Double injection resonator

集成微波光电子学利用光电子集成技术实现多功能和高性能的单片集成微波光电子系统，在手机、无线和星际通信、以及电视、分布式天线系统、光学信号处理和医学成像等领域凸显出巨大的应用潜力。文中，董俊教授回顾了硅基光电子学在集成微波光电子学和大规模集成光学子学领域的重要性，评述了硅基光电子学研究的最新进展和存在问题，并对该方向今后发展进行了展望。 该文作者董俊，教授、博导，电子科学与技术学院（国家示范性微电子学院）副院长，研究方向为固体激光技术、光学材料、激光模式特性研究、光学旋涡。【Abstract】A single silicon double injection resonator provides flexible response shapes, large free spectral range and tolerance to temperature deviations and fabrication defects, paving the way for high-performance integrated photonics

美国州际高速公路铺设与种族冲突——以40号州际高速公路为例

州际高速公路的铺设是美国交通史上破天荒的举措,其重要性和巨大影响毋庸置疑,但也产生了新的种族问题:大量非洲裔美国人社区在高速公路的修建过程中遭到了刻意破坏,加重了种族矛盾。其...中国国家留学基金“国家建设高水平大学公派研究生项目”(201606310146)资

Observation of repetitively nanosecond pulse-width transverse patterns in microchip self-Q-switched laser

Repetitively nanosecond pulse-width transverse pattern formation in a plane-parallel microchip Cr,Nd: yttrium-aluminum-garnet (YAG) self-Q-switched laser was investigated. The complex point-symmetric transverse patterns were observed by varying the pump beam diameter incident on the Cr,Nd:YAG crystal. The gain guiding effect and the thermal effect induced by the pump power in microchip Cr,Nd:YAG laser control the oscillating transverse modes. These transverse pattern formations were due to the variation of the saturated inversion population and the thermal induced index profile along radial and longitudinal direction in the Cr,Nd:YAG crystal induced by the pump power incident on the Cr,Nd:YAG crystal. These were intrinsic properties of such a microchip self-Q-switched laser. The longitudinal distribution of the saturated inversion population inside the gain medium plays an important role on the transverse pattern formation. Different sets of the transverse patterns corresponds to the different saturated inversion population distribution inside microchip Cr,Nd:YAG crystal

Advances in Ince-Gaussian Modes Laser

Ince-Gaussian模式是继Hermite-Gaussian和Laguerre-Gaussian模式之后的第3类近轴波动方程的完整解系,其横模图形多样,且螺旋Ince-Gaussian模式存在分离的涡旋结构并携带轨道角动量,这些特点使其在微粒操控、生物医学、光学通信等领域有广阔的应用前景,因而受到广泛的关注。基于此,阐述了Ince-Gaussian模式的理论基础,详细介绍了其产生的方法及相应的优缺点,指出今后实现高效Ince-Gaussian模式激光输出的研究方向。Ince-Gaussian modes are the third complete family of exact and orthogonal solutions of the paraxial wave equation following the Hermite-Gaussian and Laguerre-Gaussian modes. Its transverse mode pattern is diversiform,and the helical Ince-Gaussian modes exist separate spiral vortex structures and carry orbital angular momentum,which makes Ince-Gaussian modes have broad prospects in the fields of particle manipulation, biomedical, optical communications and so on, and have attracted a great deal of interests. The theory of Ince- Gaussian beam is presented in the paper, the methods of generation of Ince- Gaussian mode laser are addressed, and the future development of high efficient Ince-Gaussian mode laser is disscussed.国家自然科学基金(61475130;61275143);; 厦门大学基础创新科研基金(201312G008

「無乃」（毋乃）語法解

[[issue]]26

談「相」字的詞性演變

[[issue]]23

Progress in Laser Ignition Based on Passively Q-Switched Solid-State Lasers

稀薄燃烧是一种先进的燃烧方法,采用稀薄燃烧技术可以使发动机在减少废气排放的同时提高热效率。稀薄燃烧催发了激光点火技术的应用。最近几十年,脉冲宽度短、峰值功率高的被动调Q固体激光器得到了飞速的发展,特别是采用掺钕离子(nd3+)和镱离子(yb3+)的激光材料作为激光增益介质,用Cr4+∶yAg作为被动调Q开关的微片固体激光器在激光点火研究方面取得了长足的进展。系统地介绍了激光点火的机理和应用于激光点火的基于nd∶yAg/Cr4+∶yAg与yb∶yAg/Cr4+∶yAg的被动调Q固体激光器的最新研究进展,以及两类被动调Q激光器在激光点火应用中的优缺点,并指出了yb∶yAg/Cr4+∶yAg被动调Q微片激光器在激光点火应用中的优势、需解决的问题及发展方向。Laser ignition technology emerges as an advanced combustion method for engine.It can make the engine reduce waste gas emission and improve the thermal effect.Lean burning improves thermal efficiency and reduces exhaust emissions by laser ignition.In recent decades, short pulse, high peak power passively Q-switched solid-state lasers are developed rapidly for their potential applications in laser ignition.Especially the passively Q-switched lasers using neodymium ion(Nd3+) or ytterbium ion(Yb3+) doped materials as the laser gain media and Cr4+∶YAG as the saturable absorber, make much progress in potential laser ignition applications.We overviewe the mechanism of laser ignition and progresses in passively Q-switched solid-state lasers based on Nd∶YAG/Cr4+∶YAG and Yb∶YAG/Cr4+∶YAG.And the advantages and disadvantages of these two types passively Q-switched lasers used in laser ignition are discussed systematically.The advantages of Yb∶YAG/Cr4+∶YAG passively Q-switched microchip lasers used in laser ignition are addressed for future application in engine ignition.And the key issues for developing high peak power Yb∶YAG/Cr4+∶YAG passively Q-switched microchip lasers are also addressed.国家自然科学基金(61275143); 教育部新世纪优秀人才支持计划(NCET-09-0669

