Near-field scanning optical microscopy of photonic crystal nanocavities

Near-field scanning optical microscopy was used to observe high-resolution images of confined modes and photonic bands of planar photonic crystal (PPC) nanocavities fabricated in active InGaAsP material. We have observed the smallest optical cavity modes, which are intentionally produced by fractional edge dislocation high-Q cavity designs. The size of the detected mode was roughly four by three lattice spacings. We have also observed extended dielectric-band modes of the bulk PPC surrounding the nanocavity by geometrically altering the bands in emission range and eliminating localized modes out of the emission range

Photonic bandgap microcavity devices

Modern semiconductor microfabrication techniques can be used to define the high quality optical components needed in nanophotonic integrated circuits. Here we show our work on design, fabrication and characterization of ultrasmall lasers, filters, modulators and waveguides in photonic crystals

Near-field scanning optical microscopy of photonic crystal high-Q nanocavities

Near-field scanning optical microscopy (NSOM) was used to observe high-resolution images of planar photonic crystal nanocavities fabricated in active InGaAsP material. We have observed the smallest optical cavity modes and dielectric band modes

Highly Stable Polymer Coating on Silver Nanoparticles for Efficient Plasmonic Enhancement of Fluorescence

Surface coating of plasmonic nanoparticles is of huge importance to suppress fluorescence quenching in plasmon-enhanced fluorescence sensing. Herein, a one-pot method for synthesizing polymer-coated silver nanoparticles was developed using a functional polymer conjugated with disulfide-containing anchoring groups. The disulfides played a crucial role in covalently bonding polymers to the surface of the silver nanoparticles. The covalent bond enabled the polymer layer to form a long-term stable coating on the silver nanoparticles. The polymer layer coated was adequately thin to efficiently achieve plasmonic enhancement of fluorescence and also thick enough to effectively suppress quenching of fluorescence, achieving a huge net enhancement of fluorescence. The polymer-coated plasmonic nanoparticles are a promising platform for demonstrating highly sensitive biosensing for medical diagnostics

Near-field scanning optical microscopy of photonic crystal high-Q nanocavities

Near-field scanning optical microscopy (NSOM) was used to observe high-resolution images of planar photonic crystal nanocavities fabricated in active InGaAsP material. We have observed the smallest optical cavity modes and dielectric band modes

Examination of changes in BMI during university student health checkups

大学メンタルヘルスの現場において，食事の問題や体重へのこだわりなどを主訴とする学生の相談は多く，摂食障害予備群といわれる摂食障害の発症リスクが高い学生が増加している。大学生においては，学生生活への適応が困難となるケースが多い。A大学では，摂食障害の予防や早期発見に向けて，入学時健康診断の際に身体測定や質問紙による摂食態度や気分の調査を行っている。本研究は，大学生の入学時から4年次までの健康診断の際のBody Mass Index（ BMI），および入学時と4年次に実施した摂食態度調査票とBeck Depression Inventory‒II （BDI-II）の個人情報のないデータを用いて，入学時と4年次の健診結果を検討した。入学時の平均BMI は男子21.2±2.8，女子20.2±2.5であり，BMI 17.5未満の低体重者の割合は男子5.1％，女子10.6％であった。4年次の平均BMI は男子21.5±3.1，女子20.5±2.3であり，BMI 17.5未満の低体重者の割合は男子5.3％，女子7.1％であった。入学時と比較して，4年次の健診で体重変化を認めた学生は少なくなかった。定期検診時は体重変化を認める学生に対して指導を行うことが重要であると思われた。Many consultations with students suffering from aberrant eating behaviors and those worried about their weight are provided at campus mental health clinics. The number of university students who are at high risk for anorexia and are to thought to be potential candidates for an eating disorder is increasing, likely because it is often difficult for university students to adapt to student life. To improve the prevention and early detection of eating disorders, we assessed the change in body mass index (BMI) and prevalence of eating attitudes and depressive symptoms as determined by a questionnaire at health checkups for university students. There were not too many students whose weight had changed greatly at the 4th year health checkup as compared with that at their initial checkup on entering school. It is important to instruct students in whom changes in weight are recognized at periodic health checkups

Photonic crystal nanocavities with quantum well or quantum dot active material

We have investigated the miniaturization of photonic devices for ultimate photon localization, and have demonstrated two-dimensional photonic crystal nanolasers with two important quantum nanostructures-quantum wells (QWs) and quantum dots (QDs). Photonic crystal cavities with QW active material, are simple, but powerful nanolasers to produce intense laser output for signal processing. On the other hand, when located in a high-quality factor (Q) nanocavity, because QD(s) strongly couple with the intense optical field, QD photonic crystal cavities are expected to be good experimental setups to study cavity quantum electrodynamics, in addition to high speed and compact laser sources. Our photonic crystal nanolasers have shown as small thresholds as 0.12mW and 0.22mW for QD-photonic crystal lasers and QW-photonic crystal lasers, respectively, by proper cavity designs and nanofabrication. For QD-photonic crystal lasers, whispering gallery modes in square lattice were used together with coupled cavity designs and, for QW-photonic crystal lasers, quadrapole modes in triangular lattice with fractional edge dislocations were used to produce high-Q modes with small mode volume