The Experts below are selected from a list of 10275 Experts worldwide ranked by ideXlab platform
Susumu Noda - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of Lasing Modes in double lattice photonic crystal resonators and introduction of in plane heterostructures
Proceedings of the IEEE, 2020Co-Authors: Masahiro Yoshida, Masato Kawasaki, Menaka De Zoysa, Kenji Ishizaki, Takuya Inoue, Yoshinori Tanaka, Ranko Hatsuda, Susumu NodaAbstract:Photonic-crystal surface-emitting lasers (PCSELs) are attractive for a wide range of applications such as material processing and remote sensing owing to their advantage of broad-area coherent Lasing supported by a 2-D photonic crystal. Recently, we proposed double-lattice photonic-crystal resonators and achieved 10-W-class high-power and high-beam-quality (namely, high-brightness) operation. To further increase the brightness, it is important to understand the Lasing Mode behavior of PCSELs in detail. In this article, we experimentally investigate the change in the Lasing Mode depending on the current injection levels and compare the results with a theoretical analysis that accounts for the change in refractive index and gain distributions due to the current injection. We observed a transition from single-Mode Lasing to two-Mode Lasing at high injection currents. We develop a technique for resolving the near-field profiles of individual Lasing Modes and show that these profiles coincide with theoretical predictions. A comparison of experimental and theoretical results reveals that high-order Modes appear due to a bandgap confinement effect induced by a change in the refractive index in the carrier injection area. To effectively remove this confinement effect and suppress the oscillation of high-order Modes, we incorporate an in-plane heterostructure into the PCSEL.
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three dimensional coupled wave analysis for triangular lattice photonic crystal surface emitting lasers with transverse electric polarization
Optics Express, 2013Co-Authors: Yong Liang, Kyosuke Sakai, Kenji Ishizaki, Yoshinori Tanaka, Chao Peng, Seita Iwahashi, Kyoko Kitamura, Susumu NodaAbstract:Three-dimensional coupled-wave theory is extended to Model triangular-lattice photonic-crystal surface-emitting lasers with transverse-electric polarization. A generalized coupled-wave equation is derived to describe the sixfold symmetry of the eigenModes in a triangular lattice. The extended theory includes the effects of both surface radiation and in-plane losses in a finite-size laser structure. Modal properties of interest including the band structure, radiation constant, threshold gain, field intensity profile, and far-field pattern (FFP) are calculated. The calculated band structure and FFP, as well as the predicted Lasing Mode, agree well with experimental observations. The effect of air-hole size on Mode selection is also studied and confirmed by experiment.
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two dimensional coupled wave theory for square lattice photonic crystal lasers with tm polarization
Optics Express, 2007Co-Authors: Kyosuke Sakai, Eiji Miyai, Susumu NodaAbstract:We present a useful framework based on the coupled-wave theory, through which we can survey the resonant Modes of TM polarization in 2D photonic-crystal lasers and understand their properties in detail. Through numerical calculations, we clarify their threshold gains, deviations from the Bragg frequency and field distributions. We find that the Lasing Mode can be selected by manipulating the hole-filling factor or the boundary reflection.
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multidirectionally distributed feedback photonic crystal lasers
Physical Review B, 2002Co-Authors: Masahiro Imada, Alongkarn Chutinan, Susumu Noda, Masamitsu MochizukiAbstract:The Lasing Mode of a two-dimensional (2D) photonic crystal laser with in-plane multidirectionally distributed feedback effect is analyzed theoretically and experimentally. From an investigation of the Bragg diffraction conditions at several points in the photonic band diagram where Lasing is expected, we identify a particular \ensuremath{\Gamma} point at which Lasing occurs due to the coupling of lightwaves propagating in six equivalent \ensuremath{\Gamma}-X directions and diffraction normal to the substrate surface. In order to investigate the Lasing Mode in detail, the distribution of the electromagnetic field at the band edges at the \ensuremath{\Gamma} point is calculated, and each band edge is found to have a different field pattern. The Lasing characteristics of the 2D photonic crystal laser at the Lasing wavelength corresponding to the \ensuremath{\Gamma} point are measured. Single-Mode Lasing over a broad circular area is observed by microelectroluminescence measurements under pulsed conditions at room temperature. We also demonstrate the correspondence between the measured Lasing wavelengths and calculated band edges by comparing the polarization characteristics with the calculated distribution of the electromagnetic field. The results indicate that 2D coherent Lasing oscillation does, in fact, occur due to the multidirectional coupling effect in the 2D photonic crystal. From the theoretical calculation, we show that the polarization patterns of the lasers can be controlled by introducing artificial lattice defects.
