The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Kunio Yoshida - One of the best experts on this subject based on the ideXlab platform.
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influence of pore volume on laser performance of nd yag ceramics
Journal of Materials Science, 1999Co-Authors: Akio Ikesue, Kunio YoshidaAbstract:For present study, 1.1 at % Nd-doped YAG ceramics with a controlled pore volume (150–930 vol ppm) were fabricated by a solid-state reaction method using high-purity powders. The scattering coefficients of Nd : YAG ceramics, obtained from Fresnel' Equation, increased simply with increases in the pore volume. The cw laser output power of Nd : YAG ceramics was clearly related to the scattering coefficients of the specimens examined in the present works, which in turn were affected on the pore volume. The effective scattering coefficients of Nd : YAG ceramics with a pore volume of ∼150 vol ppm were nearly equivalent to those of a 0.9 at %Nd : YAG single crystal by Czochralski method. As the exciting power was increased under excitation by an 808-nm diode laser, however, the laser output power of the Nd : YAG ceramics exceeded that of the Nd : YAG single crystal because of the fairly large amount of Nd additives. The lasing performance of the Nd : YAG ceramics changed drastically with change in pore volume. On the other hand, lasing performance was not affected by the existence of grain boundaries in the polycrystalline Nd : YAG ceramics.
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Influence of pore volume on laser performance of Nd : YAG ceramics
Journal of Materials Science, 1999Co-Authors: Akio Ikesue, Kunio YoshidaAbstract:For present study, 1.1 at % Nd-doped YAG ceramics with a controlled pore volume (150–930 vol ppm) were fabricated by a solid-state reaction method using high-purity powders. The scattering coefficients of Nd : YAG ceramics, obtained from Fresnel' Equation, increased simply with increases in the pore volume. The cw laser output power of Nd : YAG ceramics was clearly related to the scattering coefficients of the specimens examined in the present works, which in turn were affected on the pore volume. The effective scattering coefficients of Nd : YAG ceramics with a pore volume of ∼150 vol ppm were nearly equivalent to those of a 0.9 at %Nd : YAG single crystal by Czochralski method. As the exciting power was increased under excitation by an 808-nm diode laser, however, the laser output power of the Nd : YAG ceramics exceeded that of the Nd : YAG single crystal because of the fairly large amount of Nd additives. The lasing performance of the Nd : YAG ceramics changed drastically with change in pore volume. On the other hand, lasing performance was not affected by the existence of grain boundaries in the polycrystalline Nd : YAG ceramics.
Alexei E. Zayats - One of the best experts on this subject based on the ideXlab platform.
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Non-minimal Einstein–Maxwell theory: the Fresnel Equation and the Petrov classification of a trace-free susceptibility tensor
Classical and Quantum Gravity, 2018Co-Authors: Alexander B. Balakin, Alexei E. ZayatsAbstract:We construct a classification of dispersion relations for electromagnetic waves non-minimally coupled to space-time curvature, based on analysis of the susceptibility tensor which appears in the non-minimal Einstein–Maxwell theory. We classify solutions to the Fresnel Equation for the model with a trace-free non-minimal susceptibility tensor according to the Petrov scheme. For all Petrov types we discuss specific features of the dispersion relations, and plot the corresponding wave surfaces.
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non minimal einstein maxwell theory the Fresnel Equation and the petrov classification of a trace free susceptibility tensor
Classical and Quantum Gravity, 2018Co-Authors: Alexander B. Balakin, Alexei E. ZayatsAbstract:We construct a classification of dispersion relations for electromagnetic waves non-minimally coupled to space-time curvature, based on analysis of the susceptibility tensor which appears in the non-minimal Einstein–Maxwell theory. We classify solutions to the Fresnel Equation for the model with a trace-free non-minimal susceptibility tensor according to the Petrov scheme. For all Petrov types we discuss specific features of the dispersion relations, and plot the corresponding wave surfaces.
