title: Common-path lateral-shearing nulling interferometry with a Savart plate for exoplanet detection.
abstract: We propose a common-path lateral-shearing nulling interferometer for direct detection of exoplanets. A Savart plate is placed between crossed polarizers to produce a lateral shear and realize fully achromatic and highly stable nulling interference for starlight. We construct a double-shearing interferometer using two Savart plates for implementing orthogonal x and y shears. A laboratory demonstration is carried out using a broadband light source with a bandwidth of Δλ/λ(0)=0.33 (Δλ=0.2 μm and λ(0)=0.6 μm). As a result, achieved extinction levels are 4 × 10(-4) at peak and 4 × 10(-7) at 10λ(0)/D(L) (D(L) is the diameter of a Lyot stop).
authors.affiliation: Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan. nmurakami@eng.hokudai.ac.jp
authors.forename: Naoshi
authors.initials: N
authors.lastname: Murakami
authors.forename: Naoshi
authors.initials: N
authors.lastname: Baba