The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
P. Daniel Dapkus - One of the best experts on this subject based on the ideXlab platform.
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Room temperature operation of VCSEL-pumped photonic Crystal lasers
LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001Co-Authors: Sang-jun Choi, J.d. O'brien, P. Daniel DapkusAbstract:Recently, photonic Crystal Defect lasers with different designs and cavity sizes have been realized. Here we present results on photonic Crystal lasers optically pumped by a vertical cavity surface-emitting laser (VCSEL). This demonstration validates the low threshold potential of these laser elements and suggests a technique for their excitation.
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Lithographic tuning of a two-dimensional photonic Crystal laser array
IEEE Photonics Technology Letters, 2000Co-Authors: O. Painter, J.d. O'brien, A. Husain, A. Scherer, P. Daniel DapkusAbstract:One attraction of photonic Crystals is the ability to control optical device characteristics by lithographically varying the geometry. In this letter, we demonstrate a 10/spl times/10 array of optically pumped two-dimensional (2-D) photonic Crystal Defect lasers with varying lattice parameters. By adjusting the photonic Crystal interhole spacing as well as the hole diameter we are able to tune the laser wavelength from 1500 to 1625 nm on a monolithic InP-InGaAsP wafer. A wavelength resolution of 10 nm from device to device was obtainable, limited by the lithography and etching tolerances of our fabrication method.
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Room temperature photonic Crystal Defect lasers at near-infrared wavelengths in InGaAsP
Journal of Lightwave Technology, 1999Co-Authors: O.j. Painter, J.d. O'brien, A. Husain, A. Scherer, P. Daniel DapkusAbstract:Room temperature lasing from optically pumped single Defects in a two-dimensional (2-D) photonic bandgap (PBG) Crystal is demonstrated. The high-Q optical microcavities are formed by etching a triangular array of air holes into a half-wavelength thick multiquantum-well waveguide. Defects in the 2-D photonic Crystal are used to support highly localized optical modes with volumes ranging from 2 to 3 (/spl lambda//2n)/sup 3/. Lithographic tuning of the air hole radius and the lattice spacing are used to match the cavity wavelength to the quantum-well gain peak, as well as to increase the cavity Q. The Defect lasers were pumped with 10-30 ns pulses of 0.4-1% duty cycle. The threshold pump power was 1.5 mW (/spl ap/500 /spl mu/W absorbed).
Kent D. Choquette - One of the best experts on this subject based on the ideXlab platform.
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Metal-clad photonic Crystal membrane nanolasers
2012 International Conference on Indium Phosphide and Related Materials, 2012Co-Authors: Joshua D. Sulkin, Kent D. ChoquetteAbstract:We report laterally injected photonic Crystal membrane light emitters that are clad on one surface by metal. Light emission from an electrically injected photonic Crystal Defect cavity is reported. Carriers are injected via a lateral diode that is formed in an InGaAsP membrane using ion implantation. The membrane is removed from its native InP substrate and placed on a thin dielectric layer above Au. The Au-coated substrate provides a large index contrast and good thermal conduction. A cavity resonance in the DC electroluminescence and photopumped laser operation are both observed at room temperature.
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Polarization Switching in Vertical-Cavity Surface-Emitting Lasers With Anisotropic Cavity Geometry and Injection
IEEE Photonics Technology Letters, 2012Co-Authors: Ansas M. Kasten, Timothy A. Strand, Kent D. ChoquetteAbstract:Vertical-cavity surface-emitting lasers with anisotropic cavity geometry and current injection capable of bias-dependent polarization switching are demonstrated. A cruciform-shaped photonic Crystal Defect and ion-implanted aperture defines the transverse cavity which is combined with perpendicularly positioned metal contacts for orthogonal electron injection paths. The dominant polarization is determined by the direction of current injection rather than the Crystallographic axes as found in isotropic cavities. In addition to polarization control and switching, this type of laser has potential for a novel digital modulation scheme with low-operating-power and high-extinction ratio. The authors achieve 9-dB switching contrast with switching amplitude, with the modulation speed thermally limited.
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Decimated Photonic Crystal Defect Cavity Lasers
IEEE Journal of Selected Topics in Quantum Electronics, 2011Co-Authors: Antonios V. Giannopoulos, Joshua D. Sulkin, Christopher M. Long, James J. Coleman, Kent D. ChoquetteAbstract:We present the design, fabrication, and characterization of decimated lattice photonic Crystal membrane lasers. Based on our simulated designs, decimated photonic Crystal lattices have reduced number of holes, which enhance the current and heat conductive paths from the optical cavity with a minimal impact on the cavity quality factor and resonance. Our calculations indicate lower operating temperature using the decimation lattice designs. Two decimated cavity designs are demonstrated and compared to conventional photonic Crystal Defect cavity lasers in InP-based membranes. The decimated designs show improved laser performance with a small reduction of measured cavity quality factor. Reduction of the photonic Crystal holes around the Defect cavity to as few as two periods still enables photopumped operation of photonic Crystal Defect lasers. The improvement in the thermal properties is characterized by varying the photopumping duty cycle.
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Approaches for electrical injection into photonic Crystal nanocavities
2010 IEEE Photonics Society Winter Topicals Meeting Series (WTM), 2010Co-Authors: Antonios V. Giannopoulos, Christopher M. Long, James J. Coleman, Varun Verma, Kent D. ChoquetteAbstract:We discuss two approaches for current injected photonic Crystal Defect membrane emitters. A vertical pn junction using spatially selective gain is reported as well transverse pn junctions created using selective ion implantation.
