Tip tilt mirror
A tip-tilt mirror is an example of an optic that evolves dynamically
in response to external commands. Arroyo currently supports a simple
model for the temporal evolution of a tip-tilt mirror. In this model,
the mirror moves from its current orientation towards its requested
orientation with constant angular velocity. If the mirror reaches the
requested orientation before a new command is issued, it stops
instantaneously. If it does not, the mirror instantaneously changes
direction and begins to move towards the new requested orientation
with constant angular velocity. The angular velocity is a parameter
that may be specified by the library user. The mirror aperture is a
template parameter, and may be chosen from one of several shapes.
Naturally one could write more sophisticated models for the tip-tilt
mirror either within or outside the Arroyo library.
Here is a movie showing a plane wave incident on a tip tilt mirror
with a circular aperture. The plane wave had an electromagnetic
wavelength of 1 micron. In this movie, the mirror was commanded to
move cyclically through three orientations. These orientations were
chosen to be equispaced on a circle with an amplitude of .5
arcseconds. New commands were issued every 50 milliseconds. Three
different angular velocities were chosen for this demonstration: 52,
17.32, and 5.77 arcsec/sec, and the resulting plane waves are
displayed from left to right. The intermediate value is the one for
which the mirror completes its move just as a new command is issued.
The two other values correspond to angular velocities 3 times faster
and 3 times slower than this critical value.
Tip-tilt mirror simulation
This demonstration was generated using the program tip_tilt_mirror_verification, which
is included in the Arroyo distribution.