First results from the Axion Dark-Matter Birefringent Cavity (ADBC) experiment

Abstract

Axions and axion-like particles are strongly motivated dark matter candidates that are the subject of many current ground based dark matter searches. We present first results from the Axion Dark-Matter Birefringent Cavity (ADBC) experiment, which is an optical bow-tie cavity probing the axion-induced birefringence of electromagnetic waves. Our experiment is the first optical axion detector that is tunable and quantum noise limited, making it sensitive to a wide range of axion masses. We have iteratively probed the axion mass range 40.9-43.3$\text{ neV/c}^2$, 49.3-50.6$\text{ neV/c}^2$, and 54.4-56.7$\text{ neV/c}^2$, and found no dark matter signal. On average, we constrain the ALP-photon coupling at the level $g_{aγγ} \leq 1.9\times 10^{-8} \text{ GeV}^{-1}$. We also present prospects for future axion dark matter detection experiments using optical cavities.

Figures (8)

• Figure 1: Experimental setup: bow-tie cavity with A, D, B, C mirrors. $\hat{s}$-polarized pump field from a 1064nm Nd:YAG laser enters the cavity at mirror A and is locked to the cavity using a PDH lock. ALP generated $\hat{p}$-polarized sidebands at the cavity splitting frequency $\omega_a=\omega_{\text{sp}}$ are resonant in the cavity. Heterodyne readout is performed using pump and signal field transmitted at mirror C.
• Figure 2: Mean-averaged PSD data (blue), neighboring-bin running median to estimate the mean (pink), and points that lie above the detection threshold (green) for the second dataset. We also show a portion of the data overlayed with the expected axion lineshape (orange), where it can be seen that the data peak is much narrower.
• Figure 3: 95% upper limit on $g_{a\gamma\gamma}$ placed by the first run of the ADBC experiment. We have bounds from five datasets over axion frequency ranges 9.8810.45, 11.9212.22, and 13.1213.69 with an average sensitivity of 1.9e-8^-1.
• Figure 4: Current bounds and future projections from implementations of optical ALP polarimetry. We show ADBC's current data run, along with a dashed line indicating the apparatus's current sensitivity if we performed a search over the full mass range. Sensitivities are also shown for a future ADBC upgrade still using heterodyne readout, as well as the same apparatus operated with single photon readout. Current bounds from other ALP polarimetry experiments include LIDA (shown in plot) and DANCE ($g_{a\gamma\gamma} \leq \qty{8e-4}{\giga\eV^{-1}}$ for $\qty{e-14}{\eV} < m_a c^2 < \qty{e-13}{\eV}$). The blue regions show bounds from terrestrial ALP searches, in which we highlight the bounds from the solar axion search CAST CAST:2007jps, and the toroidal magnet searches ABRACADABRA Salemi:2021gck and SHAFT Gramolin:2020ict. The green regions show various astrophysical constraints, particularly constraints from black hole superradiance AxionLimits.
• Figure 5: Experimental setup: bow-tie cavity with A, D, B, C mirrors. $\hat{s}$-polarized pump field enters the cavity at mirror A and is locked to the cavity using a PDH lock. ALP generated $\hat{p}$-polarized sidebands at the caity splitting frequency $\omega_a=\omega_{\text{sp}}$ are resonant in the cavity. Heterodyne readout is performed using pump and signal field transmitted at mirror C.