L. Xue, You Wang, Wei Zhang, H. Cai, Hongyuan Wang, Juhong Han, G. An
A theoretical procedure has been developed for evaluation of the diffraction efficiency of a Reflecting Volume-Bragg-Grating (RVBG) in accordance with Kogelnik’s theory. The diffraction features have been investigated for the different grating thicknesses, refractive index modulation, and grating spatial frequencies, respectively. The linewidths of a diffracted light and the effective diffraction efficiency have been studied while a certain linewidth in spectrum of an incident LD beam is taken into account in the calculation. The results are thought to be useful in the applications of single-longitudinal-mode (SLM) lasers and linewidth narrowing by means of RVBGs.
{"title":"Theoretical investigation of diffraction features of a planar wave using a Reflecting Volume-Bragg-Grating (RVBG)","authors":"L. Xue, You Wang, Wei Zhang, H. Cai, Hongyuan Wang, Juhong Han, G. An","doi":"10.1117/12.2071670","DOIUrl":"https://doi.org/10.1117/12.2071670","url":null,"abstract":"A theoretical procedure has been developed for evaluation of the diffraction efficiency of a Reflecting Volume-Bragg-Grating (RVBG) in accordance with Kogelnik’s theory. The diffraction features have been investigated for the different grating thicknesses, refractive index modulation, and grating spatial frequencies, respectively. The linewidths of a diffracted light and the effective diffraction efficiency have been studied while a certain linewidth in spectrum of an incident LD beam is taken into account in the calculation. The results are thought to be useful in the applications of single-longitudinal-mode (SLM) lasers and linewidth narrowing by means of RVBGs.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116235589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei Wang, Yi Liu, Yi Chen, L. Xia, Jinshui Shi, Jianjun Deng
A kind of laser diode with high power and short duration is described in this paper. The laser diode is used for triggering gallium arsenide photoconductive semiconductor switch (GaAs PCSS) in the experiment. The driver of the laser diode is based on RF MOSFET and it provides an ultra-fast pulse current, which has the rise-time, FWHM and peak current are 4ns, 17ns and 130A, respectively. The characteristics of the laser diode have been researched, including laser pulse waveform, optical field distribution, and limiting drive current. Using a combination of two laser diodes, the PCSS has a better performance than being triggered by single laser diode in the experiment.
{"title":"Research on high-power laser diode used for triggering photoconductive semiconductor switch","authors":"Wei Wang, Yi Liu, Yi Chen, L. Xia, Jinshui Shi, Jianjun Deng","doi":"10.1117/12.2065240","DOIUrl":"https://doi.org/10.1117/12.2065240","url":null,"abstract":"A kind of laser diode with high power and short duration is described in this paper. The laser diode is used for triggering gallium arsenide photoconductive semiconductor switch (GaAs PCSS) in the experiment. The driver of the laser diode is based on RF MOSFET and it provides an ultra-fast pulse current, which has the rise-time, FWHM and peak current are 4ns, 17ns and 130A, respectively. The characteristics of the laser diode have been researched, including laser pulse waveform, optical field distribution, and limiting drive current. Using a combination of two laser diodes, the PCSS has a better performance than being triggered by single laser diode in the experiment.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116573923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tenglong Li, Juan Wu, Yinghong Sun, Yanshan Wang, Yi Ma
In order to ensure the high power all-fiber laser reliability and excellent beam quality, it is necessary to strip the unwanted cladding light. The common method for stripping cladding light is to recoat the double cladding fiber with a high index gel, but localized heating and low thermal conductivity of the recoating gel are the prime factors limiting the power-handling capability of the cladding power stripper(CPS). An improved fabrication technique to manufacture the CPS is presented. Light stripping section of the fiber is fused with a transparent quartz tube, by applying different amount of etchant along the quartz tube, frosted surface is created and uniformly removal of the cladding light is achieved. The quartz tube is joined to water-cooled thermal enclosure tightly without the gel to avoid heat aggregation. The power-handling capability of the device is tested under 200W of cladding light, and attenuation of 20 dB is achieved.
