Highly transparent 5 at.% Yb:Y₂O₃ ceramics were fabricated by using a combination method of vacuum sintering and hot isostatic pressing (HIP). Co-precipitated Yb:Y₂O₃ powders, with 1 at.% ZrO₂ as the sintering aid, were used as the starting material. The Yb:Y₂O₃ ceramics, vacuum sintered at 1700 °C for 2 h and HIPed at 1775 °C for 4 h, exhibited small grain size of 1.9 μm and highly dense microstructure. In-line optical transmittance of the ceramics reached 83.4% and 78.9% at 2000 and 600 nm, respectively. As the ceramic slab was pumped by a fiber-coupled laser diode at about 940 nm, a maximum output power of 0.77 W at 1076 nm was achieved, with a corresponding slope efficiency of 10.6%.

Jun Wang;Jie Ma;Jian Zhang;Peng Liu;Dewei Luo;Danlei Yin;定元 汤;Ling Bing Kong

Optical Materials

2017-9

Bound states in a passively mode locked fiber soliton laser were experimentally observed. The observed bound states are very stable. Once formed, they remained there for several hours even in a noisy environment. Trains of bound states that have the same soliton separation were also found.

定元 汤;P. D. Drummond;W. S. Man;H. Y. Tam;M. S. Demokan

2000

We demonstrated a Q-switched Ho:YAG ceramic laser operating at 2097 nm. The Ho:YAG ceramic laser was resonantly pumped by a Tm:YLF laser at 1908 nm. The laser performance with two Ho-doping concentrations of Ho:YAG ceramics in a U-shaped resonator was studied. Different pump spots were investigated to obtain high extract efficiency. The wavelength of Ho:YAG ceramic laser was tuned from 2090.70 nm to 2098.10 nm. The Q-switched pulse energy were 9.6 mJ at a pulse repetition frequency (PRF) of 200 Hz and 10.2 mJ at a PRF of 100 Hz, respectively. The beam quality M² factors were measured to be less than 1.1 in both directions.

Lei Wang;春清 高;Mingwei Gao;Yan Li;Fuyong Yue;Jian Zhang;定元 汤

Optics Express

2014-1-13

Antiphase dynamics of an optically pumped [Formula Presented] bidirectional ring laser under the chaotic, phase-sensitive mode coupling is experimentally observed. Our experimental result suggests strongly that the dynamics is a generic behavior of the laser.

定元 汤;N. R. Heckenberg

Physical Review A - Atomic, Molecular, and Optical Physics

1997

We report a high-efficiency diode-end-pumped polycrystalline Yb:Y2O3 ceramic laser. Pumped by a 976 nm laser diode bar and with an absorbed pump power of 2.8W, cw output power of 1.74W at 1078 nm, and 0.73W at 1040 nm were obtained. The slope efficiency was measured to be 82.4% for the 1078 nm laser emission and 57.1% for the 1040 nm laser emission.

J. Kong;定元 汤;C. C. Chan;J. Lu;K. Ueda;H. Yagi;T. Yanagitani

Optics Letters

2007-2-1

We have experimentally demonstrated a high-power self-mode-locked Yb:Y₂O₃ ceramic laser. Without any additional active or passive element in the cavity, self-started cw mode-locking was achieved. The maximum output power was as high as 2.7W with a pulse duration of 1.1 ps. Numerical studies show that the diffraction loss induced by thermal lens aberration, in combination with the Kerr self-focusing effect in the gain medium, results in the mode locking of the laser. To our knowledge, this is the first self-mode-locked ceramic laser.

G. Q. Xie;定元 汤;L. M. Zhao;列加 钱;K. Ueda

Optics Letters

2007-9-15

We demonstrate a 2097nm Q-switched Ho:YAG ceramic laser resonantly pumped by a Tm:YLF laser. The Q-switched pulse energy was 9.6 mJ at a pulse repetition frequency (PRF) of 200 Hz and 10.2 mJ at a PRF of 100 Hz, respectively. The M² factors were measured to be less than 1.1 in both directions.

Lei Wang;春清 高;Mingwei Gao;Yan Li;Fuyong Yue;Jian Zhang;定元 汤

2013

We report on the experimental observation of high peak power stretched-pulse emission in a dispersion-managed (DM) fiber laser with large positive net cavity dispersion. As stretched pulses are normally observed in DM fiber lasers with around zero cavity dispersion, it suggests that the effective cavity dispersion of a DM fiber laser is not a fixed value but varies with the laser operation conditions. Based on numerical simulations we further show that a stretched pulse could indeed be obtained in our laser under the laser operation condition when a high peak power pulse is formed, suggesting that the effective cavity dispersion shifts with the cavity nonlinearity.

X. Wu;定元 汤;L. M. Zhao;H. Zhang

Physical Review A - Atomic, Molecular, and Optical Physics

2009-8-6

The behaviour of light transmitted through an individual subwavelength aperture becomes counterintuitive in the presence of surrounding 'decoration', a phenomenon known as the extraordinary optical transmission. Despite being polarization-sensitive, such an individual nano-aperture, however, often cannot differentiate between the two distinct spin-states of photons because of the loss of photon information on light-aperture interaction. This creates a 'blind-spot' for the aperture with respect to the helicity of chiral light. Here we report the development of a subwavelength aperture embedded with metasurfaces dubbed a 'meta-aperture', which breaks this spin degeneracy. By exploiting the phase-shaping capabilities of metasurfaces, we are able to create specific meta-apertures in which the pair of circularly polarized light spin-states produces opposite transmission spectra over a broad spectral range. The concept incorporating metasurfaces with nano-apertures provides a venue for exploring new physics on spin-aperture interaction and potentially has a broad range of applications in spin-optoelectronics and chiral sensing.

Luping Du;Shan Shan Kou;Eugeniu Balaur;Jasper J. Cadusch;Ann Roberts;Brian Abbey;小聪 袁;定元 汤;Jiao Lin

Nature Communications

2015-12-1

We propose a simple erbium-doped fiber ring laser. It consists of an inverse-Gaussian apodized fiber Bragg grating filter which has two ultra-narrow transmission bands, and an unpumped erbium-doped fiber as a saturable absorber. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength separation of approximately 0.082 nm is achieved. A microwave signal at 10.502 GHz is demonstrated by beating the dual wavelengths at a photodetector.

Bo Lin;Swee Chuan Tjin;Han Zhang;定元 汤;Sheng Liang;Jianzhong Hao;Bo Dong

Optical Fiber Technology

2011-3