Mode-locked quantum-dot lasers 锁模量子点激光器
半导体锁模激光器的英语
半导体锁模激光器的英语Semiconductor Mode-Locked Lasers.Semiconductor mode-locked lasers (MLLs) are a type of laser that emits pulses of light with extremely short durations, typically in the picosecond or femtosecond range. They are based on semiconductor materials, such as gallium arsenide (GaAs) or indium phosphide (InP), and use avariety of techniques to achieve mode-locking, which is the process of synchronizing the longitudinal modes of thelaser cavity.Mode-locked lasers are widely used in a variety of applications, including optical communications, optical sensing, and laser processing. They are particularly useful in applications that require high peak powers and short pulse durations, such as in nonlinear optics and ultrafast spectroscopy.There are several different techniques that can be usedto achieve mode-locking in semiconductor lasers. One common technique is to use an external cavity, which consists of a laser diode and an external resonator. The laser diode is used to generate the optical gain, while the external resonator is used to provide feedback and control the mode-locking process. Another technique is to use a saturable absorber, which is a material that absorbs light at low intensities but becomes transparent at high intensities.The saturable absorber is placed inside the laser cavityand acts to selectively suppress certain modes of the laser, leading to mode-locking.The performance of semiconductor MLLs is characterized by a number of parameters, including the pulse duration,the repetition rate, the average power, and the peak power. The pulse duration is the duration of the individual light pulses, and is typically measured in picoseconds or femtoseconds. The repetition rate is the rate at which the pulses are emitted, and is typically measured in gigahertz. The average power is the average power of the laser output, and is typically measured in milliwatts or watts. The peak power is the maximum power of the individual light pulses,and is typically measured in kilowatts or megawatts.Semiconductor MLLs are a rapidly developing field, and new advances are being made all the time. These lasers are becoming increasingly powerful and efficient, and arefinding new applications in a wide variety of fields.半导体锁模激光器。
基于石墨烯可饱和吸收的锁模光纤激光器研究
基于石墨烯可饱和吸收的锁模光纤激光器研究陈恺;祝连庆;姚齐峰;骆飞【摘要】An all-polarization-maintaining erbium-doped Q-switched mode-locked fiber laser by graphene saturable absorber mirror was reported.The characteristics of Q-switched mode-locked laser with monolayer graphene as saturable absorber were studied,and the laser output was obtained at the center wavelength of 1557.69 nm.Repetition rate of Q-switched envelope varied from 11.49 to 40.41 kHz,and the width of Q-switched envelope varied from 10.1 to 3.62 μs.When the inciden t pump power is 191.3 mW,the maximum average output power of the laser is 9.354 mW and the maximum light-light conversion efficiency is 4.89 ％.%报道了一种基于单层石墨烯可饱和吸收体调Q锁模的全保偏结构掺铒光纤激光器.研究了单层石墨烯作为可饱和吸收体实现调Q锁模后的激光特征,获得了中心波长1557.69 nm 的激光输出.调Q锁模脉冲包络重复频率11.49 ～ 40.41 kHz范围变化,包络宽度在10.1 ～3.62 μs范围变化.