{"title":"An improved method for stripping cladding light in high power fiber lasers","authors":"Tenglong Li, Juan Wu, Yinghong Sun, Yanshan Wang, Yi Ma","doi":"10.1117/12.2065357","DOIUrl":"https://doi.org/10.1117/12.2065357","url":null,"abstract":"In order to ensure the high power all-fiber laser reliability and excellent beam quality, it is necessary to strip the unwanted cladding light. The common method for stripping cladding light is to recoat the double cladding fiber with a high index gel, but localized heating and low thermal conductivity of the recoating gel are the prime factors limiting the power-handling capability of the cladding power stripper(CPS). An improved fabrication technique to manufacture the CPS is presented. Light stripping section of the fiber is fused with a transparent quartz tube, by applying different amount of etchant along the quartz tube, frosted surface is created and uniformly removal of the cladding light is achieved. The quartz tube is joined to water-cooled thermal enclosure tightly without the gel to avoid heat aggregation. The power-handling capability of the device is tested under 200W of cladding light, and attenuation of 20 dB is achieved.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122303851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. P. Xu, R. Zhang, X. Tian, D. Zhou, N. Zhu, J. Wang, M. Li, D. Hu, X. M. Zhang
FM-to-AM modulations are harmful to output characteristics of large-scale laser facility. In SG-III laser facility, some key techniques have been employed to suppress FM-to-AM modulations. Firstly, phase modulator was arranged at the end of fiber laser injection system to avoid GVD and PMD in the SM fiber system. Secondly, a fiber-based polarization rotated filter was proposed to suppress FM-to-AM modulations independently on each beam. Finally, less wave plates were employed and liquid crystal modulators were coated for decreasing weak etalon effect in preamplifier system. The results indicated that it can reduce the modulation depth less than 10% at a modulation frequency of 2.488GHz in SG-III laser facility.
fm - am调制对大型激光设备的输出特性是有害的。在SG-III型激光设备中，采用了一些关键技术来抑制fm - am调制。首先，在光纤激光注入系统末端设置相位调制器，避免了SM光纤系统中的GVD和PMD;其次，提出了一种光纤偏振旋转滤波器，用于抑制各波束上的fm - am调制。最后，通过减少波片的使用和涂覆液晶调制器来减小前置放大器系统的弱标准子效应。结果表明，在SG-III激光设备中，在2.488GHz的调制频率下，它可以使调制深度降低10%以下。
{"title":"Progress on the suppression of FM-to-AM modulations in SG-III laser facility","authors":"D. P. Xu, R. Zhang, X. Tian, D. Zhou, N. Zhu, J. Wang, M. Li, D. Hu, X. M. Zhang","doi":"10.1117/12.2065284","DOIUrl":"https://doi.org/10.1117/12.2065284","url":null,"abstract":"FM-to-AM modulations are harmful to output characteristics of large-scale laser facility. In SG-III laser facility, some key techniques have been employed to suppress FM-to-AM modulations. Firstly, phase modulator was arranged at the end of fiber laser injection system to avoid GVD and PMD in the SM fiber system. Secondly, a fiber-based polarization rotated filter was proposed to suppress FM-to-AM modulations independently on each beam. Finally, less wave plates were employed and liquid crystal modulators were coated for decreasing weak etalon effect in preamplifier system. The results indicated that it can reduce the modulation depth less than 10% at a modulation frequency of 2.488GHz in SG-III laser facility.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123001904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A laser-diode-pumped master oscillator and power amplifier was developed with high efficiency, high average power and high beam quality. The oscillator is an injection-seeding, fiber coupled diode-end-pumped E-O Q-switched Nd:YAG laser, producing single frequency pulse laser output with pulse energy of 8mJ and pulse width of 11ns at a pulse repetition rate of 1KHz，The 1KHz was divided into four chains with frequency of 250Hz, through E-O modulation technology, The power amplifier utilizes conductively-cooling Nd:YAG zigzag slab with two sides’ pump architecture at bounce point. Pulse energy of more than 800mJ with pulse widths of 12.6ns was obtained at repetition rate of 250Hz in every amplifier chain, the frequency-doubled pulse energy of 360mJ when KTP crystal was used was obtained at a repetition of 250Hz.
