201
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Kang I, Chandrasekhar S, Buhl L, Bernasconi PG, Liu X, Giles CR, Kazmierski C, Dupuis N, Decobert J, Alexandre F, Jany C, Garreau A, Landreau J, Rasras M, Cappuzzo M, Gomez LT, Chen YF, Earnshaw MP, Lee J, Leven A, Dorrer C. A hybrid electroabsorption modulator device for generation of high spectral-efficiency optical modulation formats. OPTICS EXPRESS 2008; 16:8480-8486. [PMID: 18545562 DOI: 10.1364/oe.16.008480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report a novel hybrid integrated optic device consisting of AlGaInAs/InP electroabsorption modulators and a four-arm silica-on-silicon planar lightwave circuit optical interferometer. The device is designed for generation of high spectral efficiency optical modulation formats. We demonstrate generation of 21.4 Gb/s quadrature phase shift keyed optical signals with electrical data drives of 2V(pp) amplitudes, achieving a bit error rate of 10(-9) with the required optical signal to noise ratio of ~18 dB in a 0.1 nm resolution bandwidth.
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202
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Chang YT, Huang YP, Su KW, Chen YF. Diode-pumped multi-frequency Q-switched laser with intracavity cascade Raman emission. OPTICS EXPRESS 2008; 16:8286-8291. [PMID: 18545541 DOI: 10.1364/oe.16.008286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A diode-pumped actively Q-switched mixed Nd:Y(0.3)Gd(0.7)VO(4) laser with an intracavity KTP crystal is developed to produce cascade SRS emission up to the fourth order. With an incident pump power of 14 W and a repetition rate of 50 kHz, the average output powers at the first, second, third and fourth Stokes modes are approximately 0.05 W, 0.61 W, 0.25 W, and 0.11 W, respectively. The maximum peak power is greater than 2 kW.
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203
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Huang JY, Liang HC, Su KW, Chen YF. Analytical model for optimizing the parameters of an external passive Q-switch in a fiber laser. APPLIED OPTICS 2008; 47:2297-2302. [PMID: 18449294 DOI: 10.1364/ao.47.002297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An analytical model is developed for optimizing two key parameters of an external passive Q-switch in a fiber laser from the criterion of the minimum average mode area inside the saturable absorber. One parameter is the optimum focal position that is analytically derived to be a function of the thickness and initial transmission of the saturable absorber. The other parameter is the optimum magnification of the reimaging optics that is analytically derived to be in terms of the numerical aperture and core radius of the laser fiber as well as the thickness and initial transmission of the saturable absorber. To demonstrate the utilization of the present model, an experiment on the subject of the passively Q-switched fiber laser is performed and optimized.
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204
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Fu HK, Chen CW, Wang CH, Chen TT, Chen YF. Creating optical anisotropy of CdSe/ZnS quantum dots by coupling to surface plasmon polariton resonance of a metal grating. OPTICS EXPRESS 2008; 16:6361-6367. [PMID: 18545339 DOI: 10.1364/oe.16.006361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An efficient method that can be used to control the optical anisotropy of CdSe/ZnS quantum dots by coupling to the surface plasmon polariton resonance of a metal grating has been demonstrated. It is found that the unpolarized emission and Raman scattering signals arising from CdSe/ZnS quantum dots can be manipulated and exhibit a strong anisotropic behavior based upon our strategy. The optical anisotropy is interpreted in terms of the coupling between the directional surface plasmon of metal grating and the emitted light beam of quantum dots. Due to the importance of quantum dots in optoelectronic devices, our new approach should be useful for future application.
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205
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Huang JY, Huang SC, Chang HL, Su KW, Chen YF, Huang KF. Passive Q switching of Er-Yb fiber laser with semiconductor saturable absorber. OPTICS EXPRESS 2008; 16:3002-3007. [PMID: 18542386 DOI: 10.1364/oe.16.003002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A high-performance AlGaInAs quantum-well saturable absorber is developed for passively Q-switched Er-Yb double-clad fiber lasers at 1560 nm. With an incident pump power of 13.5 W, an average output power of 1.26 W with a pulse repetition rate of 12 kHz is obtained. The maximum peak power is greater than 500 W.
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206
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Chen CC, Su KW, Chen YF, Huang KF. Various high-order modes in vertical-cavity surface-emitting lasers with equilateral triangular lateral confinement. OPTICS LETTERS 2008; 33:509-511. [PMID: 18311308 DOI: 10.1364/ol.33.000509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Large-aperture vertical-cavity surface-emitting lasers with an equilateral triangular lateral confinement are fabricated to investigate the formation of high-order resonant modes. The experimental lasing patterns are composed of the superscar mode, honeycomb eigenstate, and chaotic mode. Experimental results confirm the theoretical predictions that tiny symmetry breaking can cause the high-order modes to reveal miscellaneous states of integrable and chaotic systems.
