Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

GALILEO: Galactic Axion Laser Interferometer Leveraging Electro-Optics

Reza Ebadi, David E. Kaplan, Surjeet Rajendran, Ronald L. Walsworth

TL;DR

GALILEO introduces a high-frequency, wide-mass search for light dark matter by converting DM-induced electric fields into refractive-index modulations in nonlinear EO materials and reading them with a resonant laser interferometer. The method relies on the Pockels effect to produce δn from the DM field, with detectable phase shifts amplified by Fabry-Perot cavities in an asymmetric Michelson design. Projections for axion and dark photon DM show the approach can explore uncharted regions of parameter space between $0.1$ and $10^3\,\mu\mathrm{eV}$, including regimes challenging for microwave cavity haloscopes, and offer a path toward probing the QCD axion DM parameter space with future EO advances. Dark photon DM searches benefit from relaxed design requirements (no strong magnet), while axion searches hinge on magnetized EO samples; the technique could substantially broaden experimental reach in the near term and beyond with material and optical improvements.

Abstract

We propose a novel experimental method for probing light dark matter candidates. We show that an electro-optical material's refractive index is modified in the presence of a coherently oscillating dark matter background. A high-precision resonant Michelson interferometer can be used to read out this signal. The proposed detection scheme allows for the exploration of an uncharted parameter space of dark matter candidates over a wide range of masses -- including masses exceeding a few tens of microelectronvolts, which is a challenging parameter space for microwave cavity haloscopes.

GALILEO: Galactic Axion Laser Interferometer Leveraging Electro-Optics

TL;DR

GALILEO introduces a high-frequency, wide-mass search for light dark matter by converting DM-induced electric fields into refractive-index modulations in nonlinear EO materials and reading them with a resonant laser interferometer. The method relies on the Pockels effect to produce δn from the DM field, with detectable phase shifts amplified by Fabry-Perot cavities in an asymmetric Michelson design. Projections for axion and dark photon DM show the approach can explore uncharted regions of parameter space between and , including regimes challenging for microwave cavity haloscopes, and offer a path toward probing the QCD axion DM parameter space with future EO advances. Dark photon DM searches benefit from relaxed design requirements (no strong magnet), while axion searches hinge on magnetized EO samples; the technique could substantially broaden experimental reach in the near term and beyond with material and optical improvements.

Abstract

We propose a novel experimental method for probing light dark matter candidates. We show that an electro-optical material's refractive index is modified in the presence of a coherently oscillating dark matter background. A high-precision resonant Michelson interferometer can be used to read out this signal. The proposed detection scheme allows for the exploration of an uncharted parameter space of dark matter candidates over a wide range of masses -- including masses exceeding a few tens of microelectronvolts, which is a challenging parameter space for microwave cavity haloscopes.
Paper Structure (5 sections, 9 equations, 2 figures)

This paper contains 5 sections, 9 equations, 2 figures.

Table of Contents

  1. Electro-optic effect.---
  2. Dark matter-induced electric field.---
  3. Detection scheme.---
  4. Experimental feasibility and projected sensitivities.---
  5. Summary.---

Figures (2)

  • Figure 1: Schematic of the proposed laser interferometer-based light dark matter (DM) detector, GALILEO. The Fabry-Perot (FP) cavities are resonant with the light-DM mass $L=2j\pi/m_\mathrm{DM}$. The electro-optical (EO) material's thickness is limited to $L_0\leq\pi/m_\mathrm{DM}$ to preserve the oscillatory DM signal while averaging over laser travel time through the material. Note that the EO material needs to be exposed to a large, uniform magnetic field for axion-induced effects. See text for details.
  • Figure 2: Projected sensitivities of the GALILEO experiment for axion (Left) and dark photon (Right) dark matter searches. The red shaded area is within the reach of the proposed detector. Orange (red) lines: $\mathrm{LiNbO_3}$ ($\mathrm{BaTiO_3}$) as target electro-optical material. Dashed lines: 1 s averaging at each frequency band $\Delta f=m_\mathrm{DM}/(2\pi\mathcal{F})$. Dash-dotted lines: extended search time of $290$ s per bin, equivalent to scanning a decade in mass for about 3 years. Solid lines: $290$ s averaging time per bin and 10 dB squeezing of light input to the interferometer. Vertical gray dashed lines indicate the number of EO material pieces $N=1,3,$ and $10$ needed to achieve maximum sensitivity at representative DM masses if each EO material has a thickness of $L_0=\pi/m_\mathrm{DM}$. See text for details. Dark (light) gray shaded areas are excluded by terrestrial experiments (astrophysical observations). Green: QCD axion parameter space. Blue: excluded by dark photon DM cosmology Arias:2012az. Existing limits are adapted from ref. AxionLimits.