The Experts below are selected from a list of 18279 Experts worldwide ranked by ideXlab platform
Hitoshi Sumiya - One of the best experts on this subject based on the ideXlab platform.
-
enhancing fluorescence excitation and collection from nitrogen vacancy center in Diamond using micro concave mirror
arXiv: Applied Physics, 2018Co-Authors: Dewen Duan, Shinobu Onoda, Junichi Isoya, Hitoshi Sumiya, Vinaya Kumar Kavatamane, Sri Ranjini Arumugam, Ganesh Rahane, Yan-kai Tzeng, Huan-cheng Chang, Gopalakrishnan BalasubramanianAbstract:We experimentally demonstrate a simple and robust optical fibers based method to achieve simultaneously efficient excitation and fluorescence collection from Nitrogen-Vacancy (NV) defects containing micro-Crystalline Diamond. We fabricate a suitable micro-concave (MC) mirror that focuses scattered excitation laser light into the Diamond located at the focal point of the mirror. At the same instance, the mirror also couples the fluorescence light exiting out of the Diamond Crystal in the opposite direction of the optical fiber back into the optical fiber within its light acceptance cone. This part of fluorescence would have been otherwise lost from reaching the detector. Our proof-of-principle demonstration achieves a 25 times improvement in fluorescence collection compared to the case of not using any mirrors. The increase in light collection favors getting high signal-to-noise ratio (SNR) optically detected magnetic resonance (ODMR) signals hence offers a practical advantage in fiber-based NV quantum sensors. Additionally, we compacted the NV sensor system by replacing some bulky optical elements in the optical path with a 1x2 fiber optical coupler in our optical system. This reduces the complexity of the system and provides portability and robustness needed for applications like magnetic endoscopy and remote-magnetic sensing.
-
Enhancing fluorescence excitation and collection from the nitrogen-vacancy center in Diamond through a micro-concave mirror
'AIP Publishing', 2018Co-Authors: Duan Dewen, Junichi Isoya, Hitoshi Sumiya, Vinaya Kumar Kavatamane, Sri Ranjini Arumugam, Ganesh Rahane, Yan-kai Tzeng, Huan-cheng Chang, Onoda Shinobu, Gopalakrishnan BalasubramanianAbstract:We experimentally demonstrate a simple and robust optical fiber based method to achieve simultaneously efficient excitation and fluorescence collection from Nitrogen-Vacancy (NV) defects containing micro-Crystalline Diamond. We fabricate a suitable micro-concave mirror that focuses scattered excitation laser light into the Diamond located at the focal point of the mirror. At the same instance, the mirror also couples the fluorescence light exiting out of the Diamond Crystal in the opposite direction of the optical fiber back into the optical fiber within its light acceptance cone. This part of fluorescence would have been otherwise lost from reaching the detector. Our proof-of-principle demonstration achieves a 25 times improvement in fluorescence collection compared to the case of not using any mirrors. The increase in light collection favors getting high signal-to-noise ratio optically detected magnetic resonance signals and hence offers a practical advantage in fiber-based NV quantum sensors. Additionally, we compacted the NV sensor system by replacing some bulky optical elements in the optical path with a 1 × 2 fiber optical coupler in our optical system. This reduces the complexity of the system and provides portability and robustness needed for applications like magnetic endoscopy and remote-magnetic sensing
-
Hybrid quantum circuit with a superconducting qubit coupled to a spin ensemble
Physical Review Letters, 2011Co-Authors: Y Kubo, A. Dewes, N. Morishita, H. Abe, Shinobu Onoda, Junichi Isoya, Cécile Grezes, Tadashi Umeda, Hitoshi Sumiya, Takeshi OhshimaAbstract:We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy centers in a Diamond Crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare a superposition of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit later on. These results constitute a proof of concept of spin-ensemble based quantum memory for superconducting qubits.
-
super hard Diamond indenter prepared from high purity synthetic Diamond Crystal
Review of Scientific Instruments, 2005Co-Authors: Hitoshi SumiyaAbstract:The Knoop hardness in (001)⟨110⟩ of high-purity synthetic type IIa Diamond Crystal synthesized under high pressure and high temperature is known to be extremely high. Knoop indenters were prepared from the synthetic type IIa Diamonds by taking the tip orientation to the hard Crystal orientation of the Diamonds, i.e., the z axis and the longitudinal direction of the indenter tip are parallel to the ⟨001⟩ and ⟨110⟩ direction of the Crystal, respectively. Numerous indentation tests on Diamond Crystals revealed that the indenter is substantially rigid and has very high performance. The lifetime of the indenter was more than ten times longer than that of the conventional natural Diamond indenter.
