It works by having two electric heating elements turn on and off keeping it at your desired temