Searching for minicharged particles via birefringence, dichroism and Raman spectroscopy of the vacuum polarized by a high-intensity laser wave

TL;DR

This paper explores how high-intensity laser fields affect vacuum optical properties like birefringence and dichroism to search for minicharged particles, proposing polarimetric and Raman spectroscopy methods to set experimental bounds.

Contribution

It introduces new theoretical expressions for vacuum optical effects in intense laser fields and suggests experimental techniques for detecting minicharged particles using these effects.

Findings

Vacuum birefringence and dichroism are enhanced near pair-production thresholds.

High-precision polarimetric experiments can set bounds on minicharged particles.

Raman-like electromagnetic waves offer an alternative detection method.

Abstract

Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles.