Realization of a manipulator by a photon scanning tunneling microscope for a single atom crystal growth

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Theory of a photon scanning tunneling microscope (PSTM) was developed by using the concept of a virtual photon. The result agreed well with the experimental results. Although the conventional theories have relied on the electromagnetic wave analysis being difficult for intuitive understanding, it was confirmed that the present theory could overcome this difficulty. Based on this theory, a manipulator was designed for trapping a freely flying single atom in vacuum by an evanescent light emitted from the top of an optical fiber probe for the PSTM. For this design, depth of trapping potential, optimum radius of curvature of the optical fiber probe, and required wavelength of light for about twenty species of atoms were estimated.A method of sharpening the top of the optical fiber probe was developed by using a selective etching technique. The probe with the cone-angle of 15 degree and the radius of curvature smaller than 2 nm was realized. The deviation of the cone-angle was maintained wi … More thin 0.5 degree, by which high reproducibility of this method was confirmed. A method of fabricating a small aperture at the top of the metal-coated sharpened optical fiber probe was also developed.The performances of the PSTM system was improved to increase the measurement speed and resolution. The resultant measurement speed was ten times that of the previous system. The resolution was estimated as 2nm, which is about 10 times higher than that of the conventional system, through the measurements of the bacteriophage T4.Momentum exchange between the evanescent light and rubidium atoms were confirmed by measuring the absorption spectral broadening in rubidium under irradiation of evanescent field. The magnitude of this exchange was sufficiently large for a single rubidium atom trapping. A nonlinear optical wavelength conversion system was designed and preliminary experiments were carried out for realizing 200 - 300 nm wavelength coherent light for the present manipulator combining semiconductor lasers and solid-state lasers.By the present results of study, the present PSTM system was con- firmed to have sufficiently high performances to be used as a manipulator for trapping a single atom. Less