Upper-limit on the Advanced Virgo output mode cleaner cavity length noise

Abstract

Abstract. The Advanced Virgo detector uses two monolithic optical cavities at its output port to suppress higher order modes and radio frequency sidebands from the carrier light used for gravitational wave detection. These two cavities in series form the output mode cleaner. We present a measured upper limit on the length noise of these cavities that is consistent with the thermo-refractive noise prediction of 8 × 10 −16 m/Hz 1/2 at 15 Hz. The cavity length is controlled using Peltier cells and piezo-electric actuators to maintain resonance on the incoming light. A length lock precision of 3.5 × 10 −13 m is achieved. These two results are combined to demonstrate that the broadband length noise of the output mode cleaner in the 10-60 Hz band is at least a factor 10 below other expected noise sources in the Advanced Virgo detector design configuration.PACS numbers: 04.80. Nn, 95.55.Ym

A guide to LIGO–Virgo detector noise and extraction of transient gravitational-wave signals

“…See [48] for a detailed presentation on the characterization of transient noise in Advanced LIGO, especially pertaining to the observation of the gravitational-wave signal GW150914. Descriptions of various noise sources for Advanced Virgo in O2 can be found in [84][85][86][87].…”

Calibration of advanced Virgo and reconstruction of the detector strain h(t) during the observing run O3

“…The output beam used to observe the interference fringes is a small fraction of the interferometer output beam extracted before the output mode-cleaner cavity [31]. It is sent onto a photodiode, and the non-linear ΔL reconstruction uses two channels from this photodiode: P DC , that measures the output power components from 0 to 10 kHz, and P AC , that is extracted using digital demodulation at 56 MHz.…”

“…56 MHz RIN noise: the output mode cleaner cavity (OMC) filters out the non TEM00 104 modes of the output laser beam created by optical defaults and misalignments, and the radio frequency sidebands used for interferometer control [31]. In practice, a small fraction of these modes and sidebands is transmitted by the OMC and add phase variations in the dark fringe signal.…”

Calibration of Advanced Virgo and reconstruction of detector strain h(t) during the Observing Run O3

“…56 MHz RIN noise: The Output Mode Cleaner cavity (OMC) filters out the additional modes created by optical defaults, misaligments and radio frequency sidebands used for interferometer control [28]. In practice, a small fraction of these modes is transmitted by the OMC and add phase variations in the dark fringe signal.…”