共查询到19条相似文献,搜索用时 93 毫秒
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Under the condition of two different cases,the absorption of a pulsed probe field and its slow propagation in a triple semiconductor quantum well are investigated.The result shows that semiconductor medium becomes transparent due to the action of control field.Another result shows that by choosing appropriate physical parameters,the slow propagation of the input field can be achieved.The proposed scheme has some potential applications and may lead to the development of the controlled technique of optical buffers and optical delay lines. 相似文献
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Slow light supported by electromagnetically induced transparency effect in dispersive medium is extremely susceptible with respect to Doppler detuning.In this paper,the Doppler effect induced by rotating dispersive medium was considered and the effect of the velocity of rotating dispersive medium on the group velocity was studied.Based on a dispersive slow-light medium,a high sensitive optical rotation sensor for measuring absolute rotation is proposed and analysed.The sensitivity of the rotation sensor is the group delay between the counterpropagationed wave packets in the device,and scales directly with square of the group index which can reach 10 2-10 8 orders of magnitude by selecting a proper dispersive medium. 相似文献
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CuiXiu Xiong Hui Xu MingZhuo Zhao BaiHui Zhang Chao Liu Biao Zeng Kuan Wu BanXian Ruan Min Li HongJian Li 《中国科学:物理学 力学 天文学(英文版)》2021,(2)
We propose a simple quasi-continuous monolayer graphene structure and achieve a dynamically tunable triple plasmon-induced transparency(PIT)effect in the proposed structure.Additional analyses indicate that the proposed structure contains a selfconstructed bright-dark-dark mode system.A uniform theoretical model is introduced to investigate the spectral response characteristics and slow light-effects in the proposed system,and the theoretical and the simulated results exhibit high consistency.In addition,the influences of the Fermi level and the carrier mobility of graphene on transmission spectra are discussed.It is found that each PIT window exhibits an independent dynamical adjustability owing to the quasi-continuity of the proposed structure.Finally,the slow-light effects are investigated based on the calculation of the group refractive index and phase shift.It is found that the structure displays excellent slow-light effects near the PIT windows with high-group indices,and the maximum group index of each PIT window exceeds 1000 when the carrier mobility of graphene increases to 3.5 m^2 V^-1s^-1.The proposed structure has potential to be used in multichannel filters,optical switches,modulators,and slow-light devices.Additionally,the established theoretical model lays a theoretical basis for research on multimode coupling effects. 相似文献
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A large bandwidth photonic delay line using passive cascaded silicon-on-insulator microring resonators 下载免费PDF全文
This paper investigated the design and the characterization of a photonic delay line based on passive cascaded silicon-on-insulator (SOI) microrings.We considered the compromise of group delay,bandwidth and insertion loss.A 3-stage double channel side-coupled integrated spaced sequence of resonator (SCISSOR) device was optimized by shifting the resonance of each microring and fabricated with electron beam lithography and dry etching.The group delay was measured to be 17 ps for non-return-to-zero signals at different bit rates and the bandwidth of 78 GHz was achieved.The experiment result agreed well with our simulation. 相似文献
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We experimentally study the controllable generation of a beating signal using stored light pulses based on electromagnetically induced transparency(EIT) in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements. 相似文献
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Controllable beating signal using stored light pulseControllable beating signal using stored light pulseControllable beating signal using stored light pulse 下载免费PDF全文
We experimentally study the controllable generation of a beating signal using stored light pulses based on electro- magnetically induced transparency (EIT) in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements. 相似文献
7.
Backward wave oscillators (BWOs) driven by intense relativistic electron beams are very efficient means of producing high-power microwaves. However, the efficiency of conventional BWO is lower than 30%. An X-band oversized BWO with non-uniform slow wave structure is designed to improve RF output characteristics. In particle-in-cell simulation, a high power microwave with a power of 8.0 GW and efficiency of 40% is obtained, compared with that of 30% obtained in a conventional relativistic BWO. 相似文献
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A two-dimensional photonic crystal coupled-cavity waveguide is designed and optimized, the transmission spectrum is calculated by using the finite-difference time-domain method, and the group velocity of c/1856 is obtained. To our knowledge, this value of group velocity is the lowest group velocity in a photonic crystal waveguide calculated from its transmission spectrum so far. The result is confirmed by the photonic band structure calculated by using the plane wave expansion method, and it is found that the photonic crystal waveguide modes in a photonic band structure are in accordance with those in the transmission spectrum by using the finite-difference time-domain method. The mechanism of slow light in the coupled-cavity waveguide of photonic crystal is analysed. 相似文献
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Controllable time delay using slow/fast light in active fiber ring resonators with gain manipulation
We propose to generate controllable time delay using slow/fast light in fiber ring resonators with gain manipulation.The dispersion and group delay of active fiber ring resonator can be controlled by manipulating its gain level below the lasing threshold.Controllability of the negative group delay in the undercoupled regime and the positive group delay in the overcoupled regime is theoretically demonstrated.Besides,large group delay can be obtained accompanied by signal gain in active ring resonators.In addition,we describe wide bandwidth and large group delay in 4-stage cascaded ring resonators. 相似文献
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对基于光纤四波混频(FWM)波长转换和色散的慢光实现进行了详细和系统的实验研究.首先,实验测定了高非线性光纤中FWM带宽约为40 nm,从而确定了慢光的可调谐带宽;接着,在普通单模光纤和色散补偿光纤(DCF)中针对500 MHz正弦信号和100 ps短脉冲信号分别实现了34和198 ns的脉冲延迟,在DCF中还实现了209 ns的脉冲提前.讨论了增大延迟量的方法,指出随着宽带FWM波长转换的实现和大色散光纤的应用有望获得微秒量级的大延迟量,从而为高性能光纤延迟线和全光缓存器等应用提供支持.