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207
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Chang HJ, Chen TT, Huang LL, Chen YF, Tsai JY, Wang TC, Kuo HC. Optically modulated internal strain in InGaN quantum dots grown on SiN(x) nano masks. OPTICS EXPRESS 2008; 16:920-926. [PMID: 18542166 DOI: 10.1364/oe.16.000920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on SiN(x) nano masks. The modulated internal strain can induce a number of intriguing effects, including the change of refractive index and the redshift of InGaN A(1)(LO) phonon. The underlying mechanism can be well accounted for in terms of the variation of internal strain through the converse piezoelectric effect arising from the screening of the internal electric field due to spatial separation of photoexcited electrons and holes. Our results point out a convenient way for the fine tuning of physical properties in nitride-based semiconductor nanostructures, which is very important for high quality optoelectronic devices.
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208
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Lin HY, Chou YY, Cheng CL, Chen YF. Giant enhancement of band edge emission based on ZnO/TiO(2) nanocomposites. OPTICS EXPRESS 2007; 15:13832-13837. [PMID: 19550653 DOI: 10.1364/oe.15.013832] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Enhancement of band edge emission of ZnO nanorods up to a factor of 120 times has been observed in the composite consisting of ZnO nanorods and TiO(2) nanoparticles, while the defect emission of ZnO nanorods is quenched to noise level. Through a detailed investigation, it is found that the large enhancement mainly arises from fluorescence resonance energy transfer between the band edge transition of ZnO nanorods and TiO(2) nanoparticles. Our finding opens up new possibilities for the creation of highly efficient solid state emitters.
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209
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Chen LM, Hou R, Zhang ZH, Wang JS, An XR, Chen YF, Zheng HP, Xia GL, Zhang MJ. Electroejaculation and semen characteristics of Asiatic Black bears (Ursus thibetanus). Anim Reprod Sci 2007; 101:358-64. [PMID: 17250981 DOI: 10.1016/j.anireprosci.2006.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2006] [Revised: 12/03/2006] [Accepted: 12/05/2006] [Indexed: 11/18/2022]
Abstract
This study details the seminal traits in the rare Asiatic black bear, revealing that this species generally produces high quality, concentrated ejaculates containing sperm of high motility and morphological integrity and similar to other members of the Ursine lineage. Semen was collected by electroejaculation and 23 trials were performed on 18 bears. The mean values were obtained for volume (0.61 ml), pH (7.1), sperm concentration (1049 x 10(6) ml(-1)), total sperm counts (502.8 x 10(6)), motility percentage (63.8%), forward progressive status (3.5), abnormal sperm percentage (37.9%) and intact acrosome percentage (76.6%).
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210
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Huang YP, Liang HC, Huang JY, Su KW, Li A, Chen YF, Huang KF. Semiconductor quantum-well saturable absorbers for efficient passive Q switching of a diode-pumped 946 nm Nd:YAG laser. APPLIED OPTICS 2007; 46:6273-6. [PMID: 17805361 DOI: 10.1364/ao.46.006273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
InGaAs quantum wells and a Bragg mirror structure are grown on a GaAs substrate to simultaneously serve as a low-loss saturable absorber and an output coupler for highly efficient Q switching of a diode-pumped Nd:YAG laser operating at 946 nm. With an incident pump power of 9.2 W, the laser produces pulses of 38 ns duration with average pulse energy of as much as 20 microJ at a pulse repetition rate of 55 kHz.
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211
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Shih PC, Lee HH, Lai SC, Chen KM, Jiang ST, Chen YF, Shiow SJ. Efficacy of curcumin therapy against Angiostrongylus cantonensis-induced eosinophilic meningitis. J Helminthol 2007; 81:1-5. [PMID: 17381860 DOI: 10.1017/s0022149x07182353] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Angiostrongylus cantonensis can invade the central nervous system, leading to human eosinophilic meningitis or eosinophilic meningoencephalitis. Curcumin is a natural product which has the effects of anti-inflammation, anti-oxidation and anti-carcinogensis, while the administration of curcumin has been reported to possibly relieve the symptoms of meningitis. The present study tested the potential efficacy of curcumin in A. cantonensis-induced eosinophilic meningitis of BALB/c mice. Assay indicators for the therapeutic effect included the larvicidal effect, eosinophil counts and matrix metalloproteinase-9 (MMP-9) activity in angiostrongyliasis. Eosinophils were mildly reduced in treatment groups compared with infected-untreated mice. However, there were no significant differences in larvicidal effects or MMP-9 activity. This study suggests that anti-inflammatory treatment with curcumin alone has low efficacy, but the treatment does not interfere with MMP-9 expression and is not useful for larvicidal effects. The possible reasons include low curcumin across the blood-brain barrier and also those larvae that survive stimulate MMP-9 production, which promotes blood-brain barrier damage, with leukocytes then crossing the blood-brain barrier to cause meningitis. Further studies will be required to test these possibilities.
