Advancing Apodization Techniques: Optimizing Interferometric Apodization by Homothety for Exoplanet Detection

Abstract New apodization techniques are emerging rapidly to enhance the coronagraphs’ rejection capabilities and refine the optics for directly detecting exoplanets. One such technique, Interferometric Apodization by Homothety (IAH), involves splitting the incident Point Spread Function (PSF) into two using a 50 : 50 beamsplitter. One of the resulting PSFs has its amplitude reduced by a factor γ and its transverse dimension expanded by a factor ƞ . By combining these two PSFs, an apodized PSF is generated. In this study, we will use the standard values of γ and ƞ for both rectangular and circular apertures. We implement this approach in the laboratory using a Mach-Zehnder Interferometer with Cube Beamsplitters, chosen for their advantages over Plate Beamsplitters, including easy integration at a 0 ° angle of incidence and equal optical path lengths for reflected and transmitted light. This technique shows significant promise, achieving a contrast of approximately 5.10 −3 at small angular separations around 2.8 λ /D.