Compressed Laser Suppresses Interference

In order to solve the laser quantum noise interference, the LIGO experimental group cooperated with the German GEO600 gravitational wave detector project team to use compressed light technology to weaken the quantum noise. Now these compressed light technologies have been officially used in the GEO600 interferometer, and a preliminary trial has been conducted in the LIGO interferometer. The principle is to use the loopholes in the laws of quantum mechanics to reduce one characteristic fluctuation of light by adding one characteristic fluctuation of light.

Although the sensitivity of GEO600 is not as good as LIGO, many of the core technologies used by LIGO are proposed by scientists of the GEO600 team and completed the test at GEO600. GEO600 project scientists proposed that reducing the uncertainty of laser pointer displacement through compressed light technology can improve the accuracy of gravitational wave detection in high-frequency bands, while reducing laser momentum fluctuations through compressed light technology can improve the sensitivity of detecting gravitational waves in low-frequency bands .

5000mW Laser Pointer 5W 532nm Green Star

However, the current compressed light technology can only reduce the laser displacement fluctuation or the laser momentum fluctuation, and cannot reduce the two quantum noise effects at the same time. LIGO hopes to use a technology called “filter cavity” to achieve simultaneous compression of the quantum noise of the two lasers within 5 years to improve LIGO’s sensitivity to full-range detection of gravitational waves.

The latest results published in “Nature” magazine were completed by Eugene Pozick, a physicist at the Niels Pol Institute at the University of Copenhagen in Denmark. They let the laser first use a gaseous metal cesium atom cloud to apply a force in the opposite direction to the red laser pointer before hitting the target, completely “offsetting” the laser’s momentum fluctuations, thereby reducing the uncertainty caused by quantum effects.34 %.

The Pozick team has begun cooperation with Moscow University and the Russian Quantum Center to further improve this technology. Researchers at the Max Planck Institute of Gravity Wave Physics and LIGO are also discussing cooperation with the Pozick team.

Although this new technology has not yet been verified in gravitational wave detection, Nagos Mawawana, a member of the LIGO project team and a physicist at the Massachusetts Institute of Technology (MIT), believes that the preliminary statistical results show that the technology is very Has potential. Pozick said that after another 5 to 10 years of development, the technology may double the sensitivity of the gravitational wave detector.