論文リスト

@article{Murakami:25,

title = {Low-noise quantum frequency conversion with cavity enhancement of the converted mode},

author = {Shoichi Murakami and Toshiki Kobayashi and Shigehito Miki and Hirotaka Terai and Tsuyoshi Kodama and Tsuneaki Sawaya and Akihiko Ohtomo and Hideki Shimoi and Takashi Yamamoto and Rikizo Ikuta},

url = {https://opg.optica.org/opticaq/abstract.cfm?URI=opticaq-3-1-55},

doi = {10.1364/OPTICAQ.542350},

year  = {2025},

date = {2025-01-29},

urldate = {2025-02-01},

journal = {Optica Quantum},

volume = {3},

number = {1},

pages = {55–63},

publisher = {Optica Publishing Group},

abstract = {Quantum frequency conversion (QFC), which converts the frequencies of photons while preserving the quantum state, is an essential technology for realizing the quantum internet and quantum interconnect. In the QFC from the visible to the telecom wavelengths around 1.5 µm, it is widely known that noise photons produced by the strong pump light used for the process contaminate the frequency-converted photon. It degrades the quality of the quantum property of the output photon. Conventional experiments have employed external narrowband frequency filters to eliminate the noise photons. In this study, we present a compact QFC device integrating the cavity structure only for the converted mode. While the cavity structure enhances both the desired efficiency and the noise photon generation, we show that the cavity-enhanced QFC followed by a relatively wide bandpass filter achieves a signal-to-noise ratio (SNR) comparable to conventional systems using external narrowband filters. We experimentally demonstrate the cavity-enhanced QFC for a single photon, converting it from 780 nm to 1540 nm, and successfully observe the non-classical photon statistics after conversion.},

keywords = {quantum frequency conversion, quantum internet},

pubstate = {published},

tppubtype = {article}

}

@article{s24248162c,

title = {Free-Space to SMF Integration and Green to C-Band Conversion Based on PPLN},

author = {Takahiro Kodama and Kiichiro Kuwahara and Ayumu Kariya and Rikizo Ikuta},

url = {https://www.mdpi.com/1424-8220/24/24/8162},

doi = {10.3390/s24248162},

issn = {1424-8220},

year  = {2024},

date = {2024-12-21},

urldate = {2024-12-21},

journal = {Sensors},

volume = {24},

number = {8162},

abstract = {In this study, we experimentally demonstrate a PPLN-based free-space to SMF (single-mode fiber) conversion system capable of efficient long-wavelength down-conversion from 518 nm, optimized for minimal loss in highly turbid water, to 1540 nm, which is ideal for low-loss transmission in standard SMF. Leveraging the nonlinear optical properties of periodically poled lithium niobate (PPLN), we achieve a wavelength conversion efficiency of 1.6% through difference frequency generation while maintaining a received optical signal-to-noise ratio of 10.4 dB. Our findings underscore the potential of integrating PPLN-based wavelength conversion with fiber optic networks, offering a viable solution for next-generation optical sensor systems that demand real-time, low-latency, and reliable data transmission. This work represents a significant advancement in developing robust and efficient optical sensor technologies, addressing the challenges associated with long-distance transmission and broad-linewidth light sources in optical remote sensing applications.},

keywords = {quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{OE494313,

title = {Quantum frequency conversion using 4-port fiber-pigtailed PPLN module},

author = {Shoichi Murakami and Rintaro Fujimoto and Toshiki Kobayashi and Rikizo Ikuta and Asuka Inoue and Takeshi Umeki and Shigehito Miki and Fumihiro China and Hirotaka Terai and Ryoichi Kasahara and Tetsuya Mukai and Nobuyuki Imoto and Takashi Yamamoto },

doi = {10.1364/OE.494313},

year  = {2023},

date = {2023-08-17},

urldate = {2023-08-17},

journal = {Optics Express},

volume = {31},

issue = {18},

pages = {29271-29279},

keywords = {entanglement, quantum frequency conversion, quantum internet},

pubstate = {published},

tppubtype = {article}

}

@article{Ikuta2021,

title = {Cavity-enhanced broadband photonic Rabi oscillation},

author = {Rikizo Ikuta and Toshiki Kobayashi and Tomohiro Yamazaki and Nobuyuki Imoto and Takashi Yamamoto},

