The Experts below are selected from a list of 115761 Experts worldwide ranked by ideXlab platform
Steven P Denbaars - One of the best experts on this subject based on the ideXlab platform.
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Optical Polarization characteristics of semipolar 3031 and 3031 ingan gan light emitting diodes
Optics Express, 2013Co-Authors: Yuji Zhao, Steven P Denbaars, James S Speck, Qimin Yan, Daniel F Feezell, Kenji Fujito, Chris G Van De Walle, Shuji NakamuraAbstract:Linear polarized electroluminescence was investigated for semipolar (303¯1) and (303¯1¯) InGaN light-emitting diodes (LEDs) with various indium compositions. A high degree of Optical Polarization was observed for devices on both planes, ranging from 0.37 at 438 nm to 0.79 at 519 nm. The extracted valence band energy separation was consistent with the Optical Polarization ratios. The effect of anisotropic strain on the valance band structure was studied using k⋅p method for the above two planes. The theoretical calculations are consistent with the experimental results.
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correlation between Optical Polarization and luminescence morphology of 1122 oriented ingan gan quantum well structures
Applied Physics Express, 2009Co-Authors: Hisashi Masui, Shuji Nakamura, Hirokuni Asamizu, Anurag Tyagi, Natalie Fellows Demille, Steven P DenbaarsAbstract:Quantization effects on Optical Polarization switching in (1122)-oriented InGaN/GaN quantum-well (QW) structures, which were not evident in the previous report by Ueda et al., have been firmly confirmed. The present study found that Polarization ratios became more negative as the luminescence photon energy was decreased from 2.6 eV. Enhancement in Optical Polarization was found in thin QW structures, which is believed to be a result of quantization effects. Sample structures containing thick InGaN and AlGaN layers showed Polarization ratios shifted towards positive values; these samples exhibited in-plane luminescence inhomogeneity with stripe morphologies parallel to [1100] and dark lines appearing at angles between 50 and 62° with respect to [1100].
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Optical Polarization characteristics of m oriented ingan gan light emitting diodes with various indium compositions in single quantum well structure
Journal of Physics D, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Spontaneously polarized light emission from m-plane InGaN/GaN light-emitting diodes was studied as a function of In composition in the InGaN single quantum-well layer. Emission wavelength was varied between 394 and 472 nm. A strong correlation was confirmed between Optical Polarization and In composition; the higher the In composition, the stronger the Optical Polarization. The photon-energy difference between the emission spectra associated with the two Polarizations, ΔM, was evaluated as a function of current. ΔM exhibited a negative monotonic current dependence for the 394 nm emitting sample and the dependence was changed to positive monotonic as the wavelength became longer towards 472 nm. This change was tentatively attributed to the valence band mixing and the crystal momentum conservation that became relevant with the band filling. ΔM and Optical Polarization exhibited only a moderate correlation; the Fermi–Dirac function has been used to explain the weakened Optical Polarization under increased current injection.
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Optical Polarization of m plane in gan gan light emitting diodes characterized via confocal microscope
Physica Status Solidi (a), 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Hirohiko Hirasawa, Natalie N Fellows, James S Speck, Steven P DenbaarsAbstract:A confocal microscope was applied to characterize near-field Optical Polarization of light emission from InGaN-based light-emitting diodes prepared on a nonpolar orientation. Detection of stray light was significantly reduced as a result of the confocal technique compared to broad-area measurements. The confocal measurement required no special sample preparation and obtained data was directly interpretable. A Polarization ratio of 0.83 was measured on long-wavelength emitting devices and was sustained over two orders of magnitude of low current range. Energy shifts and separation of emission peaks for the two Polarization components were evaluated to discuss the valence-band structure. Energy shifts indicated that the topmost band |X 〉 had a heavier effective mass than the lower band |Z 〉. Splitting energy of InGaN was estimated to be 30 meV. Results were consistent with the past reports, thus it was confirmed that the confocal microscope is a valid technique to characterize near-field Optical Polarization. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Optical Polarization characteristics of ingan gan light emitting diodes fabricated on gan substrates oriented between 101 0 and 101 1 planes
Applied Physics Letters, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Optical Polarization characteristics of InGaN∕GaN light-emitting diodes (LEDs) were studied. Light-emitting diode samples were fabricated on four types of GaN substrates near (101¯0) orientation with intentional off-axis cuts of 0°, 5°, 10°, and 27° towards [0001¯]. A confocal microscope was used to characterize the Optical Polarization of electroluminescence at various currents. The highest Polarization ratio of 0.91 was measured on samples fabricated on a 5° off-cut substrate. First moments were calculated on emission spectra to assess emission peak shifts of two Polarization components. We drew a conclusion that substrate off-axis cut is a technique to improve Optical Polarization characteristics of nonpolar-oriented InGaN∕GaN LEDs.
Shuji Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Optical Polarization characteristics of semipolar 3031 and 3031 ingan gan light emitting diodes
Optics Express, 2013Co-Authors: Yuji Zhao, Steven P Denbaars, James S Speck, Qimin Yan, Daniel F Feezell, Kenji Fujito, Chris G Van De Walle, Shuji NakamuraAbstract:Linear polarized electroluminescence was investigated for semipolar (303¯1) and (303¯1¯) InGaN light-emitting diodes (LEDs) with various indium compositions. A high degree of Optical Polarization was observed for devices on both planes, ranging from 0.37 at 438 nm to 0.79 at 519 nm. The extracted valence band energy separation was consistent with the Optical Polarization ratios. The effect of anisotropic strain on the valance band structure was studied using k⋅p method for the above two planes. The theoretical calculations are consistent with the experimental results.
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correlation between Optical Polarization and luminescence morphology of 1122 oriented ingan gan quantum well structures
Applied Physics Express, 2009Co-Authors: Hisashi Masui, Shuji Nakamura, Hirokuni Asamizu, Anurag Tyagi, Natalie Fellows Demille, Steven P DenbaarsAbstract:Quantization effects on Optical Polarization switching in (1122)-oriented InGaN/GaN quantum-well (QW) structures, which were not evident in the previous report by Ueda et al., have been firmly confirmed. The present study found that Polarization ratios became more negative as the luminescence photon energy was decreased from 2.6 eV. Enhancement in Optical Polarization was found in thin QW structures, which is believed to be a result of quantization effects. Sample structures containing thick InGaN and AlGaN layers showed Polarization ratios shifted towards positive values; these samples exhibited in-plane luminescence inhomogeneity with stripe morphologies parallel to [1100] and dark lines appearing at angles between 50 and 62° with respect to [1100].
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Optical Polarization characteristics of m oriented ingan gan light emitting diodes with various indium compositions in single quantum well structure
Journal of Physics D, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Spontaneously polarized light emission from m-plane InGaN/GaN light-emitting diodes was studied as a function of In composition in the InGaN single quantum-well layer. Emission wavelength was varied between 394 and 472 nm. A strong correlation was confirmed between Optical Polarization and In composition; the higher the In composition, the stronger the Optical Polarization. The photon-energy difference between the emission spectra associated with the two Polarizations, ΔM, was evaluated as a function of current. ΔM exhibited a negative monotonic current dependence for the 394 nm emitting sample and the dependence was changed to positive monotonic as the wavelength became longer towards 472 nm. This change was tentatively attributed to the valence band mixing and the crystal momentum conservation that became relevant with the band filling. ΔM and Optical Polarization exhibited only a moderate correlation; the Fermi–Dirac function has been used to explain the weakened Optical Polarization under increased current injection.
