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	A novel bottom-emitting vcsel's one-dimension array (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China 作者: Wang L.; Wang L.; Wang L.; Liu Y.; Liu Y. 收藏 \| 浏览/下载：25/0 \| 提交时间：2013/03/25 A novel 980nm bottom-emitting VCSELs array with high power density and good beam property of Gaussian far-field distribution is reported. This array is composed of 5 symmetrically-arranged elements of 200m 150m and 100m-diameter with the center spacings of 300m and 250m respectively. The maximum power is 880mW at a current of 4A corresponding to lKW/cm2 average optical power density. The differential resistance is 0.09 with a threshold of 0.56A. The novel array is compared with a 300m-aperture-size single device and a 44 2-D array with 50m element aperture size and 250m centre spacing. The three devices have the same lasing area. The conclusion is that the novel array is better in the property of output power threshold current lasing spectra far-field distribution etc. 2008 SPIE.
	High power VCSEL device with periodic gain active region (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China 作者: Zhang Y.; Liu Y.; Liu Y.; Liu Y.; Qin L. 收藏 \| 浏览/下载：31/0 \| 提交时间：2013/03/25 High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400m-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16 were observed with current beyond 4.8A.
	High-power InGaAs/GaAs VCSEL's two-dimension arrays (EI CONFERENCE) 会议论文 OAI收割 ICO20: Lasers and Laser Technologies, August 21, 2005 - August 26, 2005, Changchun, China 作者: Liu Y.; Wang L.-J.; Wang L.-J.; Liu Y.; Liu Y. 收藏 \| 浏览/下载：26/0 \| 提交时间：2013/03/25 Selectively oxidized InGaAs/GaAs vertical -cavity surface-emitting lasers (VCSEL) array at an emission wavelength of 980nm was reported. A 16 elements array with 200m aperture size (250m center spacing) of individual elements shows a CW output power of 1.21 W at room temperature resulting in 1 KW/cm2 average optical power density. The device threshold current is 1.32A The lasing peak wavelength is 981.9 nm the full width at half-maximum is 0.7 nm and the far-field divergence angle is about 17.The characteristics of a single device with a active region diameter of 800m is compared with that of a 2-D array with active region diameter of individual clement of 200m. These two kinds of devices have the same total lasing area. At the same current injection the single device has a higher threshold and a higher output power than the array. The red shift of single device is more obvious than that of the array's.
	High-power InGaAs VCSEL's single devices and 2-D arrays (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Materials and Devices for Optical Communications, November 7, 2005 - November 10, 2005, Shanghai, China 作者: Sun Y.; Wang L.; Wang L.; Wang L.; Liu Y. 收藏 \| 浏览/下载：23/0 \| 提交时间：2013/03/25 We report on bottom-emitting vertical-cavity surface-emitting lasers (VCSEL's) and laser arrays providing high output powers in the 980-nm wavelength regime. Single devices with active diameters of 500 m show high output powers of 1.95 W at room temperature. Its threshold current is 510 mA and the maximum spatially averaged optical power density is 0.93 kW/cm2. A 16 elements array with 200m aperture size (250m center spacing) of individual elements shows a CW output power of 1.21 W at room temperature resulting in a average optical power density of 1KW/cm2. The threshold current of the array is 1.32A and the lasing peak wavelength is 981.9 nm. The distinction of emission spectrums between the single device and the array is discussed.
	Gyromagnetic factor of Cr4+ ions in forsterite 期刊论文 OAI收割 Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 2005, 卷号: 61, 期号: 8, 页码: 1905-1908 W. C. Zheng; X. X. Wu; Y. J. Fan 收藏 \| 浏览/下载：28/0 \| 提交时间：2012/04/14 electron paramagnetic resonance charge-transfer mechanism crystal and ligand-field theory Cr4+ Mg2SiO4 electron-paramagnetic-resonance chromium-doped forsterite atomic screening constants scf functions lasing center spectroscopy semiconductors parameters excitation cr-4+