Masaru Sakai   Yuta Inose   Tomi Ohtsuki   Kazuhiro Ema   Katsumi Kishino   Toshiharu Saiki   
JAPANESE JOURNAL OF APPLIED PHYSICS 53(3) 30301 2014年3月 [査読有り]
The first near-field optical imaging of light localization in a GaN nanocolumn system was performed. The sample used was a randomly arranged GaN nanocolumn with high aspect ratio. We attached an InGaN single quantum well at the apex of each GaN na...
Shuro Izumi   Masahiro Takeoka   Mikio Fujiwara   Nicola Dalla Pozza   Antonio Assalini   Kazuhiro Ema   Masahide Sasaki   
ELEVENTH INTERNATIONAL CONFERENCE ON QUANTUM COMMUNICATION, MEASUREMENT AND COMPUTATION (QCMC) 1633 62-64 2014年 [査読有り]
We propose quantum receivers for 3- and 4-ary phase-shift-keyed (PSK) coherent state signals to overcome the standard quantum limit (SQL). Our receiver, consisting of a displacement operation and on-off detectors with or without feedforward, provi...
Shuro Izumi   Masahiro Takeoka   Kazuhiro Ema   Masahide Sasaki   
PHYSICAL REVIEW A 87(4) 2013年4月 [査読有り]
We propose quantum receivers with optical squeezing and photon-number-resolving detectors (PNRDs) for the near-optimal discrimination of quaternary phase-shift-keyed coherent state signals. The basic scheme is similar to the previous proposals [e....