在泵浦功率为191.3 mW时,激光器最大输出平均功率9.354 mW,最大光-光转换效率为4.89％.【期刊名称】《激光与红外》【年(卷),期】2017(047)003【总页数】5页(P291-295)【关键词】调Q锁模光纤激光器;全保偏光纤结构;石墨烯饱和吸收镜【作者】陈恺;祝连庆;姚齐峰;骆飞【作者单位】北京信息科技大学光电信息与仪器北京市工程研究中心,光电测试技术北京市重点实验室,北京100016;北京信息科技大学光电信息与仪器北京市工程研究中心,光电测试技术北京市重点实验室,北京100016;北京信息科技大学生物医学检测技术及仪器北京实验室,北京100192;北京信息科技大学光电信息与仪器北京市工程研究中心,光电测试技术北京市重点实验室,北京100016;北京信息科技大学光电信息与仪器北京市工程研究中心,光电测试技术北京市重点实验室,北京100016【正文语种】中文【中图分类】TN248脉冲光纤激光器具有结构紧凑、体积小、泵浦效率高、光束质量好等优势,广泛应用在加工、通讯、医疗等领域。
调Q锁模运转的全固态TmLuAG陶瓷激光器
第50卷第4期V〇1.50No.4红外与激光工程Infrared and Laser Engineering2021年4月Apr.2021调Q锁模运转的全固态T m:L uA G陶瓷激光器陈晨1二3,许强i孙锐1A张亚妮康翠萍\张明霞2,袁振2,令维军2(1.宝鸡文理学院物理与光电技术学院，陕西宝鸡721016;2.天水师范学院激光技术研究所，甘肃天水741001;3.宝鸡市超快激光和新材料工程技术研究中心，陕西宝鸡721016;4.陕西科技大学文理学院，陕西西安710021)摘要：采用垂直生长法制备的氧化石墨浠（Grapheneoxide，GO)作为可饱和吸收体，利用典型“X”型折叠腔在全固态Tm:Lu3Al5012(Tm:LuAG)陶瓷激光器中实现了调Q锁模运转。
以790 nm激光二极 管（Laser diode,LD)作为泵浦源，当泵浦功率大于8 W时，激光器进入稳定的调Q锁模状态。
当输出 镜透过率为5%时，连续光最高输出功率为714 mW,斜效率为4.94%。
当泵浦达到16 W时，激光器最 大输出功率为200 mW,光谱中心波长为2024 nm,脉冲宽度约为695 ps,对应的锁模脉冲重复频率为 108.7 MHz,调Q包络中锁模脉冲的调制深度接近100%该2 pm超短脉冲激光器在生物医学和激光 通讯等领域具有非常重要的应用D关键词：Tm:LuAG陶瓷激光器；氧化石墨烯可饱和吸收体；调Q锁模；调制深度中图分类号：TN248.1 文献标志码：A DOI：10.3788/IRLA20190563Q-switched mode-locked all-solid-state Tm:LuAG ceramic laserChen Chen1,2,3,Xu Qiang1-3*,Sun Rui1,2,Zhang Ya'ni14.Kang Cuiping1.Zhang Mingxia2,Yuan Zhen2,Ling W eijun2(1. Institute of Physics and Optoelectronics Technology, Baoji University of Arts and Sciences, Baoji 721016, China;2. Institute of Laser Technology, Tianshui Nonna! University, Tianshui 741001, China;3. Baoji Engineering Technology Research Center on Ultrafast Laser and New Materials, Baoji 721016, China;4. School of Arts and Sciences, Shaanxi University of Science & Technology, Xi'an 710021, China)Abstract:Using graphene oxide (GO)by vertical growth m ethod as saturable absorber,an all-solid-state Q-switched m ode-locked Tm:L u3A15012 (Tm:LuAG)ceram ic laser with typical 'X'folded cavity was firstly dem onstrated.A790 n m laser diode(LD)was used as th e pum ping source.W hen th e pum ping power was greater th an8 W,th e laser en tered a stable Q-switched m ode-locked state.W hen th e ou tp u t m irror was5%, th e m axim um ou tp u t power of continuous light was714 mW,and th e oblique efficiency was4.94%. W hen th e pum ping power reached 16 W,th e m axim um ou tp u t power of th e laser was 200 mW,th e corresponding repetition frequency of m ode-locked pulse was 108.7 MHz,an d th e m odulation dep th of m ode locked pulse in Q-switched envelope was close to100%. The 2 ja m u ltrash ort pulsed laser h as im p ortan t applications in biom edicine and laser com m unication.收稿日期:2019-12-10;修订日期:2020-02-04基金项目:_家自然科学基金（11774257, 6丨564008, 11647008, 11504416);陕两省国际科技合作与交流计划项目（2021KW-39);宝鸡市重大科技专项计划项目（2015CXNL-1-3);天水市科技支撑计划自然科学基金项目（2018-FZ】HIC-3392);天水师范学院研究生创新引导项目（TYCX1901)第4期红外与激光工程第50卷Key words:Tm:LuAG ceram ic laser;graphene oxide saturable absorber;Q-switched m ode-locking;m odulation d ep th〇引言固体激光器的调Q锁模运转具有较高的峰值功 率和脉冲能量，已应用于生物医疗、材料微加工、表 面工程、太赫兹光学和激光雷达1121等重要领域。
Quantum_Dot
定义量子点(quantum dot)是准零维(quasi-zero-dimensional)的纳米材料，由少量的原子所构成。
