Common-path lateral-shearing nulling interferometry with a Savart plate for exoplanet detection

摘要

We propose a common-path lateral-shearing nulling interferometer for direct detection of exoplanets. A Savart platenis placed between crossed polarizers to produce a lateral shear and realize fully achromatic and highly stable nullingninterference for starlight. We construct a double-shearing interferometer using two Savart plates for implementingnorthogonal x and y shears. A laboratory demonstration is carried out using a broadband light source with a band-nwidth of Δλ=λ0 ¼ 0:33 (Δλ ¼ 0:2 μm and λ0 ¼ 0:6 μm). As a result, achieved extinction levels are 4 × 10−4nat peak andn4 × 10−7 at 10λ0=DL (DL is the diameter of a Lyot stop). © 2010 Optical Society of America