-
indentation hardness of nano polyCrystalline Diamond prepared from graphite by direct conversion
Diamond and Related Materials, 2004Co-Authors: Hitoshi Sumiya, Tetsuo IrifuneAbstract:Abstract Indentation hardness of nano-polyCrystalline Diamonds (consisting of fine particles of 10–30 nm size) prepared directly from graphite under high pressure and high temperature conditions were investigated. It was found that a measurable indentation with no cracking can only be formed using the Knoop indenter in a limited loading condition of 2–6 N, and a reliable and accurate measurement is obtained at a load around 4.9 N. The Knoop hardness measurement at the applied load of 4.9 N revealed that some of the nano-polyCrystalline Diamonds obtained at P ≧15 GPa and T ≧2300 °C have extremely high hardness (120–145 GPa), which is equivalent to that in the (001)〈100〉 of the synthetic high-purity (type IIa) Diamond Crystal (116–130 GPa).
Shuichi Satoh - One of the best experts on this subject based on the ideXlab platform.
-
growth rate of high quality large Diamond Crystals
Journal of Crystal Growth, 2002Co-Authors: Hitoshi Sumiya, Naohiro Toda, Shuichi SatohAbstract:Abstract In the Diamond growth by temperature gradient method under high pressure and high temperature, the growth of a high-quality Diamond Crystal without metal inclusions has been investigated. Large high-quality type IIa Diamond Crystals without impurities of 7–8 ct (about 10 mm across) can be grown at a high growth rate of 6–7 mg/h by prolonged maintenance of a high-precision temperature control with an adequate selection of solvent metal and additives. Type Ib Diamond Crystals containing nitrogen impurities can be grown at higher growth rates up to 15 mg/h by using large seed Crystals and adjusting the morphology with temperature control. This large seed method is not applicable for growing a type IIa Diamond Crystal because it is hard to control the Crystal morphology of it.
-
Mechanical properties of synthetic type IIa Diamond Crystal
Diamond and Related Materials, 1997Co-Authors: Hitoshi Sumiya, Naohiro Toda, Shuichi SatohAbstract:Abstract The mechanical behavior of synthetic type IIa Diamond has been investigated by the Knoop hardness measurement and observation of the cleavage surfaces. It was clarified that the Knoop hardness in (100)〈100〉 of synthetic Diamonds increases with decreasing of the nitrogen impurities concentration, and that the synthetic type IIa Diamond, having few nitrogen impurities, has the highest hardness of synthetic Diamonds. In addition, it was found that the Knoop hardness in (100)〈110〉 of synthetic type IIa Diamond is extremely high, and the anisotropy in the hardness of the Diamond is different from those of natural Diamond and synthetic type Ib Diamond. The cleavage surfaces of the synthetic type IIa Diamonds were very smooth and showed remarkably regular cleavage patterns. These results indicate that there are very few impurities and Crystal defects in the synthetic type IIa Diamond, and also suggest that the Diamond has high resistance to plastic flow.
-
Crystalline perfection of high purity synthetic Diamond Crystal
Journal of Crystal Growth, 1997Co-Authors: Hitoshi Sumiya, Naohiro Toda, Yoshiki Nishibayashi, Shuichi SatohAbstract:Crystalline quality of high purity synthetic Diamond Crystals (type IIa) with impurities less than 0.1 ppm grown by a temperature gradient method under high-pressure and high-temperature has been investigated in detail. The Crystal defects and internal strains of the synthetic type IIa Diamonds were studied by double-Crystal X-ray rocking curve measurement, polarizing microscopy, X-ray topography and Raman spectroscopy. The synthetic type IIa Diamonds were found to have high Crystalline quality with fewer Crystal defects, less internal strain and less variation in defects among Crystals than those of natural Diamonds or synthetic type Ib Diamonds. However, in the synthetic type IIa Diamond Crystal some line and plane defects were observed. It was found that by using strain-free and low defect Crystals for the seeds, the line defects (dislocation bundles) could be removed, thereby improving the Crystalline quality of the synthetic type IIa Diamonds.