粗略地说，量子点三个维度的尺寸都在100纳米(nm)以下，外观恰似一极小的点状物，其内部电子在各方向上的运动都受到局限，所以量子局限效应(quantum confinement effect)特别显著。
研究历史现代量子点技术要追溯到上世纪70年代中期，它是为了解决全球能源危机而发展起来的。
通过光电化学研究，开发出半导体与液体之间的结合面，以利用纳米晶体颗粒优良的体表面积比来产生能量。
初期研究始于上世体80年代早期2个实验室的科学家:贝尔实验室的Louis E.Brus博士和前苏联Yoffe研究所的AlexanderEfros和A.I.Ekimov博士。
Brus博士与同事发现不同大小的硫化镉颗粒可产生不同的颜色。
这个工作对了解量子限域效应很有帮助，该效应解释了量子点大小和颜色之间的相互关系，也同时也为量子点的应用铺平了道路。
1997年以来，随着量子点制备技术的不断提高，量子点己越来越可能应用于生物学研究。
1995年，AlivisatosI.Z.]和Nie两个研究小组首次将量子点作为生物荧光标记，并且应用于活细胞体系，他们解决了如何将量子点溶于水溶液，以及量子点如何通过表面的活性基团与生物大分子偶联的问题，由此掀起了量子点的研究热潮。
主要性质(1)量子点的荧光寿命长。
有机荧光染料的荧光寿命一般仅为几纳秒(这与很多生物样本的自发荧光衰减的时间相当）。
而量子点的荧光寿命可持续数十纳秒（20ns一50ns)，这使得当光激发后，大多数的自发荧光已经衰变子点荧光仍然存在，此时即可得到无背景干扰的荧光信号。
(2)生物相容性好。
量子点经过各种化学修饰之后，可以进行特异性连接，其细胞毒性低，对生物体危害小，可进行生物活体标记和检测。
(3)量子点具有很好的光稳定性。
量子点的荧光强度比最常用的有机荧光材料“罗丹明6G”高20倍，它的稳定性更是“罗丹明6G”的100倍以上。
激光锁模技术ppt课件
冲在腔内往返运动，每当此脉冲行进到输出反射镜时，便有一
个锁模脉冲输出。
➢脉冲宽度，即脉冲峰值与第一个光强为零的谷值间的时间间隔
sin[(2N 1) t ] 0但sin(t ) 0 t (m n )
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4.7.1 锁模原理
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(t1) (t1
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零时通过的光每次都能无损耗的通过，会不断被放大，满足阈
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脉宽很窄，周期为T的脉冲序列输出。
损耗内调制锁模
➢从频率域模式耦合的角度来说明损耗调制锁模的原理。假设中心 频率 ν0 处的模首先振荡，其振幅调制后的电矢量为：
彼此独立的、随机的，所以总光场是各个模式光场的非相
干叠加。输出总光强是各个振荡模式光强之和，即 I Iq
输出光强随时间无规则起伏。
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4.7.1 锁模原理
核心思想：锁模技术让谐振腔中存在的纵模同步振荡，让各模的频率 间隔保持相等并使各模的初位相保持为常数，激光器输出在时间上有 规则的等间隔的短脉冲序列。
实现锁模的方法
在一般激光器中，各纵模振荡互不相关，各纵模 相位没有确定的关系。并且，由于频率牵引效应， 相邻纵模的频率间隔并不严格相等。因此为了得到 锁模超短脉冲，须采取措施强制各纵模初位相保持 确定关系，并使相邻模频率间隔相等。
• 主动锁模 • 被动锁模 • 自锁模
4.7.2 主动锁模
在自由运转的激光器谐振腔中加入受外界信号控制的调制器， 对激光输出进行振幅或相位调制，实现各个纵模振动同步，叫 作主动锁模。 1. 振幅调制（损耗内调制锁模） ➢如图(4-31)所示，在谐振腔中插入一个电光或声光损耗调制器。 设调制周期为 Tm 2 Ω 2L c ，调制频率 νm c 2L (恰为纵 模频率间隔)
光纤激光器锁模原理介绍
光纤激光器锁模原理介绍Lasers are devices that produce intense beams of monochromatic light through the process of stimulated emission of radiation. Fiber lasers, in particular, are a type of solid-state laser that uses an optical fiber as the gain medium. Their ability to produce high-quality beams of light with high efficiency makes them highly desirable for a variety of applications, including cutting, welding, drilling, and marking in the industrial sector.激光是通过受激辐射过程产生强烈的单色光束的设备。
光纤激光器是一种将光纤作为增益介质的固体激光器。
它们能够高效地产生高质量的光束，因此在工业领域的切割、焊接、钻孔和标记等应用中备受青睐。
One fundamental principle behind the operation of fiber lasers lies in the process of mode locking. Mode locking refers to the synchronization of the phases of the modes of the laser’s electromagnetic field. By doing so, the laser produces pulses of light with a very narrow linewidth and high peak power, which is advantageous for many applications.光纤激光器运作背后的一个基本原理是锁模过程。
QuantumDots（量子点概述）
In terms of actual formation, the process characteristically went like this: ten atomic layers of film would form smoothly. As more layers were deposited, the film broke up into tiny pyramid-shaped islands. With more layers, the pyramids self-organized and coarsened, and then became dome-shaped islands.
optical and optoelectronic devices, quantum computing, and information storage.