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non minimal einstein maxwell theory the Fresnel Equation and the petrov classification of a trace free susceptibility tensor
arXiv: General Relativity and Quantum Cosmology, 2017Co-Authors: Alexander B. Balakin, Alexei E. ZayatsAbstract:We construct a classification of dispersion relations for the electromagnetic waves non-minimally coupled to the space-time curvature, based on the analysis of the susceptibility tensor, which appears in the non-minimal Einstein-Maxwell theory. We classify solutions to the Fresnel Equation for the model with a trace-free non-minimal susceptibility tensor according to the Petrov scheme. For all Petrov types we discuss specific features of the dispersion relations and plot the corresponding wave surfaces.
Koji Suzuki - One of the best experts on this subject based on the ideXlab platform.
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an absorption based surface plasmon resonance sensor applied to sodium ion sensing based on an ion selective optode membrane
Analytical Chemistry, 2002Co-Authors: Kazuyoshi Kurihara, Kaori Nakamura, Etsuko Hirayama, Koji SuzukiAbstract:A surface plasmon resonance (SPR) sodium ion sensor using an ion optode membrane film was experimentally and theoretically described based on an absorption-based SPR principle proposed in our previous article (Kurihara, K; Suzuki, K. AnaL Chem. 2002, 74, 696-701). The sodium ion concentrations from 10(-6) to 10(-1) have been successfully determined not only by the resonance angle diagnosis of the SPR curve but also by the minimum reflectance one. The ion optode film was plasticized poly(vinyl chloride) including a neutral sodium ionophore, a pH-sensitive cationic dye, and an anionic additive. Its optical absorption intensity changed with the sodium ion concentrations. The SPR ion sensor physically measured the complex refractive index caused by the absorption in the ion optode film. We have exhaustively investigated the experimental response behavior of the SPR curve relative to the sodium ion concentrations by comparison with numerically simulated SPR curves using a three-layer Fresnel Equation including experimental values for the sodium ion optode membrane film. As predicted by the absorption-based SPR principle, the SPR curve behavior of the SPR ion sensors depended on two factors: one was the relation between the excitation frequency of the light source and the absorption maximum frequency in the ion optode film while the other was the gold metallic thickness in the Kretchmann configuration. The concept and practical theory of an absorption-based SPR sensor not only have been proved by the experimental results of the SPR sodium ion sensor but also have successfully allowed flexible ion sensing in an SPR sensor, which would be very difficult without the absorption mechanism in the ion optode film.
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theoretical understanding of an absorption based surface plasmon resonance sensor based on kretchmann s theory
Analytical Chemistry, 2002Co-Authors: Kazuyoshi Kurihara, Koji SuzukiAbstract:An optical-absorption-based surface plasmon resonance (SPR) sensor is proposed, and its theoretical aspects are discussed in terms of mathematical descriptions and numerical simulations of the SPR curve. The response theory of the absorption-based SPR sensing is based on the expansion of Kretchmann's SPR theory into the case in which optical absorption in the sensing layer is expressed by the Lorentz model. The numerical simulations were performed using a three-layer Fresnel Equation of p-polarization. It was found that SPR curve behavior of the absorption-based SPR sensor depends on the frequency relation between the light source and the optical absorption and the thickness of the metal layer. The SPR curve behavior is divided into three types according to the large, small, and equal relations between excitation and absorption frequencies. Each type of behavior is further divided into two types that are due to thin and thick metal layers. The theory of this new type of sensor based on optical absorption ...
Eric Pop - One of the best experts on this subject based on the ideXlab platform.
