Technology, Interdisciplinary Graduate School of Science and Engineering, Professor, 大学院・総合理工学研究所, 教授 (70114858)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAI Haruo Anritsu Corporation, The 2nd Department, Research Laboratory, Department Head, 第二研究所, 研究部長
TERAMACHI Yasuaki University of Vocational Training, Department of Information Engineering, Profes, 情報工学科, 教授
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| Project Period (FY) |
1993 – 1994
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| Keywords | Optical fiber / Tunneling microscope / Etching / Resolution / Atomic force microscope |
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| Research Abstract |
Fabrication process of an optical fiber probe was developed, which is an essential device for the photon scanning tunneling microscope (PSTM). By extending chemical etching process we have developed previously, the two-step etching was developed. As a result, the cladding diameter was reduced to 1/20 times that of the conventional fiber. By utilizing a high sensitivity of this slender fiber to the atomic force between the probe and sample, a servo-control system was developed to control the sample-probe separation with high accuracy.
The PSTM system was assembled by using this probe and its performance was evaluated. Flagellar filaments of salmonella were used as a reference sample for the evaluation, which has the 25 nm diameter. Collection-mode measurement obtained the image with the resolution of about 5 nm. It was found that the resolution of the image was reduced by increasing the aperture diameter of the probe, and by increasing the sample-probe separation. This dependency agreed
… More
with the theoretical results based on the "virtual photon" model, which we have proposed previously. Futhermore, it was found that the resolution also depended on the polarization-state of the incident light. This dependency was explained based on the spatial distribution of the light-induced polarization on the surface.
To evalute the performance of the illumination-mode PSTM,neurons were used as a reference sample. The bundle of microtubulines (nominal diameter observed by an electron microscope was 25 nm) in the branching axon was successfully imaged without taking them out from the axon. The measured diameter was 25 nm, which is exactly the same as the nominal diameter. From this result, it was confirmed that the present PSTM has the resolution as high as that of the electron microscope for diagnosing biological samples.
Although the experimental results described above was obtained in the air, we have also succeeded in imaging the polyhooks of the flagellar filaments of salmonella in the water. Less
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Research Products
(12 results)