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Optical Polarization of m plane in gan gan light emitting diodes characterized via confocal microscope
Physica Status Solidi (a), 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Hirohiko Hirasawa, Natalie N Fellows, James S Speck, Steven P DenbaarsAbstract:A confocal microscope was applied to characterize near-field Optical Polarization of light emission from InGaN-based light-emitting diodes prepared on a nonpolar orientation. Detection of stray light was significantly reduced as a result of the confocal technique compared to broad-area measurements. The confocal measurement required no special sample preparation and obtained data was directly interpretable. A Polarization ratio of 0.83 was measured on long-wavelength emitting devices and was sustained over two orders of magnitude of low current range. Energy shifts and separation of emission peaks for the two Polarization components were evaluated to discuss the valence-band structure. Energy shifts indicated that the topmost band |X 〉 had a heavier effective mass than the lower band |Z 〉. Splitting energy of InGaN was estimated to be 30 meV. Results were consistent with the past reports, thus it was confirmed that the confocal microscope is a valid technique to characterize near-field Optical Polarization. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Optical Polarization characteristics of ingan gan light emitting diodes fabricated on gan substrates oriented between 101 0 and 101 1 planes
Applied Physics Letters, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Optical Polarization characteristics of InGaN∕GaN light-emitting diodes (LEDs) were studied. Light-emitting diode samples were fabricated on four types of GaN substrates near (101¯0) orientation with intentional off-axis cuts of 0°, 5°, 10°, and 27° towards [0001¯]. A confocal microscope was used to characterize the Optical Polarization of electroluminescence at various currents. The highest Polarization ratio of 0.91 was measured on samples fabricated on a 5° off-cut substrate. First moments were calculated on emission spectra to assess emission peak shifts of two Polarization components. We drew a conclusion that substrate off-axis cut is a technique to improve Optical Polarization characteristics of nonpolar-oriented InGaN∕GaN LEDs.
M G Raymer - One of the best experts on this subject based on the ideXlab platform.
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observation of interaction of spin and intrinsic orbital angular momentum of light
Physical Review Letters, 2017Co-Authors: Dashiell L P Vitullo, Cody Leary, Patrick Gregg, Roger A Smith, Dileep V Reddy, Siddharth Ramachandran, M G RaymerAbstract:The interaction of spin and intrinsic orbital angular momentum of light is observed, as evidenced by length-dependent rotations of both spatial patterns and Optical Polarization in a cylindrically symmetric isotropic Optical fiber. Such rotations occur in a straight few-mode fiber when superpositions of two modes with parallel and antiparallel orientation of spin and intrinsic orbital angular momentum (IOAM=2ℏ) are excited, resulting from a degeneracy splitting of the propagation constants of the modes.
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observation of interaction of spin and intrinsic orbital angular momentum of light
Physical Review Letters, 2017Co-Authors: Dashiell L P Vitullo, Cody Leary, Patrick Gregg, Roger A Smith, Dileep V Reddy, Siddharth Ramachandran, M G RaymerAbstract:The interaction of spin and intrinsic orbital angular momentum of light is observed, as evidenced by length-dependent rotations of both spatial patterns and Optical Polarization in a cylindrically symmetric isotropic Optical fiber. Such rotations occur in a straight few-mode fiber when superpositions of two modes with parallel and antiparallel orientation of spin and intrinsic orbital angular momentum ($\mathrm{IOAM}=2\ensuremath{\hbar}$) are excited, resulting from a degeneracy splitting of the propagation constants of the modes.
Hisashi Masui - One of the best experts on this subject based on the ideXlab platform.
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correlation between Optical Polarization and luminescence morphology of 1122 oriented ingan gan quantum well structures
Applied Physics Express, 2009Co-Authors: Hisashi Masui, Shuji Nakamura, Hirokuni Asamizu, Anurag Tyagi, Natalie Fellows Demille, Steven P DenbaarsAbstract:Quantization effects on Optical Polarization switching in (1122)-oriented InGaN/GaN quantum-well (QW) structures, which were not evident in the previous report by Ueda et al., have been firmly confirmed. The present study found that Polarization ratios became more negative as the luminescence photon energy was decreased from 2.6 eV. Enhancement in Optical Polarization was found in thin QW structures, which is believed to be a result of quantization effects. Sample structures containing thick InGaN and AlGaN layers showed Polarization ratios shifted towards positive values; these samples exhibited in-plane luminescence inhomogeneity with stripe morphologies parallel to [1100] and dark lines appearing at angles between 50 and 62° with respect to [1100].
