TPF-C Technology Plan - Exoplanet Exploration Program - NASA

Instrument Technology and Advanced Concepts
wl_02
1.000000
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Figure 6-2. Left: Deep nulls from a laser source under control of a metrology system. Right:
Deep nulls from an unpolarized white light source at 10% bandpass around 635 nm.
6.2.1.2 MEMS Deformable Mirror
A segmented MEMS deformable mirror (DM) is currently in development led by Boston
University. 44 A design has been completed for a DM with 61 segments, each with tip, tilt, and
piston, shown in Figure 6-3.
Figure 6-3. Left: Design of a 61-segment pathfinder DM. Center: Schematic placement of
actuators under each segment. Right: Photomicrograph of segments from this device.
6.2.1.3 Single Mode Fiber Array
The alignment of the lens array to fiber array must be performed to a precision level of 0.5 μm
because the mode field diameter of common visible single mode optical fibers are small and their
numerical apertures are relatively large. Currently, two independent technologies are being
pursued for the fiber array. 45
44 Krulevitch, P. A. Bierden, P, A., Bifano, T. G. Carr, E. Dimas, C. E. Dyson, H., Helmbrecht, M. A.
Kurczynski, P. L Muller, .R. S. Olivier, S. S. Peter, Y. Sadoulet, B., Solgaard, O. Yang, E. H., 2003,
“MOEMS spatial light modulator development at the Center for Adaptive Optics," Proc SPIE, 4985, 26.
45 Liu, D.T., Levine, B.M., Shao, M., Aguyao, F. (2005), “Single Mode Fiber Array for Planet Detection
using a Visible Nulling Interferometer”, Proc. IEEE Big Sky Conference.
97