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212
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Chen CC, Su KW, Lu TH, Liu CC, Chen YF, Huang KF. Generation of two-dimensional chaotic vector fields from a surface-emitting semiconductor laser: analysis of vector singularities. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:026219. [PMID: 17930133 DOI: 10.1103/physreve.76.026219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 06/28/2007] [Indexed: 05/25/2023]
Abstract
We demonstrate experimental generation of two-dimensional (2D) chaotic vector fields from a surface-emitting microcavity laser with precisely control of the operating temperature and the operating current. The 2D optical vector field is found to be formed by frequency locking of two linearly polarized laser modes with different chaotic spatial structures. The eigenfunction expansion method is used to reconstruct the experimental wave function for analyzing the properties of the vector singularities. It is shown that the distribution of vector singularities obeys the sign rule of nearest-neighbor singularities in the phase space of the vector field.
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213
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Chang HJ, Hsieh YP, Chen TT, Chen YF, Liang CT, Lin TY, Tseng SC, Chen LC. Strong luminescence from strain relaxed InGaN/GaN nanotips for highly efficient light emitters. OPTICS EXPRESS 2007; 15:9357-65. [PMID: 19547278 DOI: 10.1364/oe.15.009357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Semiconductor heterostructures represent the most important building block for current optoelectronic devices. One of the common features of semiconductor heterostructures is the existence of internal strain due to lattice mismatch. The internal strain can tilt the band alignment and significantly alter the physical properties of semiconductor heterostructures, such as reducing the internal quantum efficiency of a light emitter. Here, we provide a convenient route to release the internal strain by patterning semiconductor heterostructures into nanotip arrays. The fabrication of the nanotip arrays was achieved by self-masked dry etching technique, which is simple, low cost and compatible with current semiconductor technologies. By implementing our approach to InGaN/GaN multiple quantum wells, we demonstrate that the light emission can be enhanced by up to 10 times. Our approach renders an excellent opportunity to manipulate the internal strain, and is very useful to create highly efficient solid state emitters.
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214
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Chen YF, Su KW, Chang YT, Yen WC. Compact efficient eye-safe intracavity optical parametric oscillator with a shared cavity configuration. APPLIED OPTICS 2007; 46:3597-601. [PMID: 17514321 DOI: 10.1364/ao.46.003597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We present a compact efficient eye-safe intracavity optical parametric oscillator pumped by a passively Q-switched Nd:YAG laser in a shared cavity configuration. A signal pulse of 3.3 mJ energy at a 1573 nm wavelength with a peak power of 150 kW was achieved. The effective conversion efficiency with respective to the optimized 1064 nm Q-switched pulse energy was as high as 51%.
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215
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Huang SC, Liu SC, Li A, Su KW, Chen YF, Huang KF. AlGaInAs quantum-well as a saturable absorber in a diode-pumped passively Q-switched solid-state laser. OPTICS LETTERS 2007; 32:1480-2. [PMID: 17546161 DOI: 10.1364/ol.32.001480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We demonstrate what is believed to be the first use of AlGaInAs quantum wells (QWs) as a saturable absorber in the Q switching of a high-power diode-pumped Nd-doped 1.06 mum laser. The barrier layers are designed to locate the QW groups in the region of the nodes of the lasing standing wave to avoid damage. With an incident pump power of 13.5 W, an average output power of 3.5 W with a Q-switched pulse width of 0.9 ns at a pulse repetition rate of 110 kHz was obtained.
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216
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Liang HC, Huang JY, Su KW, Lai HC, Chen YF, Huang KF, Zhang HJ, Wang JY, Jiang MH. Passively Q-switched Yb3+:YCa4O(BO3)3 laser with InGaAs quantum wells as saturable absorbers. APPLIED OPTICS 2007; 46:2292-6. [PMID: 17415399 DOI: 10.1364/ao.46.002292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A diode-pumped Yb:YCOB laser at 1086 nm is passively Q switched by using InGaAs quantum wells as saturable absorbers and utilizing the Bragg mirror structure as an output coupler. With an absorbed pump power of 9.2 W the laser produces pulses of 100 ms duration with average pulse energy of as much as 165 microJ at a pulse repetition rate of 7 kHz.
