A newly grown Ba Ga4Se7 crystal has been synthesized via the Bridgman-Stockbarger technique.This new crystal has advantages of high nonlinear optics（NLO） coefficients,high laser damage thresholds,and wide transparen...A newly grown Ba Ga4Se7 crystal has been synthesized via the Bridgman-Stockbarger technique.This new crystal has advantages of high nonlinear optics（NLO） coefficients,high laser damage thresholds,and wide transparent regions.The Ba Ga4Se7 crystal has bright application prospects as a nonlinear gain medium in mid-infrared and terahertz regions.In this paper,the crystalline structure and synthetic method of the Ba Ga4Se7 crystal are introduced.The refractive indices and absorption coefficients along three dielectric axes between 0.1 THz and 1.0 THz are also obtained.The terahertz difference frequency generation（THz-DFG） characteristics based on the BaG a4Se7 crystal in the frequency range of 0.1 THz to 1.0 THz are analyzed theoretically and the phase-matching conditions are calculated.The application of Ba Ga4Se7 crystals in terahertz wave generation is also discussed.展开更多
High-power terahertz(THz) generation in the frequency range of 0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago, enabling new technological breakthroughs in ...High-power terahertz(THz) generation in the frequency range of 0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago, enabling new technological breakthroughs in spectroscopy, communication, imaging,etc. By using optical(laser) pumping methods with near-or mid-infrared(IR) lasers, flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology. This paper overviews various optically pumped THz sources, including femtosecond laser based ultrafast broadband THz generation, monochromatic widely tunable THz generation, single-mode on-chip THz source from photomixing, and the traditional powerful THz gas lasers. Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well. It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.展开更多
基金supported by the National Basic Research Program of China(973)under Grant No.2015CB755403 and No.2014CB339802National High Technology Research and Development Program(863)under Grant No.2011AA010205+6 种基金National Natural Science Foundation of China under Grant No.61107086No.61172010and No.61471257Natural Science Foundation of Tianjin under Grant No.14JCQNJC02200Science and Technology Support Program of Tianjin under Grant No.14ZCZDGX00030Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20120032110053CAEP THz Science and Technology Foundation under Grant No.CAEPTHZ201304
文摘A newly grown Ba Ga4Se7 crystal has been synthesized via the Bridgman-Stockbarger technique.This new crystal has advantages of high nonlinear optics（NLO） coefficients,high laser damage thresholds,and wide transparent regions.The Ba Ga4Se7 crystal has bright application prospects as a nonlinear gain medium in mid-infrared and terahertz regions.In this paper,the crystalline structure and synthetic method of the Ba Ga4Se7 crystal are introduced.The refractive indices and absorption coefficients along three dielectric axes between 0.1 THz and 1.0 THz are also obtained.The terahertz difference frequency generation（THz-DFG） characteristics based on the BaG a4Se7 crystal in the frequency range of 0.1 THz to 1.0 THz are analyzed theoretically and the phase-matching conditions are calculated.The application of Ba Ga4Se7 crystals in terahertz wave generation is also discussed.
基金supported by the National Basic Research Program of China(Grant No.2014CB339802)the National Natural Science Foundation of China(Grant Nos.61675146,61471257,61505089,61275102&61271066)
文摘High-power terahertz(THz) generation in the frequency range of 0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago, enabling new technological breakthroughs in spectroscopy, communication, imaging,etc. By using optical(laser) pumping methods with near-or mid-infrared(IR) lasers, flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology. This paper overviews various optically pumped THz sources, including femtosecond laser based ultrafast broadband THz generation, monochromatic widely tunable THz generation, single-mode on-chip THz source from photomixing, and the traditional powerful THz gas lasers. Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well. It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.