Douglas A Stone - One of the best experts on this subject based on the ideXlab platform.
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steady state ab initio laser theory generalizations and analytic results
Physical Review A, 2010Co-Authors: Yidong Chong, Douglas A StoneAbstract:We improve the steady-state ab initio laser theory (SALT) of Tuereci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states that contains the exact threshold Lasing Mode. For cavities with nonuniform index and/or nonuniform gain, the new basis set allows the steady-state Lasing properties to be computed with much greater efficiency. This formulation of the SALT can be solved in the single-pole approximation, which gives the intensities and thresholds, including the effects of nonlinear hole-burning interactions to all orders, with negligible computational effort. The approximation yields a number of analytic predictions, including a 'gain-clamping' transition at which strong modal interactions suppress all higher Modes. We show that the single-pole approximation agrees well with exact SALT calculations, particularly for high-Q cavities. Within this range of validity, it provides an extraordinarily efficient technique for Modeling realistic and complex lasers.
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steady state ab initio laser theory generalizations and analytic results
Physical Review A, 2010Co-Authors: Yidong Chong, Douglas A StoneAbstract:We improve the steady-state ab initio laser theory (SALT) of T\"ureci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states that contains the exact threshold Lasing Mode. For cavities with nonuniform index and/or nonuniform gain, the new basis set allows the steady-state Lasing properties to be computed with much greater efficiency. This formulation of the SALT can be solved in the single-pole approximation, which gives the intensities and thresholds, including the effects of nonlinear hole-burning interactions to all orders, with negligible computational effort. The approximation yields a number of analytic predictions, including a ``gain-clamping'' transition at which strong modal interactions suppress all higher Modes. We show that the single-pole approximation agrees well with exact SALT calculations, particularly for high-$Q$ cavities. Within this range of validity, it provides an extraordinarily efficient technique for Modeling realistic and complex lasers.
Yidong Chong - One of the best experts on this subject based on the ideXlab platform.
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ab initio multiMode linewidth theory for arbitrary inhomogeneous laser cavities
Physical Review A, 2015Co-Authors: Adi Pick, Alexander Cerjan, David Liu, Alejandro W Rodriguez, A D Stone, Yidong Chong, Steven G JohnsonAbstract:We present a multiMode laser-linewidth theory for arbitrary cavity structures and geometries that contains nearly all previously known effects and also finds new nonlinear and multiMode corrections, e.g., a correction to the α factor due to openness of the cavity and a multiMode Schawlow-Townes relation (each linewidth is proportional to a sum of inverse powers of all Lasing Modes). Our theory produces a quantitatively accurate formula for the linewidth, with no free parameters, including the full spatial degrees of freedom of the system. StartingwiththeMaxwell-Blochequations,wehandlequantumandthermalnoisebyintroducingrandomcurrents whose correlations are given by the fluctuation-dissipation theorem. We derive coupled-Mode equations for the Lasing-Mode amplitudes and obtain a formula for the linewidths in terms of simple integrals over the steady-state Lasing Modes.
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steady state ab initio laser theory generalizations and analytic results
Physical Review A, 2010Co-Authors: Yidong Chong, Douglas A StoneAbstract:We improve the steady-state ab initio laser theory (SALT) of Tuereci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states that contains the exact threshold Lasing Mode. For cavities with nonuniform index and/or nonuniform gain, the new basis set allows the steady-state Lasing properties to be computed with much greater efficiency. This formulation of the SALT can be solved in the single-pole approximation, which gives the intensities and thresholds, including the effects of nonlinear hole-burning interactions to all orders, with negligible computational effort. The approximation yields a number of analytic predictions, including a 'gain-clamping' transition at which strong modal interactions suppress all higher Modes. We show that the single-pole approximation agrees well with exact SALT calculations, particularly for high-Q cavities. Within this range of validity, it provides an extraordinarily efficient technique for Modeling realistic and complex lasers.
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steady state ab initio laser theory generalizations and analytic results
Physical Review A, 2010Co-Authors: Yidong Chong, Douglas A StoneAbstract:We improve the steady-state ab initio laser theory (SALT) of T\"ureci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states that contains the exact threshold Lasing Mode. For cavities with nonuniform index and/or nonuniform gain, the new basis set allows the steady-state Lasing properties to be computed with much greater efficiency. This formulation of the SALT can be solved in the single-pole approximation, which gives the intensities and thresholds, including the effects of nonlinear hole-burning interactions to all orders, with negligible computational effort. The approximation yields a number of analytic predictions, including a ``gain-clamping'' transition at which strong modal interactions suppress all higher Modes. We show that the single-pole approximation agrees well with exact SALT calculations, particularly for high-$Q$ cavities. Within this range of validity, it provides an extraordinarily efficient technique for Modeling realistic and complex lasers.
