Simulating a Dual-Recycled Gravitational Wave Interferometer with Realistically Imperfect Optics

Abstract

Abstract.We simulate the performance of a gravitational wave interferometer in the Dual Recycling (DR) configuration, as will be used for systems like Advanced-LIGO. Our grid-based simulation program models complex interferometric detectors with realistic optical deformations (e.g., finescale mirror surface roughness). Broadband and Tuned DR are modeled here; the results are also applied qualitatively to Resonant Sideband Extraction (RSE). Several beneficial properties anticipated for DR detectors are investigated: signal response tuning and narrowbanding, power loss reduction, and the reclamation of lost power as useful light for signal detection. It is shown that these benefits would be limited by large scattering losses in large (multi-kilometer) systems. Furthermore, losses may be resonantly enhanced (particularly for RSE), if the interferometer's modal resonance conditions are not well chosen. We therefore make two principal recommendations for DR/RSE interferometers: the DR/RSE cavity must be modally nondegenerate; and fabricated mirror surfaces and coatings must be as smooth as is practically feasible.

Asymmetry between the sidebands used for detecting gravitational waves in laser interferometric antennas

“…Our analysis has been confirmed by two numerical programs that are widely used for simulations in the LIGO Laboratories. 6,7 In addition to the simple geometrical perturbations, we have analyzed the case of frequency-dependent distortions. The role of the macroscopic and microscopic con- Fig.…”

“…In fact, from Eqs. (7) and (8), we can derive the reflectivities (13) which result in a differential phase, that should be compensated for by tuning…”

Grid-based simulation program for gravitational wave interferometers with realistically imperfect optics

“…The latest versions of our program continue to be used to address important questions raised by the LIGO Project, such as estimating the performance of advanced-LIGO detectors [25,31,57] -i.e., interferometers incorporating Dual Recycling [23], or even Resonant Sideband Extraction [59] -in the presence of optical deformations, and participating in initiatives to set core optical specifications (and to design the control systems) for those advanced detectors [31,63]. Many related issues will undoubtedly arise in the near future, as advanced interferometer configurations (and increasingly better optics) become available, for which this program can be used as a primary modeling tool for LIGO and its collaborating gravitational wave groups.…”

“…This has been achieved through a combination of fast iteration techniques, efficient parameter optimization routines, and procedures designed to carefully choose the initial guesses for laser fields that are computed via relaxation. Lastly, we note that versions of the code are available for both the first-generation LIGO and advanced-LIGO (Dual Recycling [23]) configurations [24,25], though we will focus primarily upon the former in this paper.…”

Effects of mirror aberrations on Laguerre-Gaussian beams in interferometric gravitational-wave detectors

“…Previous work [27] has shown that the presence of a signal recycling cavity can substantially reduce the contrast defect in the case where the resonant mode in the interferometer is TEM 0,0 . The higher order transverse modes are not resonant in the signal recycling cavity and are therefore suppressed.…”