{"title":"1KHz high average power single-frequency Nd:YAG laser","authors":"Xiaolei Zhu, Xiuhua Ma, Shiguang Li, Weibiao Chen","doi":"10.1117/12.2070591","DOIUrl":"https://doi.org/10.1117/12.2070591","url":null,"abstract":"A laser-diode-pumped master oscillator and power amplifier was developed with high efficiency, high average power and high beam quality. The oscillator is an injection-seeding, fiber coupled diode-end-pumped E-O Q-switched Nd:YAG laser, producing single frequency pulse laser output with pulse energy of 8mJ and pulse width of 11ns at a pulse repetition rate of 1KHz，The 1KHz was divided into four chains with frequency of 250Hz, through E-O modulation technology, The power amplifier utilizes conductively-cooling Nd:YAG zigzag slab with two sides’ pump architecture at bounce point. Pulse energy of more than 800mJ with pulse widths of 12.6ns was obtained at repetition rate of 250Hz in every amplifier chain, the frequency-doubled pulse energy of 360mJ when KTP crystal was used was obtained at a repetition of 250Hz.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129276912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meng Wang, Qiubo Fu, Yao Wang, Wenzhi Qin, Bi He, Ming Jiang
A laser-driven mini-flyer priming system has been a primary focus for research into advanced initiators in recent years. Due to the low transmission rates and efficieny in the utilization of lasers, it is difficult to apply such a system in practice. Improving the flyer structure’s technology is a key to increasing energy efficiency. We calculate and design the thickness of each layers in the composite flyer plates, then the composite flyers with different parameters are prepared using magnetron sputtering. Taking advantage of a photonic doppler velocimetry (PDV) high-speed testing system, the accelerating processes of flyers with different parameters are analyzed. An experimental comparison is made on HNS-IV donation between laser-driven single-layer aluminium flyer and composite flyer
{"title":"Investigation into the initiation of hexanitrostilbene by laser-driven composite flyer plates","authors":"Meng Wang, Qiubo Fu, Yao Wang, Wenzhi Qin, Bi He, Ming Jiang","doi":"10.1117/12.2065489","DOIUrl":"https://doi.org/10.1117/12.2065489","url":null,"abstract":"A laser-driven mini-flyer priming system has been a primary focus for research into advanced initiators in recent years. Due to the low transmission rates and efficieny in the utilization of lasers, it is difficult to apply such a system in practice. Improving the flyer structure’s technology is a key to increasing energy efficiency. We calculate and design the thickness of each layers in the composite flyer plates, then the composite flyers with different parameters are prepared using magnetron sputtering. Taking advantage of a photonic doppler velocimetry (PDV) high-speed testing system, the accelerating processes of flyers with different parameters are analyzed. An experimental comparison is made on HNS-IV donation between laser-driven single-layer aluminium flyer and composite flyer","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"9255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130662527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In high power laser systems, crystal defects introduced by manufacturing have significant impact on quality of light beams; finally affect the output status of high power laser system. The phase retrieval algorithm can precisely measure the crystal defects, such as the residual periodic perturbations in a relatively large area and the relatively small point defects, with the resolution of micrometer magnitude. At the same time, the multiple near-focus intensity measurements algorithm used here can retrieve the morphology of focal spot, which is modulated by the defects and cannot be directly measured due to its high power. In addition, the algorithm has been improved in order to use less measurement planes and less iteration times to complete retrieval.
{"title":"Measurement of crystal defects using phase retrieval technique","authors":"Yudong Yao, Junyong Zhang, Yanli Zhang, Jianqiang Zhu","doi":"10.1117/12.2071246","DOIUrl":"https://doi.org/10.1117/12.2071246","url":null,"abstract":"In high power laser systems, crystal defects introduced by manufacturing have significant impact on quality of light beams; finally affect the output status of high power laser system. The phase retrieval algorithm can precisely measure the crystal defects, such as the residual periodic perturbations in a relatively large area and the relatively small point defects, with the resolution of micrometer magnitude. At the same time, the multiple near-focus intensity measurements algorithm used here can retrieve the morphology of focal spot, which is modulated by the defects and cannot be directly measured due to its high power. In addition, the algorithm has been improved in order to use less measurement planes and less iteration times to complete retrieval.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121195969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Double fast steering mirror (FSM) are made of a fast steering mirror driven by piezoelectric actuator and a fast steering mirror by voice coin motor, which provides not only high control bandwidth and high resolution but also a wide range of angle for the tracking control system. A classical control system of double fast steering mirror is that each CCD sensor provides line of sight error to control relevant FSM respectively, resulting in complexity and weakening optical energy. The proposed system works by depending on single CCD sensor, which implies that it is crucial to decouple the control double fast steering mirror .An unload technique is designed to solve this problem .The FSM driven by piezoelectric actuator is driven using line of sight from CCD, while the other FSM is followed it. Error attenuation transfer function is modeled and used to analyze stabilization and performance of the control system, which is optimal only if the control bandwidth of FSM driven by piezoelectric actuator is ten times more than that of the FSM driven by the voice coin motor. The experimental results are in great accordance with theoretical analysis.