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217
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Chen CC, Liu CC, Su KW, Lu TH, Chen YF, Huang KF. Statistical properties of experimental coherent waves in microcavity lasers: analogous study of quantum billiard wave functions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:046202. [PMID: 17500973 DOI: 10.1103/physreve.75.046202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 01/10/2007] [Indexed: 05/15/2023]
Abstract
We use a microcavity laser to explore the properties of experimental coherent waves as an analogous study of the chaotic wave functions in quantum billiards. With the eigenstate expansion method, the experimental high-order chaotic coherent waves are well reconstructed. The reconstructed wave functions are employed to calculate the field and intensity correlations. It is found that the spreading of k-space (momentum space) distribution leads to not only wave localization in coordinate space but also enhancement of long-range correlations.
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218
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Chang HJ, Chen TW, Chen JW, Hong WC, Tsai WC, Chen YF, Guo GY. Current and strain-induced spin polarization in InGaN/GaN superlattices. PHYSICAL REVIEW LETTERS 2007; 98:136403. [PMID: 17501224 DOI: 10.1103/physrevlett.98.136403] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Indexed: 05/15/2023]
Abstract
The lateral current-induced spin polarization in InGaN/GaN superlattices (SLs) without an applied magnetic field is reported. The fact that the sign of the nonequilibrium spin changes as the current reverses and is opposite for the two edges provides a clear signature for the spin Hall effect. In addition, it is discovered that the spin Hall effect can be strongly manipulated by the internal strains. A theoretical work has also been developed to understand the observed strain-induced spin polarization. Our result paves an alternative way for the generation of spin polarized current.
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219
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Lu TH, Chen YF, Huang KF. Generation of polarization-entangled optical coherent waves and manifestation of vector singularity patterns. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:026614. [PMID: 17358443 DOI: 10.1103/physreve.75.026614] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Indexed: 05/14/2023]
Abstract
We use a high-level isotropic laser with off-axis focused and on-axis circular pumping to generate the high order polarization-entangled transverse modes. The main finding is that the complex transverse modes can be categorized into four types: square pattern, hyperbolic pattern, elliptic pattern, and circular pattern. Importantly, all types of the polarization-entangled modes can be well analyzed with the generalized coherent states. With the connection between theoretical analysis and experimental results, the formation of complex singularities can be clearly represented.
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220
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Chen YF, Lu TH, Huang KF. Hyperboloid structures formed by polarization singularities in coherent vector fields with longitudinal-transverse coupling. PHYSICAL REVIEW LETTERS 2006; 97:233903. [PMID: 17280204 DOI: 10.1103/physrevlett.97.233903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Indexed: 05/13/2023]
Abstract
The propagation-dependent polarization vector fields are experimentally created from an isotropic microchip laser with a longitudinal-transverse coupling and entanglement of the polarization states. The experimental three-dimensional coherent vector fields are analytically reconstructed with a coherent superposition of orthogonal circularly polarized vortex modes. Each polarized component is found to comprise two Laguerre-Gaussian modes with different topological charges. With the analytical representation, the polarization singularities, on which the electric polarization ellipse is purely circular (C lines) or purely linear (L surfaces), are explored. The C line singularities are found to form an intriguing hyperboloidal structure.
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221
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Liu CC, Lu TH, Chen YF, Huang KF. Wave functions with localizations on classical periodic orbits in weakly perturbed quantum billiards. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:046214. [PMID: 17155160 DOI: 10.1103/physreve.74.046214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Indexed: 05/12/2023]
Abstract
We analytically investigate quantum wave functions with localizations on classical periodic orbits (POs) in the circular billiards. We construct the coherent states which are the coherent superpositions of nearly degenerate eigenstates and found to be localized around single classical POs. With the constructed coherent states, we can analytically express the mesoscopic eigenstates in the weakly perturbed systems, which are found to be localized on the ensemble of classical POs. Furthermore, these coherent states can be utilized to study the quantum vortex structures in quantum billiards.
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222
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Wang FB, Li J, Wang P, Zhu XH, Zhang MJ, Peng ZH, Li SL, Yong LP, Chen YF, Sun XS, Zheng DN. Effect of oxygen content on the transport properties of LaTiO(3+β/2) thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2006; 18:5835-5847. [PMID: 21690800 DOI: 10.1088/0953-8984/18/26/004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The structural and transport properties of LaTiO(3+β/2) epitaxial thin films, grown at different oxygen pressures ranging from 6.6 × 10(-4) to 5 Pa, have been investigated. X-ray diffraction peaks of the films shift to lower angles with increasing oxygen pressure, indicative of a variation of the corresponding lattice spacing. All the films show T(2) dependence of resistivity over a large temperature range of ∼200 K, suggesting a band-filling-induced metallic Fermi-liquid behaviour. Upturns in resistivity have been revealed at low temperatures, which could be ascribed to the Anderson-localization effect caused by the cation vacancies. Furthermore, for the thin films grown at high oxygen pressures of 0.5 and 5 Pa, the dependence of resistivity on temperature shows a maximum at high temperatures. The maximum seems to support the argument that transition between t-orbital ordering and disordering plays an important role in dominating transport properties at high temperatures. Carrier density deduced from Hall coefficient increases with the decrease of oxygen content, and shows strong temperature dependence. From the experimental data, it can be asserted that in the LaTiO(3+β/2) thin films, besides the band filling effect, localization or disorder caused by La and Ti vacancy effects controls the unique transport properties.