Advances in Passively Q-Switched Yb--(3+)-Doped Laser Materials Microchip Solid-State Lasers

激光二极管抽运的被动调Q固体激光器不仅结构简单、紧凑,而且由于采用端面抽运的方式有效地耦合了抽运光和激光可以获得高光束质量的激光输出,同时由于其独特的短腔长从而可以实现亚纳秒、高峰值功率的激光输出,在激光加工、激光通信、医疗、生物和材料微结构分析等方面有非常广阔的应用前景。在过去的十多年里,采用掺镱离子(yb3+)的激光材料作为激光增益介质,用Cr4+∶yAg和半导体可饱和吸收镜等作为被动调Q开关的被动调Q微片激光器取得了长足的进展,不仅获得与基于掺钕离子激光材料作为增益介质所实现的相同的高峰值功率被动调Q激光输出,而且在激光效率及激光设计的灵活性方面凸显出了明显的优点。系统地介绍了基于掺yb3+离子激光材料作为激光增益介质实现被动调Q微片激光器的研究进展及其在未来的发展趋势。Laser-diode pumped passively Q-switched solid-state lasers,with compact configuration,excellent beam quality owing to good match-up of pump and laser light,easy to achieve sub-nanosecond pulse width and high peak power,have widely applications in laser processing,telecommunications,surgery,biology,material microstructure analysis and so on.In the past decade,dramatic progresses have been made in passively Q-switched solid-state lasers based on ytterbium doped laser material and saturable absorber such as Cr4+∶YAG,semiconductor saturable absorber mirror(SESAM).Passively Q-switched Yb3+ doped solid-state lasers have achieved not only the same high peak power output,but also with better efficiency and flexible designs.The progresses and future work on passively Q-switched Yb3+ doped laser materials microchip lasers have been overviewed.教育部新世纪优秀人才支持计划(NCET-09-0669)资助课

Continuous-wave and Q-switched microchip laser performance of Yb : Y3Sc2Al3O12 crystals

Optical properties of Yb:Y3Sc2Al3O12 crystal were investigated and compared with those from Yb:YAG crystals. The broad absorption and emission spectra of Yb:Y3Sc2Al3O12 show that this crystal is very suitable for laser-diode pumping and ultrafast laser pulse generation. Laser-diode pumped continuous-wave and passively Q-switched Yb:Y3Sc2Al3O12 lasers with Cr4+: YAG crystals as saturable absorber have been demonstrated for the first time. Continuous-wave output power of 1.12 W around 1032 nm ( multi-longitudinal modes) was measured with an optical-to-optical efficiency of 30%. Laser pulses with pulse energy of over 31 mu J and pulse width of 2.5 ns were measured at repetition rate of over 12.7 kHz; a corresponding peak power of over 12 kW was obtained. The longitudinal mode selection by a thin plate of Cr4+: YAG as an intracavity etalon was also observed in passively Q-switched Yb:Y3Sc2Al2O12 microchip lasers. (C) 2008 Optical Society of America

Laser performance of monolithic Cr,Nd : YAG self-Q-switched laser

The self-Q-switched laser performance of monolithic Cr4+.,Nd3+:YAG concave-planar resonator with 5-mm length was studied experimentally and theoretically. The slope efficiency is as high as 24% and pump threshold is as low as 64 mW. The pulse width, the single pulse energy and the pulse repetition rate of monolithic Cr,Nd:YAG self-Q-switched laser were measured as a function of absorbed pump power. With the increase of pump power, the pulse width decreases and the pulse energy and the pulse repetition rate increase. The average output power of 91 mW with pulse width of 7 ns at repletion rate of 35.5 kHz was obtained at the maximum absorbed pump power of 440 mW, the peak power is as high as 370 W. The theoretical prediction of pulse energy, pulse width and pulse repetition rate as a function of absorbed pump power based on rate equations is in a good agreement with our experimental data. This can lead to develop the diode laser-pumped monolithic self-Q-switched solid-state microchip lasers. (C) 2003 Elsevier Science B.V. All rights reserved