Effects of a power and photon energy of incident light on near-field etching properties
We developed a near-field etching technique for realizing an ultra-flat surfaces of various materials and structures. To elucidate the near-field etching properties, we have investigated the effects of power and the photon energy of the incident light. First, we established theoretically that an optical near-field with photon energy lower than the absorption edge of the molecules can induce molecular vibrations. We used nanodiamonds to study the power dependence of the near-field etching properties. From the topological changes of the nanodiamonds, we confirmed the linear-dependence of the etching volume with the incident power. Furthermore, we studied the photon energy dependence using TiO2 nanostriped structures, which revealed that a lower photon energy results in a lower etching rate.
The authors wish to express special thanks to Mr. Maiku Yamaguchi (University of Tokyo) for active support and discussion. We thank Mrs. Etsuko Ota (University of Tokyo) for the AFM measurements. This work was partially supported by a MEXT Grant-in-Aid for Scientific Research (B) (No. 26286022, 17H03101), a MEXT Grant-in-Aid for Scientific Research (A) (17H01262), a MEXT Grant-in-Aid for Challenging Research (Exploratory) (No. 17K20091), a MEXT Nanotechnology Platform (No.12024046), Japan (JSPS)-Korea (NRF) Bilateral Program, Japan (JSPS)-France (MAEDI) Bilateral Program SAKURA, the JSPS Core-to-Core Program (A. Advanced Research Networks), JST CREST (No. JPMJCR16N5), MEXT as a social and scientific priority issue (creation of new functional devices and high-performance materials to support next-generation industries) to be tackled using the post-K computer (ID: hp 160204), Nippon Sheet Glass Foundation for Materials Science and Engineering, Iketani Science and Technology Foundation, and Asahi Glass Foundation.
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