Am looking to build a solar tunnel that would not only redirect solar visible light radiation, but also heat, with minimum losses. Basically need to deflect angle of incident radiation by around 30 degrees. Am considering an inverted truncated cone design, with a polished inner surface, which would be slightly tilted with respect to incident radiation. My question is - what section would be ideal for the inner surface - would a conical surface work best as planned, or is a cylinder better? - would a planar surface work, or would it be more efficient with a curved inner surface, parabolic or elliptical ? Am looking to carry the heat / light deep down into a 50 metre deep distance. Would any lens be able to do that? Do not need to concentrate, just redirect the radiation. Am not sure if there are any lenses that can carry light that far ?