I think it can be done. I am looking at doing the same myself. It seems like the mirror would need to be the same size as the area you want to cover or you could diffuse it but then you would lessen the strength of the suns rays so you would not have a 1:1 relationship. Not sure if you want heat or just light but here is a place to start.
Here is a link I found online http:/www.practicalsolar.com. A place that actually sells such products that will also track the sun to ensure it keeps pointing in the right direction.
Could always try a crazy Solar Tube contraption depending on the lay of your land. These are easy to find online. Typically they are used for bringing light in to your house (similar to a sunlight) in hard to reach areas.
grass+sunlight
Use Sunlight and Grass
There is no sunlight for the grass to grow / survive.
Any area of grass that is shaded from the sun by a crate laying (for instance, on a lawn) would result in the grass becoming lank, weak and less green. Eventually, the area of grass shaded would die and become an area of bare earth.
grass+sunlight
The only source of sunlight is the sun.
That is the grass dying. Plants need sunlight in order to photosynthesize. Covering grass with a board is depriving it of sunlight.
they dont get sunlight
The grass turns green when it is exposed to sunlight.
Grass uses most of the energy it gets from sunlight for its own life processes.
Tall fescue is actually a really good grass type for densely shaded areas.
Turtle grass eats CO2 and sunlight