Abstract
ABSTRACTIn this paper we give the principle of an achromatic Prolate Apodized Lyot Coronagraph (PALC), which uses a wavelength‐dependent transmission of the entrance aperture to compensate for the chromatic effect of diffraction. For a fixed mask size, the aperture transmission must follow a prolate function of strength that is variable with the wavelength so that the coronagraph operates as a perfect PALC for each wavelength of the spectral bandwidth. The apodization must be stronger in the blue than in the red. The residual stellar light, reduced to a very low level for a small mask size, appears mainly in the red part of the spectral bandwidth. Numerical simulations are given for the perfect case, and solutions for realizing the needed wavelength‐dependent transmission using a Mach‐Zehnder interferometer are considered.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call