When I was a kid(~1980), I remember our microwave had a removable temperature probe you could insert into the food. I don't know if it was just for informative purposes or if it controlled the cooking however.
Those disappeared, though, because they're solving the wrong problem.
Those would tell you when the center of your food was cooked, but by then the outside of your food was insanely over-cooked. Most of your chicken breast has turned into dried-out rubber.
The real problem isn't to get the center hot enough, that's easy. It's to prevent the outside from getting too hot. And you need a camera for that.
I think a probe would be really great, because knowing the surface temp doesn't tell you how hot the thickest part of the food is. Although GP has an interesting point that if you cycle it for long enough, I guess the heat should approach equilibrium and the surface and insides should match.
Yup that's exactly the idea, for it to approach equilibrium.
And the microwave should be able to deduce how close it is by the rate of cooling of non-hotspots while the cycle is off. If it's cooling quickly, the inside is still frozen. If it isn't cooling at all, the inside is nice and warm.