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223
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Su KW, Huang SC, Li A, Liu SC, Chen YF, Huang KF. High-peak-power AlGaInAs quantum-well 1.3-mum laser pumped by a diode-pumped actively Q-switched solid-state laser. OPTICS LETTERS 2006; 31:2009-11. [PMID: 16770415 DOI: 10.1364/ol.31.002009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report a room-temperature high-peak-power AlGaInAs 1.36 microm TEM00 laser pumped by a diode-pumped actively Q-switched Nd:YAG 1.06 microm laser. With an average pump power of 1.0 W, an average output power of 140 mW was obtained at a pulse repetition rate of 10 kHz. With a peak pump power of 8.3 kW, the highest peak output power was 1.5 kW at a pulse repetition rate of 5 kHz.
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224
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Lin YY, Chen SY, Chiang AC, Tu RY, Huang YC, Chen YF, Chen YH. Single-longitudinal-mode, tunable dual-wavelength,CW Nd:YVO(4) laser. OPTICS EXPRESS 2006; 14:5329-5334. [PMID: 19516699 DOI: 10.1364/oe.14.005329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a single-longitudinal-mode CW diode-pumped Nd:YVO(4) laser emitting at both 1064 and 1342 nm with 10% optical efficiency at 20-W pump power. The measured spectral widths at 1064 and 1342 nm were less than 450 MHz and 400 MHz, respectively. The two emission wavelengths can be independently tuned over the lasing bandwidths of the dual-wavelength laser.
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225
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Chen YF, Lu TH, Su KW, Huang KF. Devil's staircase in three-dimensional coherent waves localized on Lissajous parametric surfaces. PHYSICAL REVIEW LETTERS 2006; 96:213902. [PMID: 16803236 DOI: 10.1103/physrevlett.96.213902] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Indexed: 05/09/2023]
Abstract
We experimentally demonstrate the significance of the longitudinal-transverse coupling in the mesoscopic regime by using a high-Q laser resonator as an analog experiment. The longitudinal-transverse coupling is found to lead to the three-dimensional (3D) coherent waves that are localized on the parametric surfaces with Lissajous transverse patterns. More strikingly, experimental results reveal that the mode locking of the 3D coherent states forms a nearly complete Devil's staircase with the hierarchical ordering.
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226
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Lin HY, Cheng CL, Chou YY, Huang LL, Chen YF, Tsen KT. Enhancement of band gap emission stimulated by defect loss. OPTICS EXPRESS 2006; 14:2372-9. [PMID: 19503575 DOI: 10.1364/oe.14.002372] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Defect radiation has been always considered as the most important loss for an emitter based on band gap emission. Here, we propose a novel approach which goes against this conventional wisdom. Based on the resonance effect between the surface plasmon of metal nanoparticles and defect emission, it is possible to convert the useless defect radiation to the useful excitonic emission with a giant enhancement factor. Through the transfer of the energetic electrons excited by surface plasmon from metal nanoparticles to the conduction band of the emitter, the band gap emission can be greatly enhanced, while the defect emission can be suppressed to noise level.
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227
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Chen YF, Lu TH, Huang KF. Observation of spatially coherent polarization vector fields and visualization of vector singularities. PHYSICAL REVIEW LETTERS 2006; 96:033901. [PMID: 16486699 DOI: 10.1103/physrevlett.96.033901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Indexed: 05/06/2023]
Abstract
We present experimental observations of polarization vector fields from a highly isotropic microchip laser with a large Fresnel number. The experimental polarization vector field leads to complex entanglement of spatial structures and polarization states. We theoretically derive the representation of generalized coherent states to reconstruct the experimental polarization-resolved patterns. The analytical and precise reconstruction enables the vector singularities to be clearly visualized.
