> For the tracking system you mentioned to protect the rig, do you mean sensors to monitor energy throughput/system temperature/etc.?

For any concentrated PV system, you make use of only the direct normal isolation of the sun. All of the optical geometry (must) assume the usable light is coming in normal to the apparatus. Because the sun moves(well because the earth moves really), your apparatus needs to move too, in order to track the sun and maintain the normality of the incoming radiation, any deviation from normal will change the point in which the concentrated light will strike(which in this case is whatever receiver apparatus the rig is using). So the tracking system I am taking about is the apparatus that continuously aims the apparatus at the sun. This is not an easy problem, as you do the math and calc all the angles, but slight imperfections(which we found to be generally non-linear and thus quite hard to calibrate out) in the geometry of the rig, unevenness in terrain and other factors(you would be suprized on how many factors and affect this <wind, a flock of pigions sitting on the device, thermal expansion of the structural components of the rig, etc>).

> Do you know if the reported efficiency of quantum dot solar cells is based on input of the entire solar spectrum or from a single frequency? Do you know if multi-junction cells (or a different technology) would convert a laser into electricity more efficiently? As I understood it, multi-junction technology was specifically designed to better handle multiple wavelengths.

All reported efficiency of quantum dot solar cells is based on wide-band solar spectrum, since this is the only practical spectrum we have to operate on (
see below).

> Achieving a wide-to-single band shift with minimal loss was the mark I was aiming for, and I hope someone figures this out in my lifetime. I'm curious to see how near or embarrassingly far I was from the target.

This actually may be theoretically impossible. As mentioned in my previous response, a discovery that can do this would be a huge advance for a great many fields and applications.

> I was taking the 'intellectual philanthropy' route, but I really am curious to learn my inaccurate assumptions and misconceptions about the idea as well. The first metrics I'd like to test are the energy lost between the solar radiation input and laser output as well as the amount of loss recuperated by converting the waste heat to electricity or a laser. If the efficiency were not substantially better than directly pumping a NdCrYAG laser with solar radiation, then the idea would not be worth pursuing.

My underlying goal with the idea was to reduce the cost of electricity and reduce consumption of fossil fuels to produce electricity simultaneously. Thank you again for your input and your time.

Good luck with your continued efforts, my only suggestion would be to focus on one thing at a time, and do due diligence on the assumptions made. It was my pleasure to add my comments, solar power is the energy source of the future and increasingly, it's the energy source of today. I'm always glad to see inquiring minds pondering ways toward pushing the technology forward.

P.S.

If anybody ever gives you grief for supporting solar, just tell them you are looking into wireless fusion technology, which actually produces more energy than it consumes (which, I might add, is entirely true).