A new type of gravitational wave probe with high s

2022-08-02
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Einstein Institute has developed a new type of gravitational wave detector with high sensitivity recently, researchers at Einstein Institute have proposed two new technologies that can further improve the sensitivity of future gravitational wave detectors

a year ago, people first detected gravitational waves directly. Laser experts from Planck Institute of gravitational physics (AEI of Albert Einstein Institute), Leibniz University Hannover branch and Hannover laser center company (lzh) played a major role in this discovery, because the core instrument in the American laser interference gravitational wave observatory used by them has ultra precision laser technology, which can detect weak gravitational wave signals

now, the Max Planck Society has also strengthened the development of the laser system of the third generation gravitational wave detector. Einstein institute cooperates with Hannover laser center and plans to invest 3.75 million euros in research in the next five years Check and repair the research funds for power supply lines, and carry out the development of new laser Zentrum. Hannover Research Center has received more than 3.75 million euros in research in the next five years. Let's learn about the relevant knowledge of changing the testing machine, and carry out research on new lasers and methods to improve their stability

"we have made important breakthroughs," said Professor Benno Willke, who is the leader of the laser development group of Einstein Institute. "Our work is to further study another new type of laser beam used in the interferometric gravitational wave detector. In addition, we have shown how to improve the power stability, that is, the stability of the high-power laser used in the detector. This is an important step in the research of gravitational waves in the future astronomy." this research result was published in the famous scientific journal optical letters, and has been paid attention to

more homogeneous laser beam

the intensity of the gravitational wave detector beams of all laser systems currently used is higher at the center than at the edge. This will lead to a measurement accuracy problem of gravitational wave detector which is not expected to be caused by the fluctuation of mirror surface. This so-called thermal noise can be improved by a more uniform laser intensity distribution

in 2013, the research team demonstrated how to obtain a more uniform high-power laser beam and create the so-called lg33 mode. Now that Andreas Noack has completed his master's thesis, Benno Willke's team is trying to apply these laser beams to future gravitational wave detectors

the first step into the detector is a device called predictive mode cleaner, which optimizes the beam profile and reduces beam jitter. Willke's team found that the new lg33 beam is compatible with the currently used predictive cleaning mode. The researchers also showed how to solve this problem. They have developed a new pre cleaning mode, which is compatible with the lg33 laser mode

"the design of the next generation gravitational wave detector has not been completed yet," Willke said. "Therefore, we are testing different types of lasers, finding as many options as possible with less linear error, and implementing new gravitational wave detectors as possible. With the lg33 laser beam, we have made a big step forward."

improve the stability of laser emission power for the detection of new gravitational waves

all interferometric gravitational wave detectors, such as LIGO, Virgo and geo600, rely on laser systems and need to be saved and processed after experiments. They put forward higher requirements to keep their high output power stable within one year, and their power fluctuations in the time scale are very small. Benno Willke's research team is a world leader in this research field. They have established the laser system geo600 and advanced LIGO. Without such equipment, it is impossible to directly detect gravitational waves for the first time in September 2015

now, Jonas Junker has further improved the existing power stability system in the master's research in Willke's team. A part of the laser beam is removed to realize multiple distribution of detectors, so as to accurately determine the total power. If it changes, the main laser power is corrected accordingly. In their experiments, scientists have expanded the current system. In addition, another photodetector can control and correct the direction of the laser beam

in Einstein Institute, the improved power stabilization scheme has been successfully applied to the 10m prototype interferometer of a 35 watt laser system. The prototype was demonstrated and tested by Hanover researchers for the technology of the third generation detectors, and the quantum mechanical effects were studied in these instruments. The power stability is five times higher than that of other groups. This result is in good agreement with the results of an independent desktop experiment

"the experiment conducted in an optical laboratory isolated from the external environment is completely different from the large-scale experiment of the 10 meter prototype. We found for the first time that it can be transferred from a desktop experiment with excellent stability," Willke said. "We found that these photodiode arrays work as expected, which means that it should also be able to be used in the same multi detector array for advanced LIGO and achieve this high stability."

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