| 研究実績の概要 |
In this fiscal year, the main activity was to introduce the terahertz pulses generated by the photoconductive antenna to the scanning probe microscope tip. This step is one of the most critical in order to achieve the goals of this project. As THz light is invisible, a major challenge was how to align the THz light into the STM. As such, effective alignment procedure of the THz light into the tip junction was explored in this year. As a target sample, I used a small gold square deposited on a glass slide. This was chosen as opposed to a large mirror used in the previous year in order to have a sample sensitive to fine alignment. I found that this strategy was effective in achieving a better alignment. Moreover, I found found that the use of motorized mirror mounts was useful to fine tune the alignment. Apart from this protocols for the preparation of the tips was also improved in this year. Moreover, in order to achieve a higher signal, a new lockin amplifier was purchase in this year. With all these steps, a modulated signal based on the oscillation of the SPM tip was observed. With this I can say that I successfully coupled the THz light into the gold tip. After this, I investigated the tip distance dependence and found that it nicely correlates to what is shown in literature.
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| 次年度使用額が生じた理由 |
In the next fiscal year, several remaining parts of the setup will be purchased. This include a new power supply for the emitter, new substrate, materials for tip preparation and some optical components.
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