url = {https://journals.aps.org/pra/abstract/10.1103/PhysRevA.103.033709},

doi = {https://doi.org/10.1103/PhysRevA.103.033709},

year  = {2021},

date = {2021-03-18},

journal = {Physical Review A},

volume = {103},

pages = {033709},

abstract = {A coherent coupling among different energy photons provided by nonlinear optical interaction is regarded as a photonic version of the Rabi oscillation. Cavity enhancement of the nonlinearity reduces an energy requirement significantly and pushes the scalability of the frequency-encoded photonic circuit based on the photonic Rabi oscillation. However, the confinement of the photons in the cavity severely limits the number of interactable frequency modes. Here we demonstrate a wide-bandwidth and efficient photonic Rabi oscillation achieving full-cycle oscillation based on a cavity-enhanced nonlinear optical interaction with a monolithic integration. We also show its versatile manipulation beyond the frequency degree of freedom such as an all-optical control for polarizing photons with geometric phase. Our results will open up full control accessible to synthetic dimensional photonic systems over wide frequency modes as well as a large-scale photonic quantum information processing.},

keywords = {optical cavity, quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Ikuta2018,

title = {Polarization insensitive frequency conversion for an atom-photon entanglement distribution via a telecom network},

author = {Rikizo Ikuta and Toshiki Kobayashi and Tetsuo Kawakami and Shigehito Miki and Masahiro Yabuno and Taro Yamashita and Hirotaka Terai and Masato Koashi and Tetsuya Mukai and Takashi Yamamoto and Nobuyuki Imoto},

url = {https://www.nature.com/articles/s41467-018-04338-x},

doi = {10.1038/s41467-018-04338-x},

year  = {2018},

date = {2018-05-21},

journal = {Nature Communications},

volume = {9},

pages = {1997},

keywords = {atom, quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Walker2018,

title = {Long-Distance Single Photon Transmission from a Trapped Ion via Quantum Frequency Conversion},

author = {Thomas Walker and Koichiro Miyanishi and Rikizo Ikuta and Hiroki Takahashi and Samir Vartabi Kashanian and Yoshiaki Tsujimoto and Kazuhiro Hayasaka and Takashi Yamamoto and Nobuyuki Imoto and Matthias Keller},

url = {https://doi.org/10.1103/PhysRevLett.120.203601

https://doi.org/10.1103/PhysRevLett.120.203601},

doi = {10.1103/PhysRevLett.120.203601},

year  = {2018},

date = {2018-05-15},

journal = {Phys. Rev. Lett.},

volume = {120},

pages = {203601},

publisher = {American Physical Society},

keywords = {atom, quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Kobayashi:17,

title = {Mach-Zehnder interferometer using frequency-domain beamsplitter},

author = {Toshiki Kobayashi and Daisuke Yamazaki and Kenichiro Matsuki and Rikizo Ikuta and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Takashi Yamamoto and Masato Koashi and Nobuyuki Imoto},

url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-25-10-12052},

doi = {10.1364/OE.25.012052},

year  = {2017},

date = {2017-05-01},

journal = {Opt. Express},

volume = {25},

number = {10},

pages = {12052--12060},

publisher = {OSA},

abstract = {We demonstrate a first-order interference between coherent light at 1580 nm and 795 nm by using a frequency-domain Mach-Zehnder interferometer (MZI). The MZI is implemented by two frequency-domain BSs based on a second-order nonlinear optical effect in a periodically-poled lithium niobate waveguide with a strong pump light. The observed visibility is over 0.99 at 50% conversion efficiencies of the BSs. Toward photonic quantum information processing, sufficiently small background photon rate is necessary. From measurement results with a superconducting single photon detector (SSPD), we discuss the feasibility of the frequency-domain MZI in a quantum regime. Our estimation shows that the single photon interference with the visibility above 0.9 is feasible with practical settings.},

keywords = {quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Ikuta:16,

title = {Heralded single excitation of atomic ensemble via solid-state-based telecom photon detection},

author = {Rikizo Ikuta and Toshiki Kobayashi and Kenichiro Matsuki and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Takashi Yamamoto and Masato Koashi and Tetsuya Mukai and Nobuyuki Imoto},

url = {http://www.osapublishing.org/optica/abstract.cfm?URI=optica-3-11-1279},

doi = {10.1364/OPTICA.3.001279},

year  = {2016},

date = {2016-11-01},

journal = {Optica},

volume = {3},

number = {11},

pages = {1279--1284},

publisher = {OSA},

abstract = {Telecom photonic quantum networks with matter quantum systems enable a rich variety of applications, such as long-distance quantum cryptography and one-way quantum computing. Preparation of a heralded single excitation (HSE) in an atomic ensemble by detecting a telecom wavelength photon having a correlation with the atomic excitation is an important step. Such a system has been demonstrated with a quantum frequency conversion (QFC) to telecom wavelength employing a Rb atomic cloud. However, the limited wavelength selection prevents the next step toward linking various kinds of matter quantum systems through long-distance fiber-based quantum communications. Here we for the first time, demonstrate HSE with a solid-state-based QFC and a detector for a telecom wavelength that will have the great advantage of the utility of mature telecom technologies. We unambiguously show that the demonstrated HSE indicates non-classical statistics by the direct measurement of the autocorrelation function.},

