Yishan Wang

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (97)173.36 Total impact

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    ABSTRACT: Perfect linkage of dual frequency combs based on all polarization-maintaining femtosecond fiber lasers is demonstrated. By employing two independent tracking feedback controlling circuits, the repetition frequency (fr) and the carrier-envelope offset frequency (fceo) of the slave frequency comb track the master's fr and fceo , respectively. The correlation coefficients of the dual fr 's and the dual fceo 's are up to 0.99 and 0.98, which indicate an ideal linkage between the dual frequency combs. To the best of our knowledge, this is the first report about linkage of dual frequency combs.
    No preview · Article · Dec 2015 · IEEE Photonics Technology Letters
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    Weiman Jiang · Jing Li · Jie Tang · Yishan Wang · Wei Zhao · Yixiang Duan
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    ABSTRACT: A two-dimensional self-consistent fluid model was employed to investigate the spatiotemporal nonlinear behavior in an argon glow-like/Townsend-like dielectric-barrier discharge (DBD) at atmospheric pressure. The discharge is characterized by a major current pulse with a residual one ahead per half cycle of the external voltage. The two current pulses are operated in glow mode, but with Townsend mode between them. Contrasting spatial discharge structures are complementarily presented not only at two current pulses in the same half cycle but also during the discharge in the two adjacent-half cycles, resulting in the formation of a unique nested complementary pattern each cycle. This peculiar behavior mainly lies in the fact that sufficient charged particles are trapped in the gas gap due to the last discharge and able to dominate the subsequent discharge through the "spatial memory effect". The charge transport regime reveals that this nested complementary pattern is presented only in a limited range of driving frequency.
    Preview · Article · Nov 2015 · Scientific Reports
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    ABSTRACT: Based on the normalized spatiotemporal Lugiato–Lefever equation, the evolutions of cosine-modulated stationary fields relating to the generation of single-free spectral range (FSR) or multi-FSR Kerr frequency combs in a micro-resonator with anomalous dispersion are studied numerically. The research results show that a single-FSR comb arises when a dissipative soliton pulse or multiple nonequidistant soliton pulses form in the cavity. Compared with the smooth and regular spectral structure of a single soliton pulse, the comb corresponding to the uneven distribution of multiple soliton pulses exhibits a complex and irregular profile. When the stable intracavity field consists of a " roll " Turing pattern or N …N > 1† evenly distributed soliton pulses separated by 2π∕N , multi-FSR combs can be generated. In the case of the " roll " Turing pattern solution, it is found that third-order dispersion could modify the comb mode spacing and decrease the intensity of high-order comb modes. For the situation of multiple soliton pulse generation, the simulation results indicate that both the number and locations of the soliton pulses can be actively controlled through the careful selection of modulation frequency. In addition, for the selected cosine-modulated initial field profile, only those modes with the mode numbers being equal to an integer multiple of N can be greatly amplified by the parametric gain during propagation in the microresonator. This process eventually leads to the formation of a N-FSR frequency comb.
    Full-text · Article · Oct 2015 · Applied Optics
  • Jie Tang · Weiman Jiang · Jing Li · Yishan Wang · Wei Zhao · Yixiang Duan
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    ABSTRACT: A diffuse direct-current glow discharge was realized with low energy consumption and high energy utilization efficiency at atmospheric pressure. The formation of diffuse discharge was demonstrated by examining and comparing the electrical properties and optical emissions of plasmas. In combination with theoretical derivation and calculation, we draw guidelines that appearance of nitrogen ions at low electron density is crucial to enhance the ambipolar diffusion for the expansion of discharge channel and the increasing ambipolar diffusion near the cathode plays a key role in the onset of diffuse discharge. An individual-discharge-channel expansion model is proposed to explain the diffuse discharge formation.
    No preview · Article · Aug 2015 · Applied Physics Letters
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    ABSTRACT: We report a highly sensitive refractive index (RI) sensor in the aqueous solution, which is based on an 81°-tilted fiber grating structure inscribed into a thin cladding fiber with 40 μm cladding radius. The numerical analysis has indicated that the RI sensitivity of cladding resonance mode of the grating can be significantly enhanced with reducing cladding size. This has been proved by the experimental results as the RI sensitivities of TM and TE resonance peaks in the index region of 1.345 have been increased to 1180 nm/RIU and 1150 nm/RIU, respectively, from only 200 and 170 nm/RIU for the same grating structure inscribed in standard telecom fiber with 62.5-μm cladding radius. Although the temperature sensitivity has also increased, the change in temperature sensitivity is still insignificant in comparison with RI sensitivity enhancement.