{"title":"Unload control of double fast steering mirrors of the control system","authors":"T. Tang, Y. Tan, G. Ren","doi":"10.1117/12.2064900","DOIUrl":"https://doi.org/10.1117/12.2064900","url":null,"abstract":"Double fast steering mirror (FSM) are made of a fast steering mirror driven by piezoelectric actuator and a fast steering mirror by voice coin motor, which provides not only high control bandwidth and high resolution but also a wide range of angle for the tracking control system. A classical control system of double fast steering mirror is that each CCD sensor provides line of sight error to control relevant FSM respectively, resulting in complexity and weakening optical energy. The proposed system works by depending on single CCD sensor, which implies that it is crucial to decouple the control double fast steering mirror .An unload technique is designed to solve this problem .The FSM driven by piezoelectric actuator is driven using line of sight from CCD, while the other FSM is followed it. Error attenuation transfer function is modeled and used to analyze stabilization and performance of the control system, which is optimal only if the control bandwidth of FSM driven by piezoelectric actuator is ten times more than that of the FSM driven by the voice coin motor. The experimental results are in great accordance with theoretical analysis.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116292043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The single-frequency two-level (SFTL) generation model was applied to predict the power extraction efficiency in electrically driven oxygen-iodine laser (EOIL). The analysis of the calculated and published experimental data showed that power extraction from the cw EOIL is limited by the rate of energy transfer from singlet oxygen molecules O2(1Δ) to iodine atoms I(2P3/2) and about half of the produced singlet oxygen molecules were carried out from the resonator. To increase power extraction efficiency it will be necessary to substantially extend concentrations of singlet oxygen molecules and iodine atoms in the active medium of EOIL.
{"title":"Features of power extraction in EOIL","authors":"A. V. Mezhenin, V. Azyazov","doi":"10.1117/12.2070248","DOIUrl":"https://doi.org/10.1117/12.2070248","url":null,"abstract":"The single-frequency two-level (SFTL) generation model was applied to predict the power extraction efficiency in electrically driven oxygen-iodine laser (EOIL). The analysis of the calculated and published experimental data showed that power extraction from the cw EOIL is limited by the rate of energy transfer from singlet oxygen molecules O2(1Δ) to iodine atoms I(2P3/2) and about half of the produced singlet oxygen molecules were carried out from the resonator. To increase power extraction efficiency it will be necessary to substantially extend concentrations of singlet oxygen molecules and iodine atoms in the active medium of EOIL.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114021079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A compact diode side-pumped conductively cooled 1047 nm Nd:YLF slab laser with high energy and short pulse width is developed. Through ray tracing method, we design a home-made pump module to homogenize the pump intensity. Based on the Possion equation, a thermal conduct model of side-pump laser is established. The temperature distribution in laser crystal is obtained, and the thermal lens is caculated. With the absorbed pump energy of 818 mJ, the maximum output energy of 228 mJ is achieved in free-running mode. At a repetition rate of 50 Hz, 160 mJ, 9 ns 1047 nm infrared light is obtained under the maximum absorbed pump energy, and the slope efficiency is 27.8%.
{"title":"160mJ and 9ns electro-optics Q-switched conductively cooled 1047nm Nd:YLF laser","authors":"Qi Yang, Jian Ma, Tingting Lu, Xiuhua Ma, Xiaolei Zhu","doi":"10.1117/12.2064316","DOIUrl":"https://doi.org/10.1117/12.2064316","url":null,"abstract":"A compact diode side-pumped conductively cooled 1047 nm Nd:YLF slab laser with high energy and short pulse width is developed. Through ray tracing method, we design a home-made pump module to homogenize the pump intensity. Based on the Possion equation, a thermal conduct model of side-pump laser is established. The temperature distribution in laser crystal is obtained, and the thermal lens is caculated. With the absorbed pump energy of 818 mJ, the maximum output energy of 228 mJ is achieved in free-running mode. At a repetition rate of 50 Hz, 160 mJ, 9 ns 1047 nm infrared light is obtained under the maximum absorbed pump energy, and the slope efficiency is 27.8%.","PeriodicalId":293926,"journal":{"name":"International Symposium on High Power Laser Systems and Applications","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131389668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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