Abstract
After the first direct detections of gravitational waves, Advanced LIGO
aims to increase its detection rate during the upcoming science runs
through a series of detector improvements, including increased optical
power. Higher circulating power increases the likelihood for three-mode
parametric instabilities (PIs), in which mechanical modes of the mirrors
scatter light into higher-order optical modes in the cavity and the
resulting optical modes reinforce the mechanical modes via radiation
pressure. Currently, LIGO uses two PI mitigation methods: thermal tuning
to change the cavity g-factor and effectively decrease the frequency
overlap between mechanical and optical modes, and active damping of
mechanical modes with electrostatic actuation. While the combined
methods provide stability at the current operating power, there is
evidence that these will be insufficient for the next planned power
increase; future suppression methods including acoustic mode dampers and
dynamic g-factor modulation are discussed.
Original language | English |
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Journal | Bulletin of the American Physical Society |
Volume | 62 |
Issue number | 1 |
Publication status | Published - 1 Jan 2017 |
Event | American Physical Society April Meeting 2017 - Washington DC, United States Duration: 28 Jan 2017 → 31 Jan 2017 |