Interferometric Differential High-Frequency Lock-In Probe for Laser-Induced Vacuum Birefringence

TL;DR

This paper introduces a novel interferometric high-frequency lock-in technique using pulsed lasers and optical cavities to measure laser-induced vacuum birefringence, reducing systematic errors and optimizing laser power use.

Contribution

It presents a new measurement method combining cavity-enhanced pulses and differential detection to improve vacuum birefringence measurements with simpler setup and better systematic error mitigation.

Findings

Enhanced measurement sensitivity through lock-in detection

Reduced systematic errors from cavity birefringence

Efficient use of laser power in the experimental setup

Abstract

We propose a measurement of laser-induced vacuum birefringence through the use of pulsed lasers coupled to femtosecond optical enhancement cavities. This measurement technique features cavity-enhanced pump and probe pulses, as well as an independent control pulse. The control pulse allows for a differential measurement where the final signal is obtained using high-frequency lock-in detection, greatly mitigating time-dependent cavity birefringence as an important and possibly prohibitive systematic effect. In addition, the method features the economical use of laser power, and results in a relatively simple experimental setup.