C-Arm-Free Minimally Invasive Cervical Pedicle Screw Fixation (MICEPS): A Technical Note

A minimally invasive posterolateral approach designed to avoid the lateral misplacement of midcervical pedicle screws was reported, but there is no technical report that describes this technique without C-arm fluoroscopy. We report the results of a 2.5 years follow-up of a 62-year-old female patient with C4 metastatic breast cancer. The patient suffered from severe neck pain and impending quadriplegia for 2 months after radiation therapy. We performed C-arm-free minimally invasive cervical pedicle screw fixation (MICEPS). The patient was suc-cessfully treated with surgery, and her neck pain was well controlled. She had neither neurological deficits nor neck pain at the final (2.5-year) follow-up. C-arm-free MICEPS is a useful technique; in addition, the sur-geons and staff have no risk of radiation exposure, there is a reduced need for postoperative imaging, and a decreased revision rate can be expected with C-arm-free MICEPS

High-fidelity conversion of photonic quantum information to telecommunication wavelength with superconducting single-photon detectors

We experimentally demonstrate a high-fidelity visible-to-telecommunication wavelength conversion of a photon by using a solid-state-based difference frequency generation. In the experiment, one half of a pico-second visible entangled photon pair at 780 nm is converted to a 1522-nm photon, resulting in the entangled photon pair between 780 nm and 1522 nm. Using superconducting single-photon detectors with low dark count rates and small timing jitters, we selectively observed well-defined temporal modes containing the two photons. We achieved a fidelity of $0.93 \pm 0.04$ after the wavelength conversion, indicating that our solid-state-based scheme can be used for faithful frequency down-conversion of visible photons emitted from quantum memories composed of various media.Comment: 5 pages, 4 figure

Detection-dependent six-photon NOON state interference

NOON state interference (NOON-SI) is a powerful tool to improve the phase sensing precision, and can play an important role in quantum sensing and quantum imaging. However, most of the previous NOON-SI experiments only investigated the center part of the interference pattern, while the full range of the NOON-SI pattern has not yet been well explored.In this Letter, we experimentally and theoretically demonstrate up to six-photon NOON-SI and study the properties of the interference patterns over the full range.The multi-photons were generated at a wavelength of 1584 nm from a PPKTP crystal in a parametric down conversion process.It was found that the shape, the coherence time and the visibility of the interference patterns were strongly dependent on the detection schemes.This experiment can be used for applications which are based on the envelope of the NOON-SI pattern, such as quantum spectroscopy and quantum metrology.Comment: 5 pages, 3 figure

Multi-channel SNSPD system with high detection efficiency at telecommunication wavelength

We developed a four-channel superconducting nanowire single-photon detector system based on a Gifford-McMahon cryocooler. All channels showed a system detection efficiency (at a 100 Hz dark-count rate) higher than 16% at 1550 nm wavelength, and the best channel showed a system DE of 21% and 30% at 1550 nm and 1310 nm wavelength, respectively.Comment: 10 pages, 4 figure