-
high pressure synthesis of high purity Diamond Crystal
Diamond and Related Materials, 1996Co-Authors: Hitoshi Sumiya, Shuichi SatohAbstract:High-purity type IIa Diamond Crystals of weight 1–2 carats, containing less than 0.1 ppm chemical impurities and few inclusions, have been successfully synthesized by a temperature gradient method at high pressures and temperatures. The concentration of nitrogen impurities in the Diamond Crystals was reduced to less than 0.1 ppm by adding an element of the IVa group to the solvent as a nitrogen getter. The boron impurity concentration was reduced to less than 0.1 ppm by using a high-purity graphite (<1 ppm impurities) as the carbon source. Nickel impurities were avoided by using an Fe-Co alloy system for the solvent. Furthermore, by adding elements which can reduce the formation of carbides such as TiC or ZrC in the solvent, inclusions of the carbide or the solvent metal in the Diamond Crystal were substantially decreased, and consequently good-quality type IIa Diamond Crystals were obtained even at a growth rate as high as 2–3 mg h−1.
Stanislav Stoupin - One of the best experts on this subject based on the ideXlab platform.
-
side bounce beamlines using single reflection Diamond monochromators at cornell high energy synchrotron source
Journal of Synchrotron Radiation, 2021Co-Authors: Stanislav Stoupin, Thomas Krawczyk, D Sagan, A Temnykh, Louisa M Smieska, Arthur R Woll, Jacob Ruff, A Lyndaker, Alan Pauling, Brendan P CroomAbstract:The design and implementation of new beamlines featuring side-bounce (single-reflection) Diamond monochromators at Cornell High Energy Synchrotron Source (CHESS) are described. Undulator radiation is monochromated using an interchangeable set of Diamond Crystal plates reflecting radiation in the horizontal (synchrotron) plane, where each Crystal plate is set to one of the low-index Bragg reflections (111, 220, 311 and 400) in either Bragg or Laue reflection geometries. At the nominal Bragg angle of 18° these reflections deliver monochromated X-rays with photon energies of 9.7, 15.9, 18.65 and 22.5 keV, respectively. An X-ray mirror downstream of the Diamond monochromator is used for rejection of higher radiation harmonics and for initial focusing of the monochromated beam. The characteristics of the X-ray beam entering the experimental station were measured experimentally and compared with the results of simulations. A reasonable agreement is demonstrated. It is shown that the use of selected high-dislocation-density `mosaic' Diamond single-Crystal plates produced using the chemical vapor deposition method yields a few-fold enhancement in the flux density of the monochromated beam in comparison with that delivered by perfect Crystals under the same conditions. At present, the Functional Materials Beamline at CHESS, which is used for time-resolved in situ characterization of soft materials during processing, has been outfitted with the described setup.
-
performance of a beam multiplexing Diamond Crystal monochromator at the linac coherent light source
Review of Scientific Instruments, 2014Co-Authors: Diling Zhu, Stanislav Stoupin, Sergey Terentyev, Yiping Feng, Henrik T Lemke, D M Fritz, Matthieu Chollet, James M Glownia, Roberto Alonsomori, Marcin SikorskiAbstract:A double-Crystal Diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator Crystals are High-Pressure High-Temperature grown type-IIa Diamond Crystal plates with the (111) orientation. The first Crystal has a thickness of ∼100 μm to allow high reflectivity within the Bragg bandwidth and good transmission for the other wavelengths for downstream use. The second Crystal is about 300 μm thick and makes the exit beam of the monochromator parallel to the incoming beam with an offset of 600 mm. Here we present details on the monochromator design and its performance.
-
Novel Diamond X-ray Crystal optics for synchrotrons and X-ray free-electron lasers
Diamond and Related Materials, 2014Co-Authors: Stanislav StoupinAbstract:Abstract The most common applications of Diamond Crystals in X-ray optics are high-heat-load monochromators for synchrotron beamlines and phase retarders for polarization control. Here, less common applications of Diamond at the frontier of X-ray Crystal optics are reviewed and summarized. These include a sub-meV-bandwidth X-ray monochromator with high spectral efficiency [1] and all-Diamond optical assemblies for a beam-multiplexing double-Crystal monochromator at the Linac Coherent Light Source [2]. Also, novel applications for the realization of fully coherent hard X-ray sources are discussed, such as, Diamond Crystal optics for self-seeding of hard X-rays in the Linac Coherent Light Source [3,4] and Bragg mirrors for the highly anticipated X-ray free-electron laser oscillator [5,6]. These examples present Diamond as a material for the next generation of X-ray optics, optics which can provide unique characteristics and capabilities to modern X-ray sources. In addition, details of practical importance on fabrication and characterization methods of Diamond Crystals with the suitable quality are presented.
