  The focal-plane camera of $\gamma$-ray telescopes frequently uses light
concentrators in front of light sensors. The purpose of these concentrators is
to increase the effective area of the camera as well as to reduce the stray
light coming at large incident angles. These light concentrators are usually
based on the Winston cone design. In this contribution we present the design of
an hexagonal hollow light concentrator with a lateral profile optimized using a
cubic B\'ezier function to achieve a higher collection efficiency in the
angular region of interest. The design presented here is optimized for a
Davies-Cotton telescope with primary mirror of about 4 meters of diameter and
focal length of 5.6 m. The described concentrators are part of an innovative
camera made up of silicon-photomultipliers sensors, although a similar approach
can be used for other sizes of single-mirror telescopes with different camera
sensors, including photomultipliers. The challenge of our approach is to
achieve a cost-effective design suitable for standard industrial productions of
both the plastic concentrator substrate and the reflective coating. At the same
time we maximize the optical performance. In this paper we also describe the
optical set-up to measure the absolute collection efficiency of the light
guides and demonstrate our good understanding of the measured data using a
professional light tracing simulation.
