Gravitational Photon Polarization Twist to Probe the Early Universe and the Galactic Center

TL;DR

This paper proposes a space-based experiment to detect gravitational wave backgrounds by observing polarization changes in laser photons, which could reveal signals from the early universe and galactic center pulsars.

Contribution

It introduces a novel method using photon polarization twist to detect gravitational wave backgrounds, combining laser pulses and birefringent materials in space-based setups.

Findings

Potential to detect early universe gravitational waves.

Capability to identify pulsars in the galactic center.

Method sensitivity comparable to LISA mission.

Abstract

It is known that gravitational wave backgrounds (GWBs) change the polarization state of photons. This letter explores the possibility of using this effect to detect GWBs. The proposed experiment features a vertically polarized laser pulse traveling through a GWB before reaching a birefringent material which separates photons by polarization. Photons that emerge the birefringent material horizontally polarized are counted as signal photons. A space-based setup of a million km (comparable to the LISA mission) with a millisecond laser pulse is capable to detect the hypothetical pulsars responsible for the excess of gamma rays from the galactic center. Varying the duration of the pulse can reveal a variety of GWBs from the early Universe as well.