-
Hybrid Diamond-silicon angular-dispersive x-ray monochromator with 0.25-meV energy bandwidth and high spectral efficiency
Optics express, 2013Co-Authors: Stanislav Stoupin, Yuri Shvyd'ko, Deming Shu, Vladimir Blank, Sergey Terentyev, Sergey N. Polyakov, M.s. Kuznetsov, Ivan Lemesh, Kiran Mundboth, S. CollinsAbstract:We report on the design, implementation, and performance of an x-ray monochromator with ultra-high energy resolution (ΔE/E ≃ 2.7 × 10−8) and high spectral efficiency using x rays with photon energies E ≃ 9.13 keV. The operating principle of the monochromator is based on the phenomenon of angular dispersion in Bragg back-diffraction. The optical scheme of the monochromator is a modification of a scheme reported earlier [Shvyd’ko et al., Phys. Rev. A 84, 053823 (2011)], where a collimator/wavelength selector Si Crystal was replaced with a 100-μm-thick type IIa Diamond Crystal. This modification provides a very-small-energy bandwidth ΔE ≃ 0.25 meV, a 3-fold increase in the aperture of the accepted beam, a reduction in the cumulative angular dispersion rate of x rays emanating from the monochromator for better focusing on a sample, a sufficient angular acceptance matching the angular divergence of an undulator source (≈ 10 μrad), and an improved throughput due to low x-ray absorption in the thin Diamond Crystal. The measured spectral efficiency of the monochromator was ≈ 65% with an aperture of 0.3 × 1 mm2. The performance parameters of the monochromator are suitable for inelastic x-ray spectroscopy with an absolute energy resolution ΔE < 1 meV.
-
design of a Diamond Crystal monochromator for the lcls hard x ray self seeding project
Journal of Physics: Conference Series, 2013Co-Authors: D Shu, Stanislav Stoupin, P Emma, Yuri Shvydko, J Amann, J QuintanaAbstract:As the result of collaborations between the Advanced Photon Source (APS), Argonne National Laboratory, and the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory, we have designed and constructed a Diamond Crystal monochromator for the LCLS hard x-ray self-seeding project. The novel monochromator is ultrahigh-vacuum compatible to meet the LCLS linear accelerator vacuum environmental requirement. A special graphite holder was designed for strain-free mount of the 110-?m thin synthetic Diamond Crystal plate provided by Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM). An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the thin-film Diamond holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Optical encoders, limit switches, and hardware stops are established in the mechanism to ensure system reliability and to meet the accelerator personal and equipment safety interlock requirements. Molybdenum shields are installed in the monochromator to protect the encoders and associated electronics from radiation damage. Mechanical specifications, designs, and preliminary test results of the Diamond monochromator are presented in this paper.
Naohiro Toda - One of the best experts on this subject based on the ideXlab platform.
-
growth rate of high quality large Diamond Crystals
Journal of Crystal Growth, 2002Co-Authors: Hitoshi Sumiya, Naohiro Toda, Shuichi SatohAbstract:Abstract In the Diamond growth by temperature gradient method under high pressure and high temperature, the growth of a high-quality Diamond Crystal without metal inclusions has been investigated. Large high-quality type IIa Diamond Crystals without impurities of 7–8 ct (about 10 mm across) can be grown at a high growth rate of 6–7 mg/h by prolonged maintenance of a high-precision temperature control with an adequate selection of solvent metal and additives. Type Ib Diamond Crystals containing nitrogen impurities can be grown at higher growth rates up to 15 mg/h by using large seed Crystals and adjusting the morphology with temperature control. This large seed method is not applicable for growing a type IIa Diamond Crystal because it is hard to control the Crystal morphology of it.
