Search for a stochastic background of 100-MHz gravitational waves with laser interferometers

TL;DR

This paper reports a search for a stochastic gravitational wave background at 100 MHz using a novel laser interferometer setup, setting new upper limits on the energy density spectrum in this high-frequency range.

Contribution

Development of a 100 MHz gravitational wave detector with synchronous recycling interferometers and setting upper limits on GW background energy density.

Findings

Strain sensitivity of ~10^{-16} Hz^{-1/2} at 100 MHz

Upper limit of h_{100}^2 Omega_{gw} < 6 x 10^{25} in 2-kHz bandwidth

First experimental constraint on high-frequency gravitational wave background

Abstract

This letter reports the results of a search for a stochastic background of gravitational waves (GW) at 100 MHz by laser interferometry. We have developed a GW detector, which is a pair of 75-cm baseline synchronous recycling (resonant recycling) interferometers. Each interferometer has a strain sensitivity of ~ 10^{-16} Hz^{-1/2} at 100 MHz. By cross-correlating the outputs of the two interferometers within 1000 seconds, we found h_{100}^2 Omega_{gw} < 6 times 10^{25} to be an upper limit on the energy density spectrum of the GW background in a 2-kHz bandwidth around 100 MHz, where a flat spectrum is assumed.