New optical technology enhances gravitational wave detection capabilities

A team of physicists led by Jonathan Richardson of the University of California Riverside, published in a physicist review letter earlier this month, revealing a new optical technology that sets the detection range of laser interferometers’ gravitational wave astronomical observatory. It shows how it can be expanded. Breaking the way to the Wave Observatory, or Ligo, and the future observatory.

Since 2015, observatory like Ligo has opened new windows in space. Plans for future upgrades to a 4-kilometer Rigo detector and plans for the construction of a space explorer, the next generation of 40-kilometer observatory, will first be the earliest in the history of space. It aims to push the horizon up. The stars have formed. But to recognize that these plans depend on achieving laser power levels above 1 megawatt, far beyond the capabilities of Ligo today.

The research paper reports a breakthrough that allows gravitational wave detectors to reach extreme laser power. This presents a new low-noise, high-resolution adaptive optics approach that can correct the limited distortion of the Ligo main 40 kilogram mirror that occurs with increased laser power due to heating.

Richardson, an assistant professor of physics and astronomy, will explain the findings of his paper in the following Q&A:

What are gravitational waves?

Gravitational waves are a new way to observe the universe. They are predicted by the equation of general theory of relativity. When a giant object accelerates or collides in space, the distortion of the fabric of space-time propagates like ripples in a pond at the speed of light. These distortions are gravitational waves, which carry energy and momentum, just like electromagnetic waves. Currently, there is a lot of information about extreme astrophysical objects like black holes, and the physics of the black holes that create them, and the underlying properties of the space-time that these waves travel to reach us. There is information about the academic field.

How does Ligo work?

The Ligo is one of the largest scientific instruments in the world. It consists of two 4km x 4km long laser interferometers. One of these interferometers is located within Washington. The other is outside Baton Rouge, Louisiana. These sister sites operate in tandem and passively hear space-time distortions that can propagate through the Earth as gravitational waves.

So far, Ligo has seen about 200 events of stellar mass compact objects collide and fuse together. The overwhelming majority were the merger of two black holes, but we’ve also seen the merger of neutron stars. I hope one day we can detect sources that are completely unexpected and unpredictable. Looking at the history of astronomy, whenever we develop an electromagnetic telescope that can observe light of different wavelengths that have never been observed before, the universe is seen literally in new light, almost always discovering a new type of object. I’ve done it. It can be seen in that wavelength band, but not in other bands. I hope the same applies to gravitational waves.

Please tell us about the equipment you developed in a lab with a LIGO application.

My focus at UCR is developing a new type of laser adaptive optics technology to overcome the limitations of very basic physics on how detectors like LIGO can be made sensitive. It’s about doing it. Over the majority of gravitational wave signals that can be seen from the ground, almost all of them are limited in sensitivity by the quantum mechanics used to bounce the mirror due to the quantum properties of the laser beam itself used in interferometers. The equipment we developed in my lab is designed to provide precise optical correction directly to the main mirror of the Rigo interferometer. Our equipment is designed to sit only a few centimeters in front of the reflective surface of these mirrors and project very low noise-corrected infrared rays onto the front of the mirror. This is the first prototype of an entirely new type of approach that uses non-imaging optical principles that have not been used in gravitational wave detection before.

What is Cosmic Explorer?

Cosmic Explorer is the US concept of the next generation gravitational wave observatory after Ligo. This is a 40 x 40km interferometer group, which is 10 times the size of a Ligo. This will be the largest scientific instrument ever built. In design sensitivity, these detectors see the universe at a previous period than when it was believed that the first star formed when the universe was about 0.1% of the current 14 billion years old. It must be. You can see a snapshot of the universe very early on.

Simply put, what does the research paper discuss?

This paper shows that high-precision optical correction is essential to expanding the gravitational wave view of the universe. It shows the potential impact our new technology will have on the next generation of Ligo and even more years. Importantly, this paper shows that this type of technology is necessary and appropriate to enable much higher levels of circulating laser power in LIGO detectors than ever before. This technology and future versions expect to achieve more power with interferometers.

Why is it important to do this research?

This research promises to answer some of the deepest questions in physics and cosmology, including how quickly the universe is expanding, and the true nature of black holes. Currently, there are two contradictory measures in the local expansion rate of the universe, potentially solving gravitational waves. Gravitational waves also provide exquisitely high precision measurements of detailed dynamics around the event horizon of black holes, allowing the classic theory of general relativity and alternative theories to be tested directly.