A Measurement of the Cosmic Microwave Background Lensing Potential and Power Spectrum from 500 deg2 of SPTpol Temperature and Polarization Data

We present a measurement of the cosmic microwave background lensing potential using 500 deg2 of 150 GHz data from the SPTpol receiver on the South Pole Telescope. The lensing potential is reconstructed with signal-to-noise per mode greater than unity at lensing multipoles L lesssim 250, using a quadratic estimator on a combination of cosmic microwave background temperature and polarization maps. We report measurements of the lensing potential power spectrum in the multipole range of 100 < L < 2000 from sets of temperature-only (T), polarization-only (POL), and minimum-variance (MV) estimators. We measure the lensing amplitude by taking the ratio of the measured spectrum to the expected spectrum from the best-fit Λ cold dark matter model to the Planck 2015 TT + low P + lensing data set. For the minimum-variance estimator, we find ${A}_{\mathrm{MV}}=0.944\pm 0.058(\mathrm{Stat}.)\pm 0.025\ (\mathrm{Sys}.);$ restricting to only polarization data, we find ${A}_{\mathrm{POL}}=0.906\pm 0.090\ (\mathrm{Stat}.)\pm 0.040\ (\mathrm{Sys}.)$. Considering statistical uncertainties alone, this is the most precise polarization-only lensing amplitude constraint to date (10.1σ) and is more precise than our temperature-only constraint. We perform null tests and consistency checks and find no evidence for significant contamination.