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Zhu J.,Xidian University | Wang Z.,CAS Institute of Physics | Wang Q.,CAS Institute of Physics | Zhang Z.,CAS Institute of Physics | And 4 more authors.
Chinese Optics Letters | Year: 2012

We experimentally demonstrate a diode-pumped passively mode-locked femtosecond laser with Yb3+-doped yttrium lanthanum oxide ceramic. Mode-locking is achieved by using a semiconductor saturable absorber mirror, and intracavity dispersion is compensated by a pair of SF6 prisms. Laser pulses as short as 357 fs at a central wavelength of 1 075 nm are obtained. The maximum average output power is 670 mW under 4.5 W of pumping power with a slope efficiency of 20%. To the best of our knowledge, this is the shortest pulse generated from Yb-doped yttrium lanthanum oxide ceramic lasers with a sub-500 fs pulse duration. © 2012 Chinese Optics Letters.


Yan Y.,CAS Academy of Opto Electronics | Yan Y.,Beijing GK Laser Technology Co. | Fan Z.-W.,CAS Academy of Opto Electronics | Niu G.,Beijing GK Laser Technology Co. | And 2 more authors.
Chinese Physics Letters | Year: 2012

A 46-W laser diode end-pumped amplifier is demonstrated by using a SESAM passively mode-locked oscillator and a compact LD stack end-pumped slab amplifier. For the oscillator, a 5-W picosecond mode-locked laser with a repetition frequency of 79 MHz is obtained with beam quality factors of M 2 < 1.3. A beam shaping system made up of cylindrical lens is designed according to different sizes of the active medium in both directions, and a plane-plane cavity is used in the amplifier for high efficiency. At the absorbed pumping power of 174 W, the highest output power of 46 W is obtained with the slope efficiency of 29.5%. The beam quality factors M 2 in both directions are measured to be 1.43 and 1.76, respectively. © 2012 Chinese Physical Society and IOP Publishing Ltd.


Xu L.,Beijing Institute of Technology | Zhang H.,Beijing Institute of Technology | Mao Y.,Beijing Institute of Technology | Yan Y.,Beijing GK Laser Technology Company | And 2 more authors.
Applied Optics | Year: 2012

We demonstrated a laser-diode, end-pumped picosecond amplifier. With effective shaping of the seed laser, we achieved 73 W amplified laser output at the pump power of 255 W, and the optical-optical efficiency was about 28%. The beam propagation factors M2 measured at the output power of 60 W in the horizontal direction and the vertical direction were 1.5 and 1.4, respectively. © 2012 Optical Society of America.


Liu X.,CAS Academy of Opto Electronics | Fan Z.,CAS Academy of Opto Electronics | Shi Z.,CAS Academy of Opto Electronics | Ma Y.,CAS Academy of Opto Electronics | And 2 more authors.
Optics Express | Year: 2016

In this work, dual-core antiresonant hollow core fibers (AR-HCFs) are numerically demonstrated, based on our knowledge, for the first time. Two fiber structures are proposed. One is a composite of two single-core nested nodeless AR-HCFs, exhibiting low confinement loss and a circular mode profile in each core. The other has a relatively simple structure, with a whole elliptical outer jacket, presenting a uniform and wide transmission band. The modal couplings of the dual-core AR-HCFs rely on a unique mechanism that transfers power through the air. The core separation and the gap between the two cores influence the modal coupling strength. With proper designs, both of the dual-core fibers can have low phase birefringence and short modal coupling lengths of several centimeters. © 2016 Optical Society of America.


Zhu L.,CAS Shanghai Institute of Optics and fine Mechanics | Zhou C.,CAS Shanghai Institute of Optics and fine Mechanics | Wu T.,CAS Shanghai Institute of Optics and fine Mechanics | Jia W.,CAS Shanghai Institute of Optics and fine Mechanics | And 5 more authors.
Applied Optics | Year: 2010

We present a femtosecond off-axis digital holography for investigating the dynamic reversible surface change of a metal film induced by femtosecond laser pulses with fluences near the ablation threshold. A reflection Michelson interferometer (RMI) and a transmission Mach-Zehnder interferometer (TMZI) are integrated in the same setup for recording digital holograms. The RMI is used to measure the laserinduced surface deformation of the metal film, while the TMZI is used to analyze the refraction index change of the metal film induced by the femtosecond laser pulses. Experimental results show that both surface modification and refraction index change of chromium metal film can be observed when femtosecond laser pulses are below and above the ablation threshold. Based on the experimental results, the physical processes of the metal induced by femtosecond laser pulses are given qualitatively. © 2010 Optical Society of America.


