TPF-C Technology Plan - Exoplanet Exploration Program - NASA

Optics and Starlight Suppression Technology
Figure 3-3. Binary 1-sinc 2 mask (left) produced by e-beam lithography of aluminium on
glass for f/28.55 and a wavelength 785 nm, binary continuous sin 2 mask pattern (middle), and
binary discontinuous sin 2 mask pattern (right).
Figure 3-4. Bar code masks and shaped elliptical masks. From left to right: 1-D bar code
mask; 2-D bar code mask; four-aperture mask elliptical mask; multi-aperture elliptical mask.
been designed and fabricated at JPL. Figure 3-3 shows optical microscope images of such
patterns in a mask that is currently under test in the HCIT for direct comparison with the HEBS
mask.
Pupil plane masks: Pupil masks of various designs are being studied theoretically and
experimentally, primarily at Princeton University by a group headed by Professor Jeremy Kasdin
under JPL subcontract. A parallel effort is also underway for accurate vector diffraction
modeling of the system by a group headed by Professor Andy Neureuther at UC Berkeley 4 and in
association with Ball Aerospace. Figure 3-5 shows the modeling approach used at Ball
Aerospace to integrate numerical results into an end-to-end performance prediction model.
Several mask designs are being explored and reported 5,6 . A few examples of such pupil plane
masks are shown in Figure 3-4.
3 Shaklan S.B. and Green J.J., “Low order Aberration Sensitivity of Eighth-Order Coronagraph Masks,”
Ap.J. 628, pp. 474–77 (2005).
4 D. Ceperley et al., “Vector Scattering Analysis of TPF Coronagraph Pupil Masks,” Proc. SPIE 5526B
pp. 228-239, SPIE Denver Annual Meeting, 2004.
5 Kasdin, N.J., R. J. Vanderbei, M.G. Littman, M. Carr, and D.N. Spergel, "The Shaped Pupil
Coronagraph for Planet Finding Coronagraphy: optimization, sensitivity, and laboratory testing," in
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