关键词:
慢光
四波混频
色散 相似文献
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We experimentally study the generation and storage of double slow light pulses in a Pr3+:Y2SiO5 crystal. Under electromagnetically induced transparency, a single signal pulse is stored in the spin coherence of the crystal. By simultaneously switching on two control fields to recall the stored information, the spin coherence is converted into two slow light pulses with distinct frequencies. Furthermore, the storage and controlled retrieval of double slow light pulses are obtained by manipulating the control fields. This study of double slow light pulses may have practical applications in information processing and all-optical networks. vspace2mm 相似文献
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利用椭圆形孔替代传统光子晶体薄板波导中邻接波导的最内层两排圆孔构成一种新型低损耗光子晶体薄板光波导.该波导的群速度和群速度色散特性强烈依赖于波导中这两排邻接波导的椭圆孔的特性.借助波导导模展开方法,计算得到波导的能带结构和群指数,并分析了它们与椭圆孔的参数关系.通过优化这些椭圆孔的参数,可以增加光子晶体光波导导模在光锥以下的无固有传输损耗带宽,在2—45 nm 的带宽上实现无色散的常数群速度.这些理论结果将为低损耗低色散慢光波导的设计制造提供理论基础.
关键词:
光子晶体薄板波导
群速度
群指数
群速度色散 相似文献
17.
利用椭圆形孔替代传统光子晶体薄板波导中邻接波导的最内层两排圆孔构成一种新型低损耗光子晶体薄板光波导.该波导的群速度和群速度色散特性强烈依赖于波导中这两排邻接波导的椭圆孔的特性.借助波导导模展开方法,计算得到波导的能带结构和群指数,并分析了它们与椭圆孔的参数关系.通过优化这些椭圆孔的参数,可以增加光子晶体光波导导模在光锥以下的无固有传输损耗带宽,在2—45 nm 的带宽上实现无色散的常数群速度.这些理论结果将为低损耗低色散慢光波导的设计制造提供理论基础. 相似文献
18.
在考虑耦合器插入损耗的情况下,理论分析了环中环结构谐振腔的耦合谐振透明效应.利用迭代法推导了整个结构的透过系数和有效相移,从而得到考虑了插入损耗的该结构的色散.研究表明,整个结构的有效相移,群速度和带宽,可通过耦合器的插入损耗、环中环结构中环与环周长之间的倍数以及环的个数来控制,这在旋转传感、光学时延线、光缓存、滤波等方面的应用有重要意义.
关键词:
环中环结构
耦合谐振透明
色散
慢光 相似文献
19.
Abdurahman Ahmed Yonis Vadim Nickolaevich Mal nev Belayneh Mesfin Ali 《中国物理 B》2016,25(2):27801-027801
The propagation of narrow packets of electromagnetic waves(EMWs) in frequency dispersive medium with the consideration of the complex refractive index is studied. It is shown that counting in the dispersion of the complex refractive index within the context of the conventional expression of the group velocity of narrow wave packets of EMWs propagating in a dispersive medium results in the appearance of additional constraints on the group velocity, which dictates that the physically acceptable group velocity can only be realized in the case of a negligible imaginary part of the group index. In this paper, the conditions that allow one to realize the physically acceptable group velocity are formulated and analyzed numerically for the relevant model of the refractive index of a system of two-level atoms in the optical frequency range. It is shown that in the frequency band where superluminal light propagation is expected, there is a strong dispersion of the refractive index that is accompanied with strong absorption, resulting in a strongly attenuated superluminal light. 相似文献