The Shenguang-II high power laser facility (SG-II facility), consisting of an 8-beam laser system and a SG-II multifunctional high-energy laser system (9th beam), is currently the only high power Nd-glass solid laser facility with an active probe light in China. In a nanosecond, it can hit a target with a laser beam that has a peak power several times that of the total global power grid, thus forming a high-temperature plasma and subsequently causing fusion. It can greatly facilitate experimentation and research on laser-plasma interactions and inertial confinement fusion. The SG-II facility is of great importance in advancing national strategic high-tech innovation, basic science, and innovation at the frontiers of interdisciplinary science.
In 1986, the National Laboratory on High Power Laser and Physics established the Shenguang-I high power laser facility (SG-I facility). The SG-I facility became an important experiment platform for conducting worldwide cutting-edge research and was of great importance in science and technology research at the frontiers of current knowledge, as well as national economic development.
In 1994, the SG-I facility was retired after 8 years of continuous service. In May 1994, research and development of the Shenguang-II high power laser device (8-beam system) began. Independently developed advanced laser technology was used in the new 8-beam system. In 2000, the 8-beam system was completed and began operation. The total output power of the 8-beam system is 6 kJ/1 ns, and the system has the capability to double or triple the laser frequency. It has become and will continue to be an important platform for basic science and technology research such as inertial confinement fusion (ICF), X-ray laser research and development, and high energy density physics. The 8-beam system passed the technical inspection and evaluation conducted jointly by the Chinese Academy of Sciences and the China Academy of Engineering Physics in 2001. It also won first prize in the Shanghai Science and Technology Progress Award Competition in 2002, first place from the Academy Award for Outstanding Technology Achievement in February 2004, and the second prize awarded by the National Award for Science and Technology Progress in 2005.
In late 2002, the Lab began to develop a multifunction high-energy laser system (9th beam) for the SG-II facility. The 9th beam was completed and put into operation in 2005. The output power of the 9th beam can reach 5.2 kJ/3 ns at its fundamental frequency, with a conversion efficiency of frequency doubling and tripling higher than 60%. It can produce a laser beam that has properties different from the 8 beams produced by the SG-II device, such as higher output energy and different pulse width. As a probe light, it can serve as an active diagnostic tool for physics experiments, allowing researchers to comprehensively and accurately understand the physical phenomena and to quantitatively understand the physical processes and physical laws related to plasma. Meanwhile, the 9th beam also provides an important higher energy drive laser for related physics experiments, and provides the amplification link, a necessary requirement for the development of a picosecond petawatt laser system. In 2013, this laser system was awarded the second prize of the National Award for Science and Technology Progress.
The completion of the 9th beam not only fulfilled China’s need for facilities to perform inertial confinement fusion research, but also greatly enhanced China’s development of high power laser technology. By developing this laser system, useful experience relevant to the future development and construction of larger high power laser devices in China was obtained.
Since 2000, the SG-II facility has performed more than 6900 shots on scores of complicated physical targets and target types with a 90% annual success rate in recent years. Compared to laser facilities of similar scale, the output energy and power, beam quality, and stability and reliability of the SG-II are now at least equal to the level of advanced overseas facilities. Some technical specifications of the SG-II are even better than those in overseas facilities. This is a great achievement in the history of China’s development of laser driver technology. In 2011, a paper entitled “Successful Simulation of the Top Ring X-ray Source and Reconnection Jets in Solar Flare Using High Power Laser” which described experiments conducted using the SG-II was selected as one of the “2011 Top Ten Advances in Science and Technology of China”.
The development and operation of the SG-II facility has led to the development of a number of element techniques and components, advanced the construction and development of China’s high power laser support systems, and facilitated progress in optical material technology in China, such as nonlinear crystals, large aperture optical components processing, and techniques using Xenon light and film. It also has great social and economic benefits. Currently, neodymium glass laser elements have been exported to Russia, Europe, Israel, South Korea and other countries. Great advances have been made in large caliber nonlinear crystal growth and processing coating technology, breaking the high-tech embargo on China by the US. The domestic large aperture optical components processing industry has grown in both size and manufacturing capability, which has greatly improved the technical support to China’s aerospace, aviation, and national defense industries.
In 2014, the Lab finished debugging the integrated laser driver upgrade unit (8-beam output specifications: 40 kJ/3 ns/1 ω, 24 kJ/3 ns/3 ω) and began performing physics experiments in 2015[It is now 2016, so should this date be changed? Or, do you mean “began performing physics experiments in 2015”?]. Combined with the existing SG-II facility, the Lab will have increased power to support major national projects and will become an important platform for laser driver development and nuclear physics research.
By then, the SG-II facility will have more power to support cutting edge basic science research and will be open to the outside world, becoming a venue for international cooperation and academic exchange. With the facility’s gradual increase in its efforts to enhance international cooperation, it now has a strong international influence and the capability to export technology such as high power laser technology and element techniques. Through continued international cooperation, the SG-II facility will become China’s high power laser technology international export demonstration base, laying a foundation for subsequent extensive international participation in the high power laser field.