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Reliably Counting Atomic Planes of Few- Layer Graphene (n > 4)
ACS nano, 2010Co-Authors: Yee Kan Koh, Myungho Bae, David G Cahill, Eric PopAbstract:We demonstrate a reliable technique for counting atomic planes (n) of few-layer graphene (FLG) on SiO2/Si substrates by Raman spectroscopy. Our approach is based on measuring the ratio of the integrated intensity of the G graphene peak and the optical phonon peak of Si,I(G)/I(Si), and is particularly useful in the rangen>4wherefewmethodsexist.Wecompareourresultswithatomicforcemicroscopy(AFM)measurements and Fresnel Equation calculations. Then, we apply our method to unambiguously identifynof FLG devices on SiO2andfind that the mobility (2000 cm 2 V 1 s 1 ) is independent of layer thickness forn>4. Ourfindings suggest that electrical transport in gated FLG devices is dominated by carriers near the FLG/SiO2interface and is thus limited by the environment, even forn>4.
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reliably counting atomic planes of few layer graphene n 4
arXiv: Mesoscale and Nanoscale Physics, 2010Co-Authors: Yee Kan Koh, Myungho Bae, David G Cahill, Eric PopAbstract:We demonstrate a reliable technique for counting atomic planes (n) of few-layer graphene (FLG) on SiO2/Si substrates by Raman spectroscopy. Our approach is based on measuring the ratio of the integrated intensity of the G graphene peak and the optical phonon peak of Si, I(G)/I(Si), and is particularly useful in the range n>4 where few methods exist. We compare our results with atomic force microscopy (AFM) measurements and Fresnel Equation calculations. Lastly, we apply our method to unambiguously identify n of FLG devices and find that the mobility (~2000 cm2 V-1 s-1) is independent of layer thickness for n>4.
Akio Ikesue - One of the best experts on this subject based on the ideXlab platform.
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influence of pore volume on laser performance of nd yag ceramics
Journal of Materials Science, 1999Co-Authors: Akio Ikesue, Kunio YoshidaAbstract:For present study, 1.1 at % Nd-doped YAG ceramics with a controlled pore volume (150–930 vol ppm) were fabricated by a solid-state reaction method using high-purity powders. The scattering coefficients of Nd : YAG ceramics, obtained from Fresnel' Equation, increased simply with increases in the pore volume. The cw laser output power of Nd : YAG ceramics was clearly related to the scattering coefficients of the specimens examined in the present works, which in turn were affected on the pore volume. The effective scattering coefficients of Nd : YAG ceramics with a pore volume of ∼150 vol ppm were nearly equivalent to those of a 0.9 at %Nd : YAG single crystal by Czochralski method. As the exciting power was increased under excitation by an 808-nm diode laser, however, the laser output power of the Nd : YAG ceramics exceeded that of the Nd : YAG single crystal because of the fairly large amount of Nd additives. The lasing performance of the Nd : YAG ceramics changed drastically with change in pore volume. On the other hand, lasing performance was not affected by the existence of grain boundaries in the polycrystalline Nd : YAG ceramics.
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Influence of pore volume on laser performance of Nd : YAG ceramics
Journal of Materials Science, 1999Co-Authors: Akio Ikesue, Kunio YoshidaAbstract:For present study, 1.1 at % Nd-doped YAG ceramics with a controlled pore volume (150–930 vol ppm) were fabricated by a solid-state reaction method using high-purity powders. The scattering coefficients of Nd : YAG ceramics, obtained from Fresnel' Equation, increased simply with increases in the pore volume. The cw laser output power of Nd : YAG ceramics was clearly related to the scattering coefficients of the specimens examined in the present works, which in turn were affected on the pore volume. The effective scattering coefficients of Nd : YAG ceramics with a pore volume of ∼150 vol ppm were nearly equivalent to those of a 0.9 at %Nd : YAG single crystal by Czochralski method. As the exciting power was increased under excitation by an 808-nm diode laser, however, the laser output power of the Nd : YAG ceramics exceeded that of the Nd : YAG single crystal because of the fairly large amount of Nd additives. The lasing performance of the Nd : YAG ceramics changed drastically with change in pore volume. On the other hand, lasing performance was not affected by the existence of grain boundaries in the polycrystalline Nd : YAG ceramics.