-
Mechanical properties of synthetic type IIa Diamond Crystal
Diamond and Related Materials, 1997Co-Authors: Hitoshi Sumiya, Naohiro Toda, Shuichi SatohAbstract:Abstract The mechanical behavior of synthetic type IIa Diamond has been investigated by the Knoop hardness measurement and observation of the cleavage surfaces. It was clarified that the Knoop hardness in (100)〈100〉 of synthetic Diamonds increases with decreasing of the nitrogen impurities concentration, and that the synthetic type IIa Diamond, having few nitrogen impurities, has the highest hardness of synthetic Diamonds. In addition, it was found that the Knoop hardness in (100)〈110〉 of synthetic type IIa Diamond is extremely high, and the anisotropy in the hardness of the Diamond is different from those of natural Diamond and synthetic type Ib Diamond. The cleavage surfaces of the synthetic type IIa Diamonds were very smooth and showed remarkably regular cleavage patterns. These results indicate that there are very few impurities and Crystal defects in the synthetic type IIa Diamond, and also suggest that the Diamond has high resistance to plastic flow.
-
Crystalline perfection of high purity synthetic Diamond Crystal
Journal of Crystal Growth, 1997Co-Authors: Hitoshi Sumiya, Naohiro Toda, Yoshiki Nishibayashi, Shuichi SatohAbstract:Crystalline quality of high purity synthetic Diamond Crystals (type IIa) with impurities less than 0.1 ppm grown by a temperature gradient method under high-pressure and high-temperature has been investigated in detail. The Crystal defects and internal strains of the synthetic type IIa Diamonds were studied by double-Crystal X-ray rocking curve measurement, polarizing microscopy, X-ray topography and Raman spectroscopy. The synthetic type IIa Diamonds were found to have high Crystalline quality with fewer Crystal defects, less internal strain and less variation in defects among Crystals than those of natural Diamonds or synthetic type Ib Diamonds. However, in the synthetic type IIa Diamond Crystal some line and plane defects were observed. It was found that by using strain-free and low defect Crystals for the seeds, the line defects (dislocation bundles) could be removed, thereby improving the Crystalline quality of the synthetic type IIa Diamonds.
Chao Fang - One of the best experts on this subject based on the ideXlab platform.
-
the regulating effect of cooling water temperature on the axial growth rate of large single Crystal Diamond under hpht conditions
Journal of Crystal Growth, 2019Co-Authors: Fangbiao Wang, Chunxiao Wang, Liangchao Chen, Longsuo Guo, Chao FangAbstract:Abstract In this work, we use finite element simulations to investigate the influence of cooling water temperature on the axial growth rate of the large single Crystal Diamond with the convex shape catalyst under high pressure and high temperature (HPHT) conditions. The simulation results show that adjusting the axial cooling water temperature can change the axial temperature gradient and the convection velocity in the catalyst, which lead to the different axial growth rate of the Diamond Crystal. The different axial growth rates lead to the change of Crystal morphology. Simulation results are confirmed by our synthesis experiments. Morphology and structural properties of the synthesized Diamonds are characterized by optical microscope and Raman spectrum. This result not only provides a theoretical explanation for the regulation mechanism of cooling water on the axial growth rate of Diamond, more importantly, adjusting the axial cooling water can further improve the morphology of the synthetic Diamond, which is of great guiding significance in the commercial production of Diamond.
-
method to eliminate the surface growth defects of large single Crystal Diamonds an effective solution to improve the utilization rate for commercial production
CrystEngComm, 2016Co-Authors: Xiaopeng Jia, Shishuai Sun, Liangchao Chen, Longsuo Guo, Ning Chen, Chao FangAbstract:In this work, a growth defect with bowl shaped pits has been found to form during the growth of a Diamond, synthesized over a long period of time using the temperature gradient growth (TGG) method under high pressure and high temperature (HPHT) conditions. The experimental results show that the defect arises during the later growth stage of the Diamond synthetic process. In order to explain the formation of the defect, the temperature and convection fields in the later growth state of the catalyst have been analyzed using the finite element method (FEM). The formation mechanism of the growth defect on the Diamond Crystal has been explained accurately by the simulated results and a good agreement has been obtained between the calculated results and the observed experimental data. Exhilaratingly, we propose a simple and efficient method to eliminate growth defects by adjusting the catalyst thickness. This method not only can improve the quality of large single Crystal Diamonds, but also may be helpful in reducing the cost of Diamond cutting in the commercial market.