The influence of temperature and input energy on the fluorescence emission cross section of Nd3＋ ：YAG crystal is studied. The stimulated emission cross sections of quasi-three-level systems are determined in a tempe...The influence of temperature and input energy on the fluorescence emission cross section of Nd3＋ ：YAG crystal is studied. The stimulated emission cross sections of quasi-three-level systems are determined in a temperature range from -30 to 60 ℃ and an input energy range from 18 to 75 J. The cross section is found to be decreased when the temperature and the input energy are increased. This is attributed to the thermal broadening mechanism of the emission line. This study is relevant for the development of laser design.展开更多
The thermal effect on the laser transition at 946nm is investigated.The temperature of the cooling system is verified in the range 2-60℃.A Nd:YAG laser crystal is utilized as a gain medium and is pumped by a newly de...The thermal effect on the laser transition at 946nm is investigated.The temperature of the cooling system is verified in the range 2-60℃.A Nd:YAG laser crystal is utilized as a gain medium and is pumped by a newly developed flashlamp.The variable pumping energy is accomplished within the 5-40 d range.The stimulated emission cross section of the 946-nm line is estimated based on the fluorescence spectrum of the Nd:YAG laser.The stimulated emission cross section of the 946-nm line is found to be inversely proportional to the temperature and to the input energy due to the increase of the thermal population at the ground level.展开更多
The purpose of this paper is to compare the performance of two spectrometers that are manufactured from the same company. In this work, heavy metals like lead Pb and copper Cu in the KBr matrix were analyzed using the...The purpose of this paper is to compare the performance of two spectrometers that are manufactured from the same company. In this work, heavy metals like lead Pb and copper Cu in the KBr matrix were analyzed using the laser induced breakdown spectroscopic technique. A Q-switched Nd：YAG laser with 90mJ per pulse operating at the fundamental wavelength of 1064nm and pulse duration of 10 ns was used to generate plasma at the focal region. The important experimental parameters such as the laser energy, integration time, distance between the lens and sample, distance and angle of the optical fiber from the target were optimized. Two spectrometers manufactured by Ocean Optics namely as Maya2000Pro and USB 4000 were employed for anlyzing the spectral lines. The experimental setup and conditions were remained the same for both experiments. The production of spectral lines from each of the interested elements was analyzed and compared with the NIST （National Institute of Standards and Technology） database. The sensitivity, repeatability and limit of detection for each of the systems are discussed in detail.展开更多
We proposed a compact design of an optical biochemical sensor based on the Mach-Zehnder interferometer （MZI）, which was coupled by a ring resonator （RR） as a sensing tool. The sensor sensitivity has been determine...We proposed a compact design of an optical biochemical sensor based on the Mach-Zehnder interferometer （MZI）, which was coupled by a ring resonator （RR） as a sensing tool. The sensor sensitivity has been determined by power difference at the output ports. The sensor enhancement has been optimized by numerically evaluating the geometrical parameters of the MZ! and RR. A great sensor sensitivity depicted by Fano resonance characteristic has been demonstrated as a function of the round trip phase in the range of 4×10^-4 - 4×10^-4, which was changed by the presence of the sample solution in the sensing area. This optimum sensitivity has been obtained for the values of two coupling coefficients of the MZI k1 =k2 =0.5/mm and the coupling coefficient between the MZI arm and RR KR = 0.5/ram. Furthermore, a good profile of sensitivity exchange has been exhibited by inducing the direct current voltage to the coupling region of k R. Finally, the output power transmission of the ring-coupled arm was depicted as a function of tunable k R.展开更多
A Q-switched ytterbium-doped fiber laser （YDFL） is proposed and demonstrated using a newly developed multi-walled carbon nanotubes polyethylene oxide （MWCNTs-PEO） film as a passive saturable absorber （SA）. The s...A Q-switched ytterbium-doped fiber laser （YDFL） is proposed and demonstrated using a newly developed multi-walled carbon nanotubes polyethylene oxide （MWCNTs-PEO） film as a passive saturable absorber （SA）. The saturable absorber is prepared by mixing the MWCNTs homogeneous solution into a dilute PEO polymer solution before it is left to dry at room temperature to produce thin film. Then the film is sandwiched between two FC/PC fiber connectors and integrated into the laser cavity for Q-switching pulse generation. The laser generates a stable pulse operating at wavelength of 1060.2 nm with a threshold pump power of 53.43 mW. The YDFL generates a stable pulse train with repetition rates ranging from 7.92 to 24.27 kHz by varying 980-nm pump power from 53.42 to 65.72 mW. At 59.55-mW pump power, the lowest pulse width and the highest pulse energy are obtained at 12.18 μs and 143.5 n J, respectively.展开更多
基金Project supported by the Higher Education of Malaysia (Grant No. 7126.00H10)the International Development Fund
文摘The influence of temperature and input energy on the fluorescence emission cross section of Nd3＋ ：YAG crystal is studied. The stimulated emission cross sections of quasi-three-level systems are determined in a temperature range from -30 to 60 ℃ and an input energy range from 18 to 75 J. The cross section is found to be decreased when the temperature and the input energy are increased. This is attributed to the thermal broadening mechanism of the emission line. This study is relevant for the development of laser design.