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228
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Chen YF, Su KW, Lu TH, Huang KF. Manifestation of weak localization and long-range correlation in disordered wave functions from conical second harmonic generation. PHYSICAL REVIEW LETTERS 2006; 96:033905. [PMID: 16486703 DOI: 10.1103/physrevlett.96.033905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Indexed: 05/06/2023]
Abstract
We experimentally demonstrate that the near-field patterns of conical second harmonic generation of a laser in random domain structures can be used to explore the spatial structure of two-dimensional disordered wave functions with weak localization. The statistics of the experimental near-field patterns agree very well with the theoretical distributions. In addition to the short-range correlation, the localization effects are found to contribute a nearly constant value to the long-range correlation. The result of this Letter also confirms the possibility of using conical second harmonic generation as a diagnostic tool for topographical characterization of crystals.
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229
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Chen YF, Su KW, Zhang HJ, Wang JY, Jiang MH. Efficient diode-pumped actively Q-switched Nd:YAG/BaWO4 intracavity Raman laser. OPTICS LETTERS 2005; 30:3335-7. [PMID: 16389823 DOI: 10.1364/ol.30.003335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Barium tungstate (BaWO4) is employed to achieve efficient stimulated Raman scattering conversion in a compact diode-pumped actively Q-switched Nd:YAG laser. With an incident pump power of 9.2 W, 1.56 W of 1181 nm first-Stokes average output power was generated at a pulse repetition rate of 20 kHz, corresponding to an optical-to-optical conversion efficiency of 16.9%.
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Tsai L, Chen YF, Lin S, Lin Y, Huang Y. Compact efficient passively Q-switched Nd:GdVO4/PPLN/Cr4+:YAG tunable intracavity optical parametric oscillator. OPTICS EXPRESS 2005; 13:9543-9547. [PMID: 19503157 DOI: 10.1364/opex.13.009543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on a compact efficient diode pumped passively Q-switched Nd:GdVO4/Cr4+:YAG/PPLN intracavity optical parametric oscillator (OPO) with a shared-resonator configuration. Experimental results reveal that the amplitude stability of the shared-resonator configuration is substantially superior to that of the conventional coupledresonator configuration. At a diode pump power of 15 W, the compact intracavity OPO cavity produces the average power greater than 900 mW with a pulse repetition rate of 36 kHz. The output pulses noticeably display the mode-locking phenomenon that leads to the maximum peak power to be higher than 20 kW.
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231
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Gao B, Chen YF, Fuhrer MS, Glattli DC, Bachtold A. Four-point resistance of individual single-wall carbon nanotubes. PHYSICAL REVIEW LETTERS 2005; 95:196802. [PMID: 16384008 DOI: 10.1103/physrevlett.95.196802] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Indexed: 05/05/2023]
Abstract
We have studied the resistance of single-wall carbon nanotubes measured in a four-point configuration with noninvasive voltage electrodes. The voltage drop is detected using multiwalled carbon nanotubes while the current is injected through nanofabricated Au electrodes. The resistance at room temperature is shown to be linear with the length as expected for a classical resistor. This changes at cryogenic temperature; the four-point resistance then depends on the resistance at the Au-tube interfaces and can even become negative due to quantum-interference effects.
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Chen YF, Lu TH, Su KW, Huang KF. Quantum signatures of nonlinear resonances in mesoscopic systems: efficient extension of localized wave functions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:056210. [PMID: 16383730 DOI: 10.1103/physreve.72.056210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 08/12/2005] [Indexed: 05/05/2023]
Abstract
We investigate the quantum signatures of classical nonlinear resonances by making the analytic connection between the quantum wave functions and the classical periodic orbits for the uncoupled systems. It is found that the highly efficient extension of the localized coherent states within the classical caustics is an intriguing phenomenon in mesoscopic systems with nonlinear resonances. With the theoretical analysis, we experimentally demonstrate that the laser resonator with an intracavity saturable absorber can be employed to visualize the wave patterns analogous to the quantum wave functions associated with Fermi resonance.
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233
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Chen YF, Ku ML, Su KW. High-power efficient tunable Nd:GdVO4 laser at 1083 nm. OPTICS LETTERS 2005; 30:2107-9. [PMID: 16127925 DOI: 10.1364/ol.30.002107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
An efficient tunable diode-pumped Nd:GdVO4 laser at 1083 nm has been constructed by suppressing the higher gain transition near 1063 nm. With 12.5 W diode pump power, the free-running output power centered about 1083 nm was up to 3.4 W, corresponding to an optical-to-optical conversion efficiency of 30.1%. When a simple uncoated etalon was used as a wavelength-selective element, the output power at each helium transition was higher than 2.5 W.
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234
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Su KW, Lai HC, Li A, Chen YF, Huang KF. InAs/GaAs quantum-dot saturable absorber for a diode-pumped passively mode-locked Nd:YVO4 laser at 1342 nm. OPTICS LETTERS 2005; 30:1482-4. [PMID: 16007781 DOI: 10.1364/ol.30.001482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report that InAs/GaAs quantum dots were developed to be saturable absorbers as well as output couplers in diode-pumped passively mode-locked Nd:YVO4 lasers at 1342 nm. With an incident pump power of 12.6 W, an average output power of 0.85 W with a mode-locked pulse width of 26 ps at a repetition rate of 152 MHz was obtained.