    No preview · Article · Jul 2015 · Journal of Lightwave Technology
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    ABSTRACT: We demonstrate an all polarization-maintaining (PM) fiber-based optical frequency comb and provide the detailed environmental stability analysis results. The frequency comb has been built by commercial available PM fiber completely, and its static uncertainty in optical domain is 350 Hz in 1 s when referenced to a low noise oven controlled crystal oscillator. The acoustic resonant frequencies of the system have been measured. It is proved that acoustic-vibration induced phase noise could be eliminated by low pass vibration-isolation structure. Further, the existence of the optimum working temperature is illustrated. At this temperature (289.6 K), the out-loop integrated phase noise of f<sub>r</sub> and the temperature-drift induced instability of f<sub>CEO</sub> reach the lowest level 31.6 μrad and 0 kHz/(mW∙K) respectively. Finally, the system is proved to be stable under different humidity (18% ~80%) by a 240-day-long record of the f<sub>CEO</sub>.
    No preview · Article · Jun 2015 · Optics Express
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    Xianglian Liu · Hushan Wang · Yishan Wang · Zhijun Yan · Lin Zhang
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    ABSTRACT: We experimentally demonstrate an all-fiber single-polarization dual-wavelength Yb-doped fiber laser passively mode-locked with a 45°-tilted fiber grating for the first time. Stable dual-wavelength operation exhibits double-rectangular spectral profile centered at 1033 and 1053 nm, respectively. The 3 dB bandwidth of each rectangular optical spectrum is estimated as 10 nm. The separation of two fundamental repetition rates is 6 kHz. By employing the 45° TFG with the polarization-dependent loss of 33 dB, output pulses with 27 dB polarization extinction ratio are implemented in the experiment. The single pulse centered at 1053 nm is researched by using a filter at the output port of the laser, and the experimental results denote that the output ps pulses are highly chirped. The formation mechanism of dual-wavelength operation is investigated.
    Full-text · Article · Jun 2015 · Laser Physics Letters
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    ABSTRACT: We report a refractive index (RI) and liquid level sensing system based on a hybrid grating structure comprising of a 45° and an 81° tilted fiber gratings (TFGs) that have been inscribed into a single mode fiber in series. In this structure, the 45°-TFG is used as a polarizer to filter out the transverse electric (TE) component and enable the 81°-TFG operating at single polarization for RI and level sensing. The experiment results show a lower temperature cross-sensitivity, only about 7.33 pm/°C, and a higher RI sensitivity, being around 180 nm/RIU at RI=1.345 and 926 nm/RIU at RI=1.412 region, which are significantly improved in comparison with long period fiber gratings. The hybrid grating structure has also been applied as a liquid level sensor, showing 3.06 dB/mm linear peak ratio sensitivity.
    No preview · Article · Apr 2015 · Optics Communications
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    ABSTRACT: A spectro-temporal filtering method is proposed to increase the contrast ratio of chirped pulses. The advantages of this method include easy cascading, high transmission, and it can also be used in the high-energy chirped pulse amplifier (CPA) system. The effectiveness of the proposed method was experimentally verified by operating the spectro-temporal filtering method on a Ti:sapphire CPA system and then measuring the contrast ratio of pulse based on optical Kerr gate effect(OKG). The measuring result demonstrated that, after passing through one-stage spectro-temporal filtering system with transmittance up to 70%, the contrast ratio of the pulse was improved by an order of magnitude.
