The POLARBEAR experiment achieved first light in Chile on January 10th, 2012 with observations of Saturn. Below we show signals from two polarization-sensitive detectors in one array pixel. Below, the 1284-bolometer array is being installed. At the bottom, a beam map from Jupiter is shown. The team is currently preparing the system for science observations in April, when weather conditions in Chile become suitable.

(a) The map on the left reveals a clear detection of E-mode polarization in the CMB. E-mode polarization has already been measured by several experiments. The source of this polarization is the acoustic oscillations of the early universe. (b) Oon the left we have a "null map" which shows a map with the data split in half and differenced, so that only noise should remain. This low noise level will allow us to also characterize the B-mode polarization.

(c) We use the polarized supernova remnant Tau A (also known as the Crab Nebula) as a polarization calibrator for the instrument. This is a map of the polarized intensity and polarization direction of Tau A, produced from data taken over the past 1.5 years.