Semiconductors with QDs as Material for Cascade Lasers
Semiconductors with QDs as Material for IR Photodetectors
The size ,shape and number of electrons can be precisely controlled
Just as in an atom, the energy levels are quantized due to the confinement of electrons.
These huge pressures, as new layers are deposited, force the initially flat film to separate into dots and then pop up into the third dimension to relieve stress, rather than continue to grow against resistance in two dimensions.
LED前沿技术:量子点(Quantum Dot)LED
LED前沿技术：量子点(Quantum Dot)LED李相敏【期刊名称】《科技信息》【年(卷),期】2010(000)021【摘要】LED技术以其高效、环保、节能在照明行业异军突起,然而LED最新的一项前沿技--量子点LED技术的出现将把LED的应用推向全新的高度.本文介绍了量子点LED的工作原理、技术优势、以及广间的应用前景和范围.【总页数】1页(P40)【作者】李相敏【作者单位】长江大学,湖北,荆州,434100【正文语种】中文【相关文献】1.The Electron-Hole Pair in a Single Quantum Dot and That in a Vertically Coupled Quantum Dot [J], XIE Wen-Fang;ZHU Wu2.Influences of a Side-Coupled Triple Quantum Dot on Kondo Transport Through a Quantum Dot [J], 江兆潭;杨彦楠;秦志杰3.The Electron－Hole Pair in a Single Quantum Dot and That in a Vertically Coupled Quantum Dot [J], XIEWen-Fang;ZHUWu4.SURFACE MORPHOLOGY OF SELF-ASSEMBLED VERTICALLY STACKED InAs QUANTUM DOTS BY SIZE-CONTROLLED GROWTH [J], S.W.Li;K.Koike5.High performance Ga N-based hybrid white micro-LEDs integrated withquantum-dots [J], Feifan Xu;Xu Cen;Bin Liu;Danbei Wang;Tao Tao;Ting Zhi;Qi Wang;Zili Xie;Yugang Zhou;Youdou Zheng;Rong Zhang因版权原因，仅展示原文概要，查看原文内容请购买。
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Broadband high gain amplification
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Loss decreases with optical intensity
Subpicosecond pulses directly from a QD laser
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Performance of QDMLLs
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Applications & challenges
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Mode-locking techniques
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Three main forms of mode-locking
Direct modulation of the gain section with a frequency equal to the repetition frequency of the cavity.
Optical communication systems
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Optical clocks for computer motherboards Biophotonics applications
Deploying a higher number of QD layers in the active region Using colliding-pulse mode-locking
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Ultrafast carrier dynamics — QD lasers
• Requiring low current to initiate lasing • Insensitive to temperature changes • Routinely grown on GaAs substrates • Strongly suppressed carrier diffusion • Exploiting GS and ES bands
Application: QD-SOA • Small size • High gain (> 18 dB) • Ultrashort pulses • Broad spectral range • High repetition rates (distortion-free)
[1]Rafailov E U, Loza-Alvarez P, Sibbett W, et al. Amplification of femtosecond pulses over by 18 dB in a quantum-dot semiconductor optical amplifier[J]. Photonics Technology Letters IEEE, 2003, 15(8):1023-1025. [2]Rafailov E U, Cataluna M A, Sibbett W. Mode-locked quantum-dot lasers[J]. Nature Photonics, 2007, 1(1):395-401.
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High repetition rates
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Thank you!
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Mode-locked quantum-dot lasers
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Outline
Introduction of quantum dots Application of quantum dots Introduction of mode-locking Passive mode-locking lasers Performance of QDMLLs Applications of QDMLLs
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Quantum confinement
Step-like density of states
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Using a saturable absorber incorporated into the laser, and providing the shortest pulses of all three techniques. Pulse generation is driven by an RF current imposed on the gain or absorber section, whereas further shaping and shortening is assisted by a saturable absorber.
• Broadband high gain amplification • Ultrafast carrier dynamics
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Quantum dots
• Zero-dimensional; • Nanoparticles/structures, size: ~2-10nm • Composed of groups II-VI, III-V, and IV-VI materials
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Passive mode-locking of lasers diodes
• A saturable absorber is incorporated into the laser cavity • In practical terms, it can be monolithically integrated into a semiconductor laser, by electrically isolating one section of the device