Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
复制标题
通过修改先进干涉仪的输入输出光学器件来提高对引力波源的灵敏度
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Yanbei Chen
中科院分区：
文献类型：
--
作者：
A. Buonanno;Yanbei Chen
To improve the sensitivity of laser-interferometer gravitational-wave (GW) detectors, experimental techniques of generating a squeezed vacuum in the GW frequency band are being developed. The squeezed vacuum generated from nonlinear optics has a constant squeeze angle and squeeze factor, while optimal use of squeezing usually requires a frequency dependent (FD) squeeze angle and/or a homodyne detection phase. This frequency dependence can be realized by filtering the input squeezed vacuum or the output light through detuned Fabry-Perot cavities. In this paper, we study FD input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the currently operational configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses an ordinary squeezed vacuum, but FD readout. Both schemes, which are suboptimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor. At high frequencies, the two schemes are equivalent, while at low frequencies the scheme studied in this paper gives better performance than the Harms et al. scheme, and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, for low-mass x-ray binaries, and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, such as EURO/LIGO-III $(ensuremath{sim}2012),$ with kilometer-scale filter cavities and/or mirrors with lower losses, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals.