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Lai HC, Li A, Su KW, Ku ML, Chen YF, Huang KF. InAs/GaAs quantum-dot saturable absorbers for diode-pumped passively Q-switched Nd-doped 1.3-microm lasers. OPTICS LETTERS 2005; 30:480-482. [PMID: 15789709 DOI: 10.1364/ol.30.000480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A low-loss semiconductor saturable absorber based on InAs/GaAs quantum dots was developed for Q switching of a diode-pumped Nd-doped laser operating at 1.3 microm. With an InAs/GaAs quantum-dot saturable absorber, a diode-pumped Nd:YVO4 laser at 1342 nm was achieved. With an incident pump power of 2.2 W, an average output power of 360 mW with a Q-switched pulse width of 90 ns at a pulse repetition rate of 770 kHz was obtained.
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Chen YF. Stimulated Raman scattering in a potassium titanyl phosphate crystal: simultaneous self-sum frequency mixing and self-frequency doubling. OPTICS LETTERS 2005; 30:400-402. [PMID: 15762441 DOI: 10.1364/ol.30.000400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A potassium titanyl phosphate crystal is used to achieve efficient stimulated Raman scattering conversion with simultaneous self-sum frequency mixing and self-frequency doubling. Inside a diode-pumped Nd:YAG Q-switched laser cavity, 1.03 W of 1129-nm second Stokes average output power and 0.25 W of 548-nm sum-frequency average power are simultaneously generated with a diode input power of 10 W at a pulse repetition rate of 10 kHz.
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Hou J, Lei TH, Liu L, Cui XH, An XR, Chen YF. DNA methylation patterns in in vitro-fertilised goat zygotes. Reprod Fertil Dev 2005; 17:809-13. [PMID: 16476208 DOI: 10.1071/rd05075] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 09/25/2005] [Indexed: 11/23/2022] Open
Abstract
Recent studies have shown that zygote demethylation patterns in mammals are variable among species. However, the methylation patterns of goat zygotes have not yet been reported on. In the present study, using immunofluorescence staining with an antibody against 5-methylcytosine, the methylation patterns of in vitro-derived goat zygotes were studied. The results indicate that goat zygotes do not undergo active global demethylation during pronuclei development, which is similar to the situation in ovine, but not in murine or bovine zygotes. This is believed to be the first report regarding methylation in goat zygotes.
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Abstract
An efficient compact diode-pumped actively Q-switched Nd:GdVO4 laser at 1521 nm is demonstrated by use of the nonlinear optical process of stimulated Raman scattering. With a 13.6-W diode pump power, greater than 1.18 W of 1521-nm average power at a repetition rate of 20 kHz is generated. At a repetition rate of 5 kHz, the pulse width is shorter than 5 ns and the peak power is higher than 20 kW.
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Chen YF, Ku ML, Tsai LY, Chen YC. Diode-pumped passively Q-switched picosecond Nd:GDxY1-xVO4 self-stimulated raman laser. OPTICS LETTERS 2004; 29:2279-2281. [PMID: 15524380 DOI: 10.1364/ol.29.002279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An efficiency of 8.2% is demonstrated for a diode-pumped passively Q-switched self-stimulated Raman laser with an a-cut mixed vanadate crystal, Nd:Gd0.8Y0.2VO4. At 2.2 W of incident pump power, the self-stimulated Raman laser produces pulses as short as 660 ps at a Stokes wavelength of 1175 nm with 2.7 microJ of energy per pulse at a 66-kHz repetition rate.
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Chen YF. Compact efficient all-solid-state eye-safe laser with self-frequency Raman conversion in a Nd:YVO4 crystal. OPTICS LETTERS 2004; 29:2172-2174. [PMID: 15460892 DOI: 10.1364/ol.29.002172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An efficient compact eye-safe laser at 1525 nm is presented by use of self-frequency Raman conversion in a diode-pumped actively Q-switched Nd:YVO4 1342-nm laser. At an incident pump power of 13.5 W, the self-stimulated Raman laser produces 1.2 W of 1525-nm average output power at a repetition rate of 20 kHz. The corresponding peak power at 1525 nm is generally greater than 10 kW for repetition rates from 5 to 20 kHz.
