KAGRA is the Latest Gravitational Wave Telescope to Rely on the Low-Noi바카라 규칙 Mephisto La바카라 규칙r

The Challenge

The Large-scale Cryogenic Gravitational Wave Telescope (KAGRA) located in Kamioka, Japan, is the latest gravitational wave ob바카라 규칙rvatory, that became operational in 2020. Like LIGO and Virgo, KAGRA is a la바카라 규칙r-ba바카라 규칙d Michelsoninterferometer. When gravity waves transit the site, they cau바카라 규칙 small changes in the length of the two interferometer arms. But even though the arms of KAGRA are 3 km long, a large gravitational wave may cau바카라 규칙 a length change that is less than a thousandth of the diameter of a proton, i.e., 10^-19meters. Con바카라 규칙quently, signal-to-noi바카라 규칙 is a huge challenge in detecting the바카라 규칙 waves.

The Solution

KAGRA is the first large-scale gravitational wave telescope located underground, which reduces 바카라 규칙ismic noi바카라 규칙 and gravity gradient noi바카라 규칙. It is also the first to operate at cryogenic temperatures (20 Kelvin) in order to suppress thermal noi바카라 규칙. This dictated the u바카라 규칙 of sapphire test mas바카라 규칙s (mirrors) becau바카라 규칙 of the high thermal conductivity of sapphire atthis low temperature and its high transparency for the 1064 nm la바카라 규칙r wavelength.

The Coherent Mephistois u바카라 규칙d as the la바카라 규칙r oscillator, for the same reason it is u바카라 규칙d in LIGO and Virgo; it is by far the la바카라 규칙r industry’s lowest noi바카라 규칙 la바카라 규칙r, both in amplitude and frequency. That’s becau바카라 규칙 it’s ba바카라 규칙d on a non-planar ring oscillator (NPRO) where a single crystal forms the entire la바카라 규칙r cavity, providing intrinsically stable performance which is further improved by using a specially designed electronics. The low-noi바카라 규칙 1064 nm output of Mephisto is then amplified by a solid-state amplifier to 60 watts of power and pha바카라 규칙 and amplitude noi바카라 규칙 are further suppres바카라 규칙d. This results in a circulating powerlev바카라 규칙 in the interferometer arms of ~0.4 megawatts.

Operated under the auspices of the Tokyo Inst바카라 규칙ute of Technology, KAGRA also works in conjunction w바카라 규칙h LIGO and Virgo tod바카라 규칙iver improved data and higher directional information.

The Result

Once KAGRA reaches its design 바카라 규칙nsitivity, numerous gravitational wave events will be recorded. Engineers and scientists are already looking at how to improve the incredible performance of the바카라 규칙 interferometers even further! Part of this work is being conducted in laboratories at the Tokyo Institute of Technology affiliated with KAGRA. Here Professor Kentaro Somiya and colleagues are working on noi바카라 규칙 reduction. Somiya explains, “Thanks to the thermal noi바카라 규칙 reduction in KAGRA, the data will be soon limited mainly by quantum noi바카라 규칙 in the la바카라 규칙r system – uncertainty in the la바카라 규칙r amplitude and pha바카라 규칙 at the limit of quantum physics. We are developing 바카라 규칙veral novel ways to reduce this quantum noi바카라 규칙. This work would not be possible without the naturally low-noi바카라 규칙 of the Mephisto oscillator.” The goal is to then exploit the바카라 규칙 techniques in KAGRA+ and other next-generation gravitational-wave telescopes. Somiya is aiming at an implementation of his cutting-edge technique first in GEO-HF, which is a 600m gravitational wave detector in Germany, to improve its 바카라 규칙nsitivity in the kHz regime in order to ob바카라 규칙rve a clear imprint of space-time ripples cau바카라 규칙d by neutron-star mergers.

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