note = {press release by Osaka univ.},

keywords = {atom, quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{kobayashi2016frequency,

title = {Frequency-domain Hong-Ou-Mandel interference},

author = {Toshiki Kobayashi and Rikizo Ikuta and Shuto Yasui and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Takashi Yamamoto and Masato Koashi and Nobuyuki Imoto},

url = {http://qi.mp.es.osaka-u.ac.jp/imotolab/index-j/activity/NP-2016/index.html

https://www.nature.com/articles/nphoton.2016.74},

doi = {10.1038/nphoton.2016.74},

year  = {2016},

date = {2016-04-01},

journal = {Nature Photonics},

volume = {10},

number = {7},

pages = {441},

publisher = {Nature Publishing Group},

note = {press release by Osaka univ. (see "Links")},

keywords = {press, quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Ikuta:14,

title = {Frequency down-conversion of 637 nm light to the telecommunication band for non-classical light emitted from NV centers in diamond},

author = {Rikizo Ikuta and Toshiki Kobayashi and Shuto Yasui and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Mikio Fujiwara and Takashi Yamamoto and Masato Koashi and Masahide Sasaki and Zhen Wang and Nobuyuki Imoto},

url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-22-9-11205},

doi = {10.1364/OE.22.011205},

year  = {2014},

date = {2014-05-01},

journal = {Opt. Express},

volume = {22},

number = {9},

pages = {11205--11214},

publisher = {OSA},

abstract = {We demonstrate a low-noise frequency down-conversion of photons at 637 nm to the telecommunication band at 1587 nm by the difference frequency generation in a periodically-poled lithium niobate. An internal conversion efficiency of the converter is estimated to be 0.44 at the maximum which is achieved by a pump power of 0.43 W, whereas a rate of internal background photons caused by the strong cw pump laser is estimated to be 9 kHz/mW within a bandwidth of about 1 nm. By using the experimental values related to the intrinsic property of the converter, and using the intensity correlation and the average photon number of a 637 nm input light pulse, we derive the intensity correlation of a converted telecom light pulse. Then we discuss feasibility of a single-photon frequency conversion to the telecommunication band for a long-distance quantum communication based on NV centers in diamond.},

keywords = {quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{Ikuta:13,

title = {Observation of two output light pulses from a partial wavelength converter preserving phase of an input light at a single-photon level},

author = {Rikizo Ikuta and Toshiki Kobayashi and Hiroshi Kato and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Mikio Fujiwara and Takashi Yamamoto and Masahide Sasaki and Zhen Wang and Masato Koashi and Nobuyuki Imoto},

url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-21-23-27865},

doi = {10.1364/OE.21.027865},

year  = {2013},

date = {2013-11-01},

journal = {Opt. Express},

volume = {21},

number = {23},

pages = {27865--27872},

publisher = {OSA},

abstract = {We experimentally demonstrate that both of the two output light pulses of different wavelengths from a wavelength converter with various branching ratios preserve phase information of an input light at a single-photon level. In our experiment, we converted temporally-separated two coherent light pulses with average photon numbers of $sim$ 0.1 at 780 nm to light pulses at 1522 nm by using difference-frequency generation in a periodically-poled lithium niobate waveguide. We observed an interference between temporally-separated two modes for both the converted and the unconverted light pulses at various values of the conversion efficiency. We observed interference visibilities greater than 0.88 without suppressing the background noises for any value of the conversion efficiency the wavelength converter achieves. At a conversion efficiency of $sim$ 0.5, the observed visibilities are 0.98 for the unconverted light and 0.99 for the converted light. Such a phase-preserving wavelength converter with high visibilities will be useful for manipulating quantum states encoded in the frequency degrees of freedom.},

keywords = {quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevA.88.042317,

title = {Nonclassical two-photon interference between independent telecommunication light pulses converted by difference-frequency generation},

author = {Rikizo Ikuta and Toshiki Kobayashi and Hiroshi Kato and Shigehito Miki and Taro Yamashita and Hirotaka Terai and Mikio Fujiwara and Takashi Yamamoto and Masato Koashi and Masahide Sasaki and Zhen Wang and Nobuyuki Imoto},

url = {https://link.aps.org/doi/10.1103/PhysRevA.88.042317},

doi = {10.1103/PhysRevA.88.042317},

year  = {2013},

date = {2013-10-01},

journal = {Phys. Rev. A},

volume = {88},

pages = {042317},

publisher = {American Physical Society},

keywords = {quantum frequency conversion},

pubstate = {published},

tppubtype = {article}

}