    Full-text · Article · Jan 2015 · Journal of Modern Optics
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    Weiman Jiang · Jie Tang · Yishan Wang · Wei Zhao · Yixiang Duan
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    ABSTRACT: A direct-current-driven plasma jet is developed by applying a longitudinal electric field on the flowing argon at ambient air. This plasma shows a torch shape with its cross-section increased from the anode to the cathode. Comparison with its counterparts indicates that the gas flow plays a key role in variation of the plasma structure and contributes much to enlarging the plasma volume. It is also found that the circular hollow metal base promotes generation of plasma with a high-power volume density in a limited space. The optical emission spectroscopy (OES) diagnosis indicates that the plasma comprises many reactive species, such as OH, O, excited N2, and Ar metastables. Examination of the rotational and vibrational temperature indicates that the plasma is under nonequilibrium condition and the excited species OH(A 2Σ+), O(5P), and N2(C 3Πu) are partly generated by energy transfer from argon metastables. The spatially resolved OES of plasma reveals that the negative glow, Faraday dark space, and positive column are distributed across the gas gap. The absence of the anode glow is attributed to the fact that many electrons in the vicinity of the anode follow ions into the positive column due to the ambipolar diffusion in the flowing gas.
    Full-text · Article · Sep 2014 · Scientific Reports
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    Wei Zhao · Xiaohong Hu · Yishan Wang
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    ABSTRACT: Three kinds of pulse amplification techniques including chirped-pulse amplification (CPA), parabolic pulse amplification, and divided-pulse amplification (DPA) based on rare-earth doped fiber gain medium are reviewed. Large core area fiber and cladding-pumping technique compose the foundation of high average power, high pulse energy fiber CPA technology. Femtosecond pulses have been demonstrated at average powers of up to 830 W, pulse energies of up to 2.2 mJ and compressed pulse duration of 23 fs from different fiber CPA systems. The state-of-the-art performance of fiber CPA system to date is the simultaneous generation of 530 W, 1.3 mJ compressed femtosecond pulses at 400 kHz repetition rate. The balance between fiber gain, dispersion and nonlinearity is required for the self-similar propagation and thus the formation of pulses with parabolic intensity profile. Sub-33 fs pulses were demonstrated from a gain-cascaded parabolic amplification system. A newly emerging DPA technique is also reviewed. In addition, the applications of pulsed fiber amplifiers in the areas of supercontinuum generation and material micromachining system are also introduced.
    Full-text · Article · Sep 2014 · IEEE Journal of Selected Topics in Quantum Electronics
  • Dengke Wu · Junfang He · Changjun Zhu · Yishan Wang · Wei Zhao
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    ABSTRACT: In this paper, pulse contrast was measured for femtosecond lasers with low-repetition-rate (40 Hz) using optical Kerr gate as a sampler. The results show that, without attenuator, dynamic range as high as 104 was achieved, with a scanning range of 126 ps and a temporal sampling interval of 6.3 fs. Moreover, the method suits for measuring laser pulse contrast in wide spectrum range.
    No preview · Article · Sep 2014 · Journal of Nonlinear Optical Physics & Materials
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    ABSTRACT: We study a single-wall carbon nanotube (SWNT) Polyvinyl alcohol (PVA) composite as a saturable absorber (SA) for pulse generation in Yb-doped fiber lasers. The saturable absorption and optical limiting (OL) characteristics of the SWNT device are investigated. By combing these two nonlinear effects, we find out for the first time, to the best of our knowledge, that mode-locking can be obtained in the dissipative soliton regime at low pumping followed by Q-switching at high pumping, which is quite different from conventional pulse dynamic evolutions. The Q-switched state operating at higher pump powers is due to the OL effect. The inverted operating fiber laser can be applied in various potential applications such as versatile material processing, optical communication and radar system etc.
    No preview · Article · Jul 2014 · Optics Express
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    ABSTRACT: Phase noise is very important for the ultrafast pulse application in telecommunication, ultrafast diagnose, material science, and biology. In this paper, two types of carbon nano-materials, single-wall carbon nanotube and graphene oxide, are investigated for noise suppression in ultrafast photonics. Various properties of the wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the phase noise of the ultrafast pulses. A reduced-noise femtosecond fiber laser is experimentally demonstrated by optimizing the above parameters of carbon material based SAs. The phase noise reduction more than 10 dB at 10 kHz can be obtained in the experiments. To our knowledge, this is the first time that the relationship between different carbon material based SAs and the phase noise of mode-locked lasers has been investigated. This work will pave the way to get a high-quality ultrashort pulse in passively mode-locked fiber lasers.
