Improved linear response in a modal wavefront sensor.

The modal wavefront sensor provides a direct and less computationally intensive way, relative to a zonal wavefront sensor, of estimating the various aberration modes present in a beam of light. Such wavefront sensors are particularly useful when the optical system concerned is affected by a limited number of aberration modes. Unfortunately, the basic design of the modal wavefront sensor suffers from reduced linear response and intermodal crosstalk.

Note: Current induced fluctuations in the orientation of the beam diffracted by a liquid crystal spatial light modulator.

In this paper, we report a peculiar movement of the beam cross sections associated with both the diffracted and undiffracted laser beams from a liquid crystal spatial light modulator (LCSLM). The beam movement becomes noticeable when the beam position is monitored continuously for several hours. We perform experiments to show that the beam movement is non-mechanical in nature and is connected with the power on/off instants of the LCSLM as well as the heat conductivity of the mounting slab which acts as the rigid support to the LCSLM panel.