Ma Y.,CAS Academy of Opto Electronics | Yu J.,CAS Academy of Opto Electronics | Niu G.,Beijing GK Laser Technology Co. | Zhao T.,CAS Academy of Opto Electronics | And 4 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2011

Average output power more than 50 W, 1064 nm picosecond laser with three power amplifier systems (LD double-pass amplifier, LD double end-pumped amplifier and LD single end-pumped amplifier) is reported. When input 6.67 W picosecond seed pulse, power amplifier's average power achieves to 53.7 W with optical-optical conversion efficiency of 30.07%, a pulse duration of 10.45 ps. By using of nonlinear crystal LBO for second harmonic generation (SHG) with high average power of 27.16 W, a repetition rate of 80 MHz, a pulse duration less than 10 ps, SHG efficiency higher than 50.58% are obtained. At premise of high SHG efficiency, the system guarantees against damaging SHG crystal, keeps uninterrupted running with stable power more than 8 h.


Yan Y.,CAS Academy of Opto Electronics | Yan Y.,Beijing GK Laser Technology Co. | Fan Z.W.,CAS Academy of Opto Electronics | Niu G.,Beijing GK Laser Technology Co. | And 2 more authors.
Laser Physics | Year: 2012

A powerful and stable LD end pumped Nd:YVO 4 passively mode-locking oscillator by SESAM was demonstrated. At the pumping power of 30 W, 7 W output was obtained with repetition rate of 79.5 MHz and pulse duration of 15 ps. The beam quality factors M 2 were measured to be 1.30 and 1.33, respectively. © Pleiades Publishing, Ltd., 2012.


Chang L.,Beijing University of Technology | Yang C.,Beijing University of Technology | Pang Q.S.,Beijing University of Technology | Ai Q.K.,Beijing University of Technology | And 5 more authors.
Laser Physics | Year: 2012

We report an 885 nm laser diode (LD) end-pumped high beam quality ( M x 2= 1.322, M y 2= 1.235) electro-optical Q-switched Nd:YAG laser with TEM 00-mode output for the first time. At the absorbed pump power of 59.5 W, a 22.7 W 1064 nm laser was achieved at 10 kHz repetition rate with optical-to-optical efficiency of 38.1%. The maximum pulse energy and shortest pulse width were 5.1 mJ and 14.5 ns at 2 kHz repetition rate, and the calculated peak power was 352 kW. © Pleiades Publishing, Ltd., 2012.


Ai Q.K.,Beijing University of Technology | Chen M.,Beijing University of Technology | Xu Y.,Beijing University of Technology | Chang L.,Beijing University of Technology | And 4 more authors.
Laser Physics | Year: 2012

We have demonstrated an all-diode-pumped Nd:YLF laser amplifier that produces 20.8 mJ pulses of 12.9 ps duration at 10 Hz repetition rate. The laser system consists of a mode-locking oscillator, a regenerative amplifier and a five-pass amplifier. The small-angle off-axis five-pass configuration combining with the gradual expansion of the laser beam cross section makes the amplifier compact and effective. © Pleiades Publishing, Ltd., 2012.


Zhang F.,Nankai University | Chen P.,Nankai University | Zhang L.,Nankai University | Mao S.-C.,Nankai University | And 6 more authors.
Applied Physics Letters | Year: 2012

Wavelength-dependent surface-enhanced Raman spectra of methylene blue adsorbed on rough submicrometer silver particles were measured. Results revealed a high enhancement factor (10 5 ∼ 10 7), especially in the long-wavelength region. Investigation on the far- and near-field optical properties of the particles showed a remarkably enhanced dipole plasmon resonance due to the presence of a rough particle surface. Through analyzing the plasmon resonance modes and the superposition of radiation fields, we found that the rough surface-induced field superposition results in the redistribution of optical fields around the particle, which becomes a key factor responsible for the high enhancement effect of metal particles. © 2012 American Institute of Physics.

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