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Optical Polarization characteristics of m oriented ingan gan light emitting diodes with various indium compositions in single quantum well structure
Journal of Physics D, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Spontaneously polarized light emission from m-plane InGaN/GaN light-emitting diodes was studied as a function of In composition in the InGaN single quantum-well layer. Emission wavelength was varied between 394 and 472 nm. A strong correlation was confirmed between Optical Polarization and In composition; the higher the In composition, the stronger the Optical Polarization. The photon-energy difference between the emission spectra associated with the two Polarizations, ΔM, was evaluated as a function of current. ΔM exhibited a negative monotonic current dependence for the 394 nm emitting sample and the dependence was changed to positive monotonic as the wavelength became longer towards 472 nm. This change was tentatively attributed to the valence band mixing and the crystal momentum conservation that became relevant with the band filling. ΔM and Optical Polarization exhibited only a moderate correlation; the Fermi–Dirac function has been used to explain the weakened Optical Polarization under increased current injection.
-
Optical Polarization of m plane in gan gan light emitting diodes characterized via confocal microscope
Physica Status Solidi (a), 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Hirohiko Hirasawa, Natalie N Fellows, James S Speck, Steven P DenbaarsAbstract:A confocal microscope was applied to characterize near-field Optical Polarization of light emission from InGaN-based light-emitting diodes prepared on a nonpolar orientation. Detection of stray light was significantly reduced as a result of the confocal technique compared to broad-area measurements. The confocal measurement required no special sample preparation and obtained data was directly interpretable. A Polarization ratio of 0.83 was measured on long-wavelength emitting devices and was sustained over two orders of magnitude of low current range. Energy shifts and separation of emission peaks for the two Polarization components were evaluated to discuss the valence-band structure. Energy shifts indicated that the topmost band |X 〉 had a heavier effective mass than the lower band |Z 〉. Splitting energy of InGaN was estimated to be 30 meV. Results were consistent with the past reports, thus it was confirmed that the confocal microscope is a valid technique to characterize near-field Optical Polarization. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Optical Polarization characteristics of ingan gan light emitting diodes fabricated on gan substrates oriented between 101 0 and 101 1 planes
Applied Physics Letters, 2008Co-Authors: Hisashi Masui, Hisashi Yamada, Kenji Iso, Shuji Nakamura, Steven P DenbaarsAbstract:Optical Polarization characteristics of InGaN∕GaN light-emitting diodes (LEDs) were studied. Light-emitting diode samples were fabricated on four types of GaN substrates near (101¯0) orientation with intentional off-axis cuts of 0°, 5°, 10°, and 27° towards [0001¯]. A confocal microscope was used to characterize the Optical Polarization of electroluminescence at various currents. The highest Polarization ratio of 0.91 was measured on samples fabricated on a 5° off-cut substrate. First moments were calculated on emission spectra to assess emission peak shifts of two Polarization components. We drew a conclusion that substrate off-axis cut is a technique to improve Optical Polarization characteristics of nonpolar-oriented InGaN∕GaN LEDs.
Dashiell L P Vitullo - One of the best experts on this subject based on the ideXlab platform.
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observation of interaction of spin and intrinsic orbital angular momentum of light
Physical Review Letters, 2017Co-Authors: Dashiell L P Vitullo, Cody Leary, Patrick Gregg, Roger A Smith, Dileep V Reddy, Siddharth Ramachandran, M G RaymerAbstract:The interaction of spin and intrinsic orbital angular momentum of light is observed, as evidenced by length-dependent rotations of both spatial patterns and Optical Polarization in a cylindrically symmetric isotropic Optical fiber. Such rotations occur in a straight few-mode fiber when superpositions of two modes with parallel and antiparallel orientation of spin and intrinsic orbital angular momentum (IOAM=2ℏ) are excited, resulting from a degeneracy splitting of the propagation constants of the modes.
-
observation of interaction of spin and intrinsic orbital angular momentum of light
Physical Review Letters, 2017Co-Authors: Dashiell L P Vitullo, Cody Leary, Patrick Gregg, Roger A Smith, Dileep V Reddy, Siddharth Ramachandran, M G RaymerAbstract:The interaction of spin and intrinsic orbital angular momentum of light is observed, as evidenced by length-dependent rotations of both spatial patterns and Optical Polarization in a cylindrically symmetric isotropic Optical fiber. Such rotations occur in a straight few-mode fiber when superpositions of two modes with parallel and antiparallel orientation of spin and intrinsic orbital angular momentum ($\mathrm{IOAM}=2\ensuremath{\hbar}$) are excited, resulting from a degeneracy splitting of the propagation constants of the modes.