L J Wang - One of the best experts on this subject based on the ideXlab platform.
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whispering gallery Mode resonator stabilized narrow linewidth fiber loop laser
arXiv: Optics, 2012Co-Authors: B Sprenger, Harald G L Schwefel, L J WangAbstract:We demonstrate a narrow line, fiber loop laser using Erbium-doped fiber as the gain material, stabilized by using a microsphere as a transmissive frequency selective element. Stable Lasing with a linewidth of 170 kHz is observed, limited by the experimental spectral resolution. A linear increase in output power and a red-shift of the Lasing Mode were also observed with increasing pump power. Its potential application is also discussed.
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whispering gallery Mode resonator stabilized narrow linewidth fiber loop laser
Optics Letters, 2009Co-Authors: B Sprenger, Harald G L Schwefel, L J WangAbstract:We demonstrate a narrow-line fiber loop laser using erbium-doped fiber as the gain material, stabilized by using a microsphere as a transmissive frequency selective element. Stable Lasing with a linewidth of 170 kHz is observed, limited by the experimental spectral resolution. A linear increase in output power and a redshift of the Lasing Mode were also observed with increasing pump power. Its potential applications are discussed.
Hendry Izaac Elim - One of the best experts on this subject based on the ideXlab platform.
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gain narrowing and random Lasing from dye doped polymer dispersed liquid crystals with nanoscale liquid crystal droplets
Applied Physics Letters, 2006Co-Authors: Yan Ju Liu, Hendry Izaac ElimAbstract:Dye-doped polymer-dispersed liquid crystals have been studied for random Lasing. The dye-doped polymer-dispersed liquid crystal film was fabricated by photoinitiated polymerization with a collimated 514.5nm Ar+ laser beam. Scanning electron microscopy analysis showed that most liquid crystal droplets in polymer matrix ranged from 20to80nm. Gain narrowing and random Lasing from dye-doped polymer dispersed liquid crystals were observed under the excitation of a frequency-doubled Nd:YAG (yttrium aluminum garnet) laser operating at a wavelength of 532nm. The possible mechanism was proposed to explain the random Lasing. The threshold of the random Lasing was about 25μJ/pulse. The linewidth of the Lasing peaks was about 1nm. With the film thickness of 6.5μm, the Lasing Mode was nearly transverse electric polarized.Dye-doped polymer-dispersed liquid crystals have been studied for random Lasing. The dye-doped polymer-dispersed liquid crystal film was fabricated by photoinitiated polymerization with a collimated 514.5nm Ar+ laser beam. Scanning electron microscopy analysis showed that most liquid crystal droplets in polymer matrix ranged from 20to80nm. Gain narrowing and random Lasing from dye-doped polymer dispersed liquid crystals were observed under the excitation of a frequency-doubled Nd:YAG (yttrium aluminum garnet) laser operating at a wavelength of 532nm. The possible mechanism was proposed to explain the random Lasing. The threshold of the random Lasing was about 25μJ/pulse. The linewidth of the Lasing peaks was about 1nm. With the film thickness of 6.5μm, the Lasing Mode was nearly transverse electric polarized.
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gain narrowing and random Lasing from dye doped polymer dispersed liquid crystals with nanoscale liquid crystal droplets
Applied Physics Letters, 2006Co-Authors: Yan Jun Liu, Xiao Wei Sun, Hendry Izaac ElimAbstract:Dye-doped polymer-dispersed liquid crystals have been studied for random Lasing. The dye-doped polymer-dispersed liquid crystal film was fabricated by photoinitiated polymerization with a collimated 514.5nm Ar+ laser beam. Scanning electron microscopy analysis showed that most liquid crystal droplets in polymer matrix ranged from 20to80nm. Gain narrowing and random Lasing from dye-doped polymer dispersed liquid crystals were observed under the excitation of a frequency-doubled Nd:YAG (yttrium aluminum garnet) laser operating at a wavelength of 532nm. The possible mechanism was proposed to explain the random Lasing. The threshold of the random Lasing was about 25μJ/pulse. The linewidth of the Lasing peaks was about 1nm. With the film thickness of 6.5μm, the Lasing Mode was nearly transverse electric polarized.
