Qirong Xing
Tianjin University
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Publication
Featured researches published by Qirong Xing.
Applied Physics Letters | 2010
Jianqiang Gu; Ranjan Singh; Zhen Tian; Wei Cao; Qirong Xing; Mingxia He; Jingwen W. Zhang; Jiaguang Han; Hou-Tong Chen
We characterize the behavior of split ring resonators made up of high transition temperature yttrium barium copper oxide superconductor using terahertz time-domain spectroscopy measurements and numerical simulations. The superconductor metamaterial is found to show a remarkable change in the transmission spectra at the fundamental inductive-capacitive resonance as the temperature dips below the critical transition temperature. This resonance switching effect is normally absent in traditional metamaterials made up of regular metals. The temperature-dependent resonance behavior of the superconducting metamaterial would lead to development of low loss terahertz switches at cryogenic temperatures.
Optics Express | 2009
Jiaguang Han; Jianqiang Gu; Xinchao Lu; Mingxie He; Qirong Xing
We present a systematic numerical study of a metal-dielectric-metal sandwich plasmonic structure for broadband resonant transmission at terahertz frequencies. The proposed structure consists of periodic slotted metallic arrays on both sides of a thin dielectric substrate and is demonstrated to exhibit a broad passband transmission response. Various design considerations have been investigated to exploit their influence on the transmission passband width and the center resonance frequency. The structure ensures a broadband transmission over a wide range of incident angles.
Optics Express | 2009
Jianqiang Gu; Jiaguang Han; Xinchao Lu; Ranjan Singh; Zhen Tian; Qirong Xing
We present a systematic study of a close-ring pair based freestanding metamaterial fabricated by double-layer, self-aligned photolithography. Terahertz time-domain spectroscopy transmission measurements and numerical simulations have revealed negative index of refraction in the frequency range of 0.66-0.90 THz under normal wave incidence. The observed resonance behaviors can be well explained by a theoretical circuit model. The electromagnetic properties and the figure of merit of such close-ring metamaterials are also explored in terms of geometrical parameters of the unit cell with a goal of providing optimized design for three-dimensional metamaterials and potential device applications.
IEEE Photonics Technology Letters | 2008
Youjian Song; Minglie Hu; Changlei Wang; Zhen Tian; Qirong Xing; Lu Chai; Chingyue Wang
A high pulse energy passively mode-locking fiber laser operating in the soliton-like regime is demonstrated. The laser is based on a linear cavity design. A segment of Yb-doped single-polarization large-mode-area photonic crystal fiber serves as the gain medium, and the self-starting mode-locking is achieved by a high contrast semiconductor saturable absorber mirror. The laser directly generates 600-fs pulses with 900 mW of average power at a repetition rate of 47.3 MHz, corresponding to a single pulse energy of 19 nJ. Furthermore, this fiber laser is directly used for pumping ZnTe to generate broadband terahertz radiation, resulting in a compact terahertz source.
Optics Letters | 2010
Zhen Tian; Ranjan Singh; Jiaguang Han; Jianqiang Gu; Qirong Xing; Judy Z. Wu
We demonstrate a superconductor array of subwavelength holes with active thermal control over the resonant transmission induced by surface plasmon polaritons. The array was lithographically fabricated on a high-temperature yttrium barium copper oxide superconductor and characterized by terahertz time-domain spectroscopy. We observe a clear transition from a virtual excitation of the surface plasmon mode to a real surface plasmon mode. The highly controllable superconducting plasmonic crystals may find promising applications in the design of low-loss, large- dynamic-range amplitude modulation and surface-plasmon-based terahertz devices.
Applied Physics Letters | 2008
Jixian Gong; Xueming Zhao; Qirong Xing; Fang Li; H. Li; Yanfeng Li; Lu Chai; Qingyue Wang; Aleksei M. Zheltikov
Femtosecond laser was employed to induce cell fusion. The interface between two protoplasts of Phaffia rhodozyma in contact was irradiated by femtosecond laser pulses with 1.38×104W for 0.25s. After about 20min, the fusion of cells became visible and finally two cells merged into one larger cell within 160min. Fusion rate at this power level was 80%. The experiments suggested the existence of threshold power for cell fusion induced by femtosecond laser. Regarding femtosecond laser pulses as a trigger, we present a hypothetical model for femtosecond laser-induced cell fusion.
Optics Communications | 1999
Qirong Xing; Lu Chai; Chingyue Wang
Regular, period-doubling, quasi-periodic and chaotic behavior in a self-mode-locked Ti:sapphire laser was observed under fixed pump power during alignment of the laser cavity.
IEEE Photonics Technology Letters | 2010
Feng Liu; Youjian Song; Qirong Xing; Minglie Hu; Yanfeng Li; Changlei Wang; Lu Chai; Aleksei M. Zheltikov; Chingyue Wang
We demonstrate a scalable, compact, high-power, and broadband terahertz (THz) source based on a cutting-edge large-mode-area photonic-crystal-fiber amplifier system. A 3-mm (110)-cut bulk GaP crystal was used as the THz emitter based on an optical rectification technique. Systematic optimization of the operation parameters allowed a THz output up to 150 μW to be achieved with an input laser power of 12 W in the GaP crystal.
Applied Physics Letters | 2006
Qirong Xing; Shuxin Li; Zhen Tian; Dong Liang; Ning Zhang; Liying Lang; Lu Chai; Qingyue Wang
Very deep metallic grating structures with subwavelength slits are processed to study the transmission properties of terahertz radiation pulses. The experiments have been performed with two samples. The delay of the terahertz pulses and the corresponding enhanced unresonant transmission spectra through the samples are observed. A simple interpretation is presented based on the combination of zero-order diffraction of the gratings with the coupling of the surface plasmon polaritons formed on the top and bottom of the gratings. The experimental results are in good agreement with theoretical calculations.
Optics Express | 2010
Zhen Tian; Abul K. Azad; Xinchao Lu; Jianqiang Gu; Jiaguang Han; Qirong Xing; Antoinette J. Taylor; John F. O’Hara
We present resonant terahertz transmission in a composite plasmonic film comprised of an array of subwavelength metallic patches and semiconductor holes. A large dynamic transition between a dipolar localized surface plasmon mode and a surface plasmon resonance near 0.8 THz is observed under near infrared optical excitation. The reversal in transmission amplitude from a stop-band to a pass-band and up to pi/2 phase shift achieved in the composite plasmonic film make it promising in large dynamic phase modulation, optical changeover switching, and active terahertz plasmonics.