Detecting gravitational waves with light

TL;DR

This paper provides an accessible overview of gravitational wave detection methods using light, covering recent pulsar timing array results, interferometric detections like LIGO, and future space-based detectors such as LISA.

Contribution

It offers a simple, unified explanation of gravitational wave detection via light, suitable for undergraduates, including recent PTA findings and theoretical foundations.

Findings

Recent PTA detections of low-frequency gravitational waves

Unified explanation of light-based detection methods

Derivation based on basic principles and Einstein's equivalence principle

Abstract

The strong evidence for low-frequency gravitational waves from pulsar timing arrays (PTAs), published in 2023, has widened the scope for teaching about gravitational wave astronomy. This article provides a simple, unified overview of the detection of gravitational waves using light waves that encompasses the recent PTA detections, the by-now classic interferometric detections using LIGO and similar detectors, and the yet-to-be-accomplished detections using long-arm detectors like the spaceborne LISA. The presentation is at a level accessible for undergraduate students. The influence of gravitational waves on light is derived in a way that makes use only of basic gravitational wave properties and Einstein's equivalence principle.