"People who buy gemstones are often troubled by the difficulty in distinguishing the true and false gems. A shot with a femtosecond laser probe can quickly find out the true and false ones. This process is not only fast, but the damage to the gems can be ignored. "On May 29, Professor Lu Jingqi of the School of Science of Wuhan University of Technology introduced the magical femtosecond laser probe to a reporter from Science and Technology Daily.
Recently, leading his scientific research team, Lu Jingqi just recently completed a study-- using nanosecond, femtosecond and dual-pulse laser induced breakdown spectroscopy technology (commonly known as laser probe) to analyze the composition and calorific value of 18 sets of standard coal samples.
This research result has been published online recently in "Laser and Optoelectronics Progress". Lu Jingqi lamented that femtosecond laser probes have a lot to do in the field of online rapid detection in the future.
Lu Jingqi's scientific research team is conducting experimental tests
"Simply put, it is to hit the sample with a laser to excite the plasma. Then, by measuring the spectrum of the plasma, to obtain the element composition and content in the sample. This technology is laser induced breakdown spectroscopy." Lu Jingqi says, "Everyone vividly calls it a 'laser probe'”.
Laser probe is an emerging spectrum analysis technology, which has the advantages of convenient detection, high speed, simple sample preparation, and real-time online detection of multiple elements. In the past ten years, the application research of laser probe has been continuously expanded in many fields such as petrochemical industry, environmental monitoring, biomedicine, food safety, mineral exploration, cultural relics and archaeology.
In 2017, Lu Jingqi started to lead the team to use laser probes for rapid detection of coal quality.
Thermal power plants use coal as fuel. However, the quality of coal determines the efficiency of combustion and the degree of pollution emissions. Therefore, thermal power plants need to adjust boiler parameters according to the quality of coal to improve combustion efficiency and achieve the effect of energy saving and emission reduction. Lu Jingqi introduced that in order to achieve online detection, before the laser probe came out, the power plant had used neutron activation technology, which used neutron radiation source to emit neutrons to excite gamma rays to detect the elements and content in coal. However, because the neutron source is a radioactive material, it needs to be managed by a specialized agency, and the equipment and maintenance costs are high, and companies are often unwilling to use it.
They developed a nanosecond laser probe, which has been used for rapid detection of coal quality, and the results can be obtained in just a few minutes. Lu Jingqi said that nanosecond laser probes are now a mature technology, and the core equipment, nanosecond lasers, is getting cheaper and cheaper, and the import is only about 200,000 yuan.
"The latest research results are comparative studies of nanosecond, femtosecond, and dual-pulse laser probes. Nanosecond, picosecond, and femtosecond pulse times are all very short. Nanoseconds are on the order of 10-9. Femtoseconds are extremely fast, on the order of 10-15. The excitation is over before the various thermal effects are up. This ultra-short time enables the femtosecond laser probe to avoid matrix effects and fractionation effects." Lu Jingqi said, “From the principle point of view, the femtosecond laser probe should be more accurate in quantification, faster in measurement and cause less damage to the sample”.
However, due to the high price and large size of foreign femtosecond lasers, Lu Jingqi's idea of developing online detection of femtosecond laser probes has never been realized. In 2018, Lu Jingqi knew by chance that the small femtosecond laser independently developed by Wuhan Hongtuo New Technology Co., Ltd. had made a breakthrough. Lu Jingqi immediately cooperated with the Wuhan Hongtuo femtosecond laser research and development team to develop a femtosecond that can be used for online coal detection. After the calorific value quantitative analysis of 18 standard coal samples with different calorific values, it was proved that the femtosecond laser probe has smaller continuous background noise than the nanosecond laser probe, and the relative standard deviation of the single-shot pulse spectrum intensity is smaller. This means higher stability and precision and better repeatability.
Lu Jingqi has been committed to the research and development of laser technology and laser applications. He has done research and development of bioimaging products in multinational companies for more than 6 years, and has accumulated rich experience in the application of laser technology and the design of precision optical instruments. Lu Jingqi also uses femtosecond laser probes in soil detection experiments to analyze heavy metal pollution in the soil. He said that there are many fields of application, such as the analysis of the mineral composition of oil wells, and the detection of water resources and air pollution. The country now has a particularly large demand for soil monitoring, and it is troublesome to send all soil samples to the laboratory for testing. Lu Jingqi imagines that in the future, a set of vehicle-mounted systems can be used to achieve mobile testing.
"This is an industry with great potential, and it is also a technological highland that all countries are seizing." Lu Jingqi is very optimistic about femtosecond laser probe technology. He told a reporter from Science and Technology Daily that with the innovation and breakthrough of China's independent femtosecond laser represented by Wuhan Hongtuo, prices will be greatly reduced, and the popularity of femtosecond laser probes is just around the corner. He hopes that the domestic industry, academia and research cluster innovation will accelerate the application of femtosecond laser probes in various fields so as to build China's independent leading femtosecond laser probe industry.