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2-dimensional coherent arrays of photonic Crystal vertical cavity Defect lasers
Conference on Lasers and Electro-Optics 2004. (CLEO)., 2004Co-Authors: J.j. Raftery, A.j. Danner, Kent D. ChoquetteAbstract:We report the first coherently coupled photonic Crystal vertical cavity surface-emitting 2-dimensional laser arrays. The array elements, which are defined by single photonic Crystal Defect apertures, exhibit out-of-phase coupling.
K.a. Atlasov - One of the best experts on this subject based on the ideXlab platform.
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Modeling of Membrane Photonic Crystal Defect Cavities for Semiconductor Quantum Wire Laser Applications
2009Co-Authors: Fredrik Karlsson, K.a. Atlasov, Elyahou KaponAbstract:Modeling of Membrane Photonic Crystal Defect Cavities for Semiconductor Quantum Wire Laser Applications
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Design of High-Q Membrane Photonic Crystal Defect Cavity for Integration with Semiconductor Quantum Wires
2009Co-Authors: K.a. Atlasov, Fredrik Karlsson, Elyahou KaponAbstract:Design of High-Q Membrane Photonic Crystal Defect Cavity for Integration with Semiconductor Quantum Wires
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wavelength and loss splitting in directly coupled photonic Crystal Defect microcavities
Optics Express, 2008Co-Authors: K.a. Atlasov, K F Karlsson, A Rudra, B Dwir, E KaponAbstract:Coupling between photonic-Crystal Defect microcavities is observed to result in a splitting not only of the mode wavelength but also of the modal loss. It is discussed that the characteristics of the loss splitting may have an important impact on the optical energy transfer between the coupled resonators. The loss splitting — given by the imaginary part of the coupling strength — is found to arise from the difference in diffractive out-of-plane radiation losses of the symmetric and the antisymmetric modes of the coupled system. An approach to control the splitting via coupling barrier engineering is presented.
J.d. O'brien - One of the best experts on this subject based on the ideXlab platform.
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Room temperature operation of VCSEL-pumped photonic Crystal lasers
LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001Co-Authors: Sang-jun Choi, J.d. O'brien, P. Daniel DapkusAbstract:Recently, photonic Crystal Defect lasers with different designs and cavity sizes have been realized. Here we present results on photonic Crystal lasers optically pumped by a vertical cavity surface-emitting laser (VCSEL). This demonstration validates the low threshold potential of these laser elements and suggests a technique for their excitation.
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Lithographic tuning of a two-dimensional photonic Crystal laser array
IEEE Photonics Technology Letters, 2000Co-Authors: O. Painter, J.d. O'brien, A. Husain, A. Scherer, P. Daniel DapkusAbstract:One attraction of photonic Crystals is the ability to control optical device characteristics by lithographically varying the geometry. In this letter, we demonstrate a 10/spl times/10 array of optically pumped two-dimensional (2-D) photonic Crystal Defect lasers with varying lattice parameters. By adjusting the photonic Crystal interhole spacing as well as the hole diameter we are able to tune the laser wavelength from 1500 to 1625 nm on a monolithic InP-InGaAsP wafer. A wavelength resolution of 10 nm from device to device was obtainable, limited by the lithography and etching tolerances of our fabrication method.
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Room temperature photonic Crystal Defect lasers at near-infrared wavelengths in InGaAsP
Journal of Lightwave Technology, 1999Co-Authors: O.j. Painter, J.d. O'brien, A. Husain, A. Scherer, P. Daniel DapkusAbstract:Room temperature lasing from optically pumped single Defects in a two-dimensional (2-D) photonic bandgap (PBG) Crystal is demonstrated. The high-Q optical microcavities are formed by etching a triangular array of air holes into a half-wavelength thick multiquantum-well waveguide. Defects in the 2-D photonic Crystal are used to support highly localized optical modes with volumes ranging from 2 to 3 (/spl lambda//2n)/sup 3/. Lithographic tuning of the air hole radius and the lattice spacing are used to match the cavity wavelength to the quantum-well gain peak, as well as to increase the cavity Q. The Defect lasers were pumped with 10-30 ns pulses of 0.4-1% duty cycle. The threshold pump power was 1.5 mW (/spl ap/500 /spl mu/W absorbed).
Jan Nievendick - One of the best experts on this subject based on the ideXlab platform.
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relation between solar cell efficiency and Crystal Defect etching induced by acidic texturization on multiCrystalline silicon material
Solar Energy Materials and Solar Cells, 2012Co-Authors: Jan Nievendick, Martin Zimmer, Floor Souren, Jonas Haunschild, J RentschAbstract:Abstract Acidic texturing of multi Crystalline silicon (mc-Si) wafers often leads to rough surfaces with areas of strong etch attacks which we call trench structures. Particularly at sites containing Crystal Defects such as grain boundaries and dislocations, trench structures are created. These trench structures have often been reported as detrimental to solar cell performance. In this paper, a detailed statistical analysis of the influence of trench structures on solar cell efficiency is carried out. It is shown that their influence on cell efficiency, as well as open circuit voltage, short circuit current and fill factor, is only very minor. The material quality determines the diffusion length of the minority carriers and predominantly impacts the solar cell efficiency. Moreover, it has been established that trench structures do not significantly influence surface roughness and do not lead to shunting losses. However, the statistical model indicates that materials with many Crystal Defects, and thus lower quality and a smoother (and hence more reflecting) texture lead to slightly higher efficiencies compared to solar cells with a rougher texture. The higher efficiency obtained with smoother textures for this kind of material might be caused by the absence of trench structures. Furthermore, it has been found in this work that for these acidic textures, surface roughness correlates to weighted reflection and hence only one of these parameters has to be determined to analyze an acidic texture.