Publications by authors named "Hakuta K"

Because dental caries is one of the most preventable diseases in the world, poor oral health and inequitable outcomes are not just a failing of our current system of care and financing, but the result of decades of unjust and oppressive systems that were not designed to serve all patients equitably. Reducing these disparities will take deep and intentional work to focus on value, outcomes, and each patient as a whole person. In this article, we describe some of the unique opportunities funders have to listen, learn, and leverage strategies to redesign the oral health system in a way that prioritizes historically marginalized people and communities and transforms the way oral health care is accessed, delivered, and received.

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Article Synopsis
  • - The study explores how coherent interaction between two sets of resonances in a photonic crystal nanofiber can generate unique resonant effects, including Fano-type resonances and phenomena similar to electromagnetically induced transparency.
  • - These effects result from the mixing of cavity modes with orthogonal polarizations, leading to interactions that create interesting line shapes in the experimental data.
  • - By employing a multiple-mode interaction model, the researchers demonstrate that these spectral characteristics can improve the nanofiber cavity's effectiveness in nanophotonics and quantum applications.
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Recent progress in quantum nanophotonics brings novel ways for manipulating single photons in various nano-waveguides. Among them, one promising approach is to use optical nanofibres (ONFs), tapered optical fibres with sub-wavelength diameter waists. Here, we develop a hybrid system of an ONF and a single quantum dot (QD) operated at cryogenic temperatures.

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Past studies examining the cognitive function of bilingual school-aged children have pointed to enhancements in areas of executive control relative to age-matched monolingual children. The majority of these studies has tested children from a middle-class background and compared performance of bilinguals as a discrete group against monolinguals. The objective of the present study was to determine if cognitive enhancement from bilingualism is sensitive to the child's degree of bilingualism in a sample of eight- and nine-year old Spanish-English bilingual children of low socioeconomic status.

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We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm.

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We report the fabrication of a 1.2 cm long cavity directly on a nanofiber using femtosecond laser ablation. The cavity modes with finesse values in the range of 200-400 can enable the "strong-coupling" regime of cavity QED, with high cooperativity of 10-20, for a single atom trapped 200 nm away from the fiber surface [Phys.

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We demonstrate a method for making precise measurements of the diameter of a tapered optical fiber with a sub-wavelength diameter waist (an optical nanofiber). The essence of the method is to create a composite photonic crystal cavity by mounting a defect-mode grating on an optical nanofiber. The resultant cavity has a resonance wavelength that is sensitive to the nanofiber's diameter, allowing the diameter to be inferred from optical measurements.

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We demonstrate cavity QED conditions in the Purcell regime for single quantum emitters on the surface of an optical nanofiber. The cavity is formed by combining an optical nanofiber and a nanofabricated grating to create a composite photonic crystal cavity. By using this technique, significant enhancement of the spontaneous emission rate into the nanofiber guided modes is observed for single quantum dots.

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We demonstrate the fabrication of photonic crystal (PhC) cavities on optical nanofibers using femtosecond laser ablation. PhC cavities with cavity lengths varying from 0.54 to 3.

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We implemented a photonic crystal nanofiber device by reversibly combining an optical nanofiber and a nanofabricated grating. Using the finite-difference time-domain method, we designed the system for minimal optical loss while tailoring the resonant wavelength and bandwidth of the device. Experimentally, we demonstrated that the combined system shows a strong photonic stop band in good agreement with numerical predictions.

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We demonstrate that thousands of periodic nano-craters are fabricated on a subwavelength-diameter tapered optical fiber, an optical nanofiber, by irradiating with just a single femtosecond laser pulse. A key aspect of the fabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. We also demonstrate that the periodic nano-crater array on the nanofiber shows polarization dependent fiber Bragg grating (FBG) characteristics.

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We experimentally demonstrate the efficient channeling of fluorescence photons from single q dots on optical nanofiber into the guided modes by measuring the photon-count rates through the guided and radiation modes simultaneously. We obtain the maximum channeling efficiency to be 22.0(±4.

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We experimentally investigate the fluorescence photon emission characteristics for single q-dots by using optical nanofibers. We demonstrate that single q-dots can be deposited along an optical nanofiber systematically and reproducibly with a precision of 5 μm. For single q-dots on an optical nanofiber, we measure the fluorescence photon numbers coupled into the nanofiber and the normalized photon correlations, by varying the excitation laser intensity.

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We present the experimental realization of nanofiber Bragg grating (NFBG) by drilling periodic nano-grooves on a subwavelength-diameter silica fiber using focused ion beam milling technique. Using such NFBG structures we have realized nanofiber cavity systems. The typical finesse of such nanofiber cavity is F ∼ 20 - 120 and the on-resonance transmission is ∼ 30 - 80%.

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We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

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We report a steady-state Raman gain measurement of the Q(1)(0) transition (v = 1 ? 0, J = 0 ? 0) in solid parahydrogen. We carry out measurements by pumping with a continuous-wave frequency-doubled YAG laser at 532 nm and observing the direct amplification of a probe-laser beam for the first Stokes transition at 683 nm. A large single-pass amplification coefficient of 2.

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We show that a liquid-hydrogen droplet can achieve high- Q values that exceed 10(9) for whispering-gallery modes in the ultraviolet. We show also that pumping high- Q liquid-hydrogen droplets with ultraviolet laser radiation generates many vibrational and rotational Raman sidebands that cover a broad spectral range from the ultraviolet to the near infrared.

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We experimentally demonstrate efficient coupling of atomic fluorescence to the guided mode of a subwavelength-diameter silica fiber, an optical nanofiber. We show that fluorescence of a very small number of atoms, around the nanofiber can be readily observed through a single-mode optical fiber. We also show that such a technique enables us to probe the van der Waals interaction between atoms and surface with high precision by observing the fluorescence excitation spectrum through the nanofiber.

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An experiment varying the racial (Black, White) and opinion composition in small-group discussions was conducted with college students (N = 357) at three universities to test for effects on the perceived novelty of group members' contributions to discussion and on participants' integrative complexity. Results showed that racial and opinion minorities were both perceived as contributing to novelty. Generally positive effects on integrative complexity were found when the groups had racial- and opinion-minority members and when members reported having racially diverse friends and classmates.

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The critical-period hypothesis for second-language acquisition was tested on data from the 1990 U.S. Census using responses from 2.

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Parametric Raman sideband generation is investigated using strongly driven Raman coherence in solid hydrogen. We show that the Raman coherence prepared with two coaxial single-mode lasers beats with multimode laser radiation with very broad bandwidth and efficiently replicates the broadband nature to the Raman sidebands without the restriction of phase matching. We demonstrate that this efficient replication occurs mainly on the negative side of Raman detuning, where the medium adiabatically follows the antiphased state.

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