TY - JOUR AU - John Hall AU - Jun Ye AU - L Ma C2 - Physical Review A (Atomic, Molecular and Optical Physics) DA - 2000-07-01 LA - en M1 - 62 PB - Physical Review A (Atomic, Molecular and Optical Physics) PY - 2000 TI - Measurement of Mirror Birefringence at the Sub-PPM Level: Proposed Application to a Test of QED ER -