    Full-text · Article · Jul 2014
  • YongGang Wang · YiShan Wang · XiaoJun Zhang · Qiao Wen
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    ABSTRACT: Carbon nanotubes in heavy water (deuteroxide, D2O) dispersion was fabricated and used as absorber in Q-switched Nd:YVO4 laser for the first time to the best of our knowledge. Such liquid absorber has the virtues of good optical transparency, high heat dissipation and non contact damage. The shortest pulse width of the Q-switched laser is 709 ns, corresponding to 80 kHz repetition rate. The maximum output power of passively Q-switched laser is 214 mW.
    No preview · Article · Jun 2014 · Optics Communications
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    Xiaohui Li · Yishan Wang · Wei Zhang · Wei Zhao
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    ABSTRACT: We have observed soliton molecules with variable modulation depth of spectra in a passively mode-locked dispersion-managed Yb-doped fiber laser. The soliton molecule we experimentally investigated presents diatomic and tetratomic types. With the enhancement of pump power, the laser alternately operates at solitons molecule, temporal-separation-oscillation solitons, and harmonic mode-locked states. Moreover, the phase of solitons molecule is only locked at low pump, and excess pump would cause phase vibration.
    Full-text · Article · May 2014 · Laser Physics Letters
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    Qiao Wen · XiaoJun Zhang · YiShan Wang · HanBen Niu
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    ABSTRACT: Liquid saturable absorbers have some advantages in some aspects over solid saturable absorbers. In this paper, graphene oxide in heavy water (deuteroxide, D2O) dispersion was fabricated and used as absorber in Q-switched Nd:YAG laser for the first time, to the best of our knowledge. The shortest pulse width of the Q-switched laser is 523 ns, corresponding to a repetition rate of 92.9 kHz. The maximum peak power of Q-switched pulse is 6.6 W. Such a liquid absorber has the virtues of good optical transparency, high heat dissipation, and no contact damage.
    Full-text · Article · Apr 2014 · IEEE Photonics Journal
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    ABSTRACT: A diode-pumped passively Q-switched Nd:GGG laser with a single-walled carbon nanotube as saturable absorber has been realized. A maximum average output power of 1.24 W and a minimum pulse duration of 49.8 ns were obtained at the incident pump power of 7.69 W. Corresponding to a maximum single pulse energy and a highest peak power were 4.3 \(\upmu \hbox {J}\) and 85 W, respectively. The pulse repetition rates varied from 62 to 292 kHz versus the increase of the incident pump power.
    No preview · Article · Mar 2014 · Optical and Quantum Electronics
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    ABSTRACT: A diode-end-pumped passively Q-switched Nd:GGG laser with a double-walled carbon nanotube (DWCNT) saturable absorber is demonstrated for the first time. A maximum output power of 1.03 W and a minimum pulse duration of 24.3 ns with a highest peak power of 121 W were obtained. The pulse repetition rate varied from 122 to 350 kHz as the pump power increased. The experimental results show that DWCNT is an excellent saturable absorber for passive Q-switched lasers.
    No preview · Article · Feb 2014 · Laser Physics Letters
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    ABSTRACT: The demonstration is reported of a diode-pumped passively Q-switched Nd:LuVO4 laser at 1064 nm using a transmission-type graphene oxide as the saturable absorber. The graphene oxide saturable absorber with a modulation depth of 10% was fabricated using a vertical evaporation method. With a pump of 11.5 W, a maximum output power of 1.353 W was obtained with 186-ns pulse duration and 336.7-kHz repetition rate, corresponding to a maximum pulse energy of 4 μJ per pulse.
    No preview · Article · Jan 2014 · Journal of Modern Optics

Publication Stats

551 Citations
173.36 Total Impact Points


  • 2000-2015
    • Chinese Academy of Sciences
      • State Key Laboratory of Transient Optics and Photonics
      Peping, Beijing, China
  • 1999-2015
    • State Key Laboratory Of Transient Optics And Photonics
      Ch’ang-an, Shaanxi, China
  • 2014
    • Shenzhen University
      • College of Optoelectronic Engineering
      Bao'an, Guangdong, China