基金Supported by government of Malaysia through MOHE under Grant No 7126.00H10,for Mr Seyed Ebrahim Pourmand to pursue his PhD through IDF program,and RMC.
文摘The thermal effect on the laser transition at 946nm is investigated.The temperature of the cooling system is verified in the range 2-60℃.A Nd:YAG laser crystal is utilized as a gain medium and is pumped by a newly developed flashlamp.The variable pumping energy is accomplished within the 5-40 d range.The stimulated emission cross section of the 946-nm line is estimated based on the fluorescence spectrum of the Nd:YAG laser.The stimulated emission cross section of the 946-nm line is found to be inversely proportional to the temperature and to the input energy due to the increase of the thermal population at the ground level.
文摘The purpose of this paper is to compare the performance of two spectrometers that are manufactured from the same company. In this work, heavy metals like lead Pb and copper Cu in the KBr matrix were analyzed using the laser induced breakdown spectroscopic technique. A Q-switched Nd：YAG laser with 90mJ per pulse operating at the fundamental wavelength of 1064nm and pulse duration of 10 ns was used to generate plasma at the focal region. The important experimental parameters such as the laser energy, integration time, distance between the lens and sample, distance and angle of the optical fiber from the target were optimized. Two spectrometers manufactured by Ocean Optics namely as Maya2000Pro and USB 4000 were employed for anlyzing the spectral lines. The experimental setup and conditions were remained the same for both experiments. The production of spectral lines from each of the interested elements was analyzed and compared with the NIST （National Institute of Standards and Technology） database. The sensitivity, repeatability and limit of detection for each of the systems are discussed in detail.
文摘We proposed a compact design of an optical biochemical sensor based on the Mach-Zehnder interferometer （MZI）, which was coupled by a ring resonator （RR） as a sensing tool. The sensor sensitivity has been determined by power difference at the output ports. The sensor enhancement has been optimized by numerically evaluating the geometrical parameters of the MZ! and RR. A great sensor sensitivity depicted by Fano resonance characteristic has been demonstrated as a function of the round trip phase in the range of 4×10^-4 - 4×10^-4, which was changed by the presence of the sample solution in the sensing area. This optimum sensitivity has been obtained for the values of two coupling coefficients of the MZI k1 =k2 =0.5/mm and the coupling coefficient between the MZI arm and RR KR = 0.5/ram. Furthermore, a good profile of sensitivity exchange has been exhibited by inducing the direct current voltage to the coupling region of k R. Finally, the output power transmission of the ring-coupled arm was depicted as a function of tunable k R.
基金supported by Ministry of Higher Education under ERGS Grant scheme No.ER012-2012A
文摘A Q-switched ytterbium-doped fiber laser （YDFL） is proposed and demonstrated using a newly developed multi-walled carbon nanotubes polyethylene oxide （MWCNTs-PEO） film as a passive saturable absorber （SA）. The saturable absorber is prepared by mixing the MWCNTs homogeneous solution into a dilute PEO polymer solution before it is left to dry at room temperature to produce thin film. Then the film is sandwiched between two FC/PC fiber connectors and integrated into the laser cavity for Q-switching pulse generation. The laser generates a stable pulse operating at wavelength of 1060.2 nm with a threshold pump power of 53.43 mW. The YDFL generates a stable pulse train with repetition rates ranging from 7.92 to 24.27 kHz by varying 980-nm pump power from 53.42 to 65.72 mW. At 59.55-mW pump power, the lowest pulse width and the highest pulse energy are obtained at 12.18 μs and 143.5 n J, respectively.
