We use the
EL-16-40-TC lenses by Optotune, equipped with the industrial lens driver by
Gardasoft. The focal length of the lenses can be controlled via the analog input of the lens driver (0-10V corresponding to min. and max. focal length). Since the Redpitaya's two outputs have the voltage range
\(\pm\)1V, we are using an amplifier with Gain=10.
Optotune lenses have had different laboratory applications in microscopy(e.g. \cite{Fahrbach_2013},\cite{Jabbour_2014}), and transport of cold atoms (\cite{L_onard_2014},\cite{browaeys}).
The current setup can be seen in Figure \ref{363621}. For splitting the beam in two beams, we use a special design (see Fig. \ref{346184}): we glue an aluminium block to a rotational mount and mount a 50:50 beamsplitter and a specialty mirror from Newport on top. This allows us to rotate the lattice in the focal plane and - once used in the mixture experiment - align the lattice well with respect to the crossed dipole trap.
After the Galileit telescope, a 30cm lens focuses the two beams. We image the lattice in the focus on a CCD camera (see Fig. \ref{188236}).