| AVS 66th International Symposium & Exhibition | |
| Advanced Ion Microscopy and Ion Beam Nano-engineering Focus Topic | Thursday Sessions |
| Session HI+NS-ThM |
| Session: | Novel Beam Induced Material Engineering and Nano-Patterning |
| Presenter: | Hideaki Takashima, Kyoto university, Japan |
| Authors: | H. Takashima, Kyoto university, Japan A. Fukuda, Kyoto University, Japan H. Maruya, Kyoto University, Japan T. Tashima, Kyoto University, Japan A. Schell, Central European Institute of Technology, Czech Republic S. Takeuchi, Kyoto University, Japan |
| Correspondent: | Click to Email |
Efficient coupling between single light emitters and photons propagating in single mode fibers has been attractive attention recently for the realization of photonic quantum information devices, such as single photon sources, and quantum phase gates. Toward the realization of these devices, we have developed nanofiber Bragg cavity (NFBC), which is an optical nanofiber embedded in a microcavity in it, using a gallium focused ion beam (FIB) milling system. The NFBC has small mode volume of wavelength size, ultra-wide tunability of the resonant wavelength, and high coupling efficiency (>80%). However, experimentally achieved quality (Q) factors have been still a few hundreds. Here, we report the development of the NFBC using a helium ion microscope (ZEISS “ORION NanoFab”).
Nanofibers are fabricated by heating a single-mode fiber with a ceramic heater and stretching the end of the fiber. The diameter of the nanofibers is reduced to about 300 nm. The helium ion beam is periodically irradiated from the top side of the nanofiber to fabricate Bragg grating. The period at the center of the grating is modified for introducing a defect to be worked as a microcavity.
In order to evaluate the Q factor of the NFBC, we measure a transmission spectrum. The light of a halogen lamp is connected to the one end of the NFBC and the transmitted light is observed with a spectrometer with the resolution of 0.17 nm.
When we measure the transmission spectrum of the NFBC with the grooves of 320, a sharp resonant peak with the linewidth of 0.54 nm was observed in the center of the stop band. This agrees with the Q factor of 1260, which is more than 4 times larger than the NFBC fabricated with the Ga FIB system (Q ~ 300). Taking into account of the resolution of the spectrometer, it is expected that the real Q factor would be higher than this value.
In conclusion, we reported the fabrication of NFBC using the helium microscope. When the number of the grooves is 320, the Q factor is 1260, which is more than 4 times larger than the NFBC fabricated by the Ga FIB system.
Besides this result, we will discuss the NFBC when the number of the grooves is changed and the comparison with finite-difference time-domain (FDTD) simulation.
We acknowledge financial support of the JSPS-KAKENHI (Nos. 21101007, 26220712, 23244079, 25620001, 23740228, 26706007, 26610077, and 16K04918); JST-CREST (JPMJCR1674); and Q-LEAP. A part of this work was supported by “Nanotechnology Platform Project (Nanotechnology Open Facilities in Osaka University)” of Ministry of Education, Culture, Sports, Science and Technology, Japan [F-18-OS-0029].