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Chen YF. High-power diode-pumped actively Q-switched Nd:YVO4 self-Raman laser: influence of dopant concentration. OPTICS LETTERS 2004; 29:1915-1917. [PMID: 15357358 DOI: 10.1364/ol.29.001915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Efficient self-Raman frequency conversion from a diode-pumped actively Q-switched Nd:YVO4 laser at 1064 nm to Stokes emission at 1176 nm is achieved for the first time to the author's knowledge. With a 0.2-at.% Nd:YVO4 crystal, greater than 1.5 W of power at a wavelength of 1176 nm at a repetition rate of 20 kHz was generated with a diode pump power of 10.8 W, corresponding to a conversion of 13.9%. Pulse width and peak power were 18 ns and 4.2 kW, respectively.
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Chen YF, Wang RM, Zhang HZ, Sun XC, Zhang ZS, Xing YJ, Yu DP. TEM investigations on ZnO nanobelts synthesized via a vapor phase growth. Micron 2004; 35:481-7. [PMID: 15120134 DOI: 10.1016/j.micron.2004.02.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Unusual ZnO nanostructures have been successfully synthesized via selenium-controlled chemical vapor phase growth on Si (111) substrates at about 500 degrees C. The microstructure and chemical compositional characteristics of the ZnO nanomaterials have been systematically investigated by means of analytical transmission electron microscopy (TEM), including energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. Most of the nanostructures have a belt-like morphology with typical widths of approximately 150 nm and lengths up to several micrometers. All the investigated materials are found to be stoichiometric ZnO with a hexagonal crystal structure. The growth directions for the nanobelts are found to be [1010] and [2110] respectively. Regular-triangle and needle-like heads with diameters only approximately 25-35 nm have been found in the straight nanobelts. High-resolution TEM images indicate that all the nanostructures are single crystals and free of defects. The growth mechanisms of such interesting and unique morphologies are briefly discussed.
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Chen YF. Efficient subnanosecond diode-pumped passively Q-switched Nd:YVO4 self-stimulated Raman laser. OPTICS LETTERS 2004; 29:1251-1253. [PMID: 15209262 DOI: 10.1364/ol.29.001251] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Generation of efficient subnanosecond self-stimulated Raman pulses by a diode-pumped passively Q-switched Nd:YVO4/Cr4+:YAG laser is demonstrated. Experimental results reveal that self-frequency Raman conversion can be achieved with a c-cut Nd:YVO4 crystal in a nearly hemispherical cavity. At 2.0 W of incident pump power, the self-stimulated Raman laser produces stable 710-ps pulses at a Stokes wavelength of 1178.6 nm with 7.2 microJ of pulse energy at a 17-kHz repetition rate.
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Franco V, Feng JA, Perry G, Novak L, Fintel M, Chen YF, Oparil S. 118 IMPAIRED VENTRICULAR FUNCTION AND INCREASED CARDIAC COLLAGEN IN ATRIAL NATRIURETIC PEPTIDE-NULL MICE EXPOSED TO PRESSURE OVERLOAD. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Franco V, Feng JA, Perry G, Novak L, Fintel M, Chen YF, Oparil S. 278 IMPAIRED VENTRICULAR FUNCTION AND INCREASED CARDIAC COLLAGEN IN ATRIAL NATRIURETIC PEPTIDE-NULL MICE EXPOSED TO PRESSURE OVERLOAD. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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246
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Li P, Oparil S, Chen YF. 178 FIBROBLAST GROWTH FACTOR UPREGULATES PERIOSTIN AND OSTEOPONTIN EXPRESSION VIA DISTINCT SIGNALING PATHWAYS IN RAT PULMONARY ARTERIAL SMOOTH MUSCLE CELLS. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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247
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Sheridan AE, Feng JA, Wang D, Li P, Oparil S, Chen YF. 119 ATRIAL NATRIURETIC PEPTIDE MODULATES EXTRACELLULAR MATRIX EXPRESSION IN PATHOLOGIC BUT NOT PHYSIOLOGIC LEFT VENTRICULAR HYPERTROPHY. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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248
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Franco V, Feng JA, Perry G, Novak L, Fintel M, Chen YF, Oparil S. IMPAIRED VENTRICULAR FUNCTION AND INCREASED CARDIAC COLLAGEN IN ATRIAL NATRIURETIC PEPTIDE-NULL MICE EXPOSED TO PRESSURE OVERLOAD. J Investig Med 2004. [DOI: 10.1097/00042871-200401001-00671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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249
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Feng W, Miller AP, Xing D, Chen YF, Oparil S. 184 ESTROGEN ATTENUATES INFLAMMATORY MEDIATOR mRNA EXPRESSION IN BALLOON INJURED RAT CAROTID ARTERY. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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250
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Miller AP, Feng W, Fintel M, Smith M, Xing D, Chen YF, Oparil S. 301 ESTROGENIC VASOPROTECTION IS LOST IN AGED RATS. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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