A rotatable element includes a plate, a plate support, a cradle and a cradle
support.
The plate is coupled to the cradle via the plate support. The cradle is coupled
to a surrounding frame by the cradle support. The plate and cradle are suspended
over a cavity so that, in conjunction with the plate support and the cradle support,
both the plate and cradle are capable of freely rotating about different axes of
rotation when suitably actuated. Since the plate is capable of rotating independently
of the cradle, yet also rotates when the cradle is rotated, the plate is rotatable
about two axes of rotation. In some cases, the axis of rotation of the plate is
perpendicular to the axis of rotation of the cradle. Since the cradle does not
surround the plate, the plates of adjacent rotatable elements can be placed very
close to one another (i.e., as close as about 1 micron) to provide, for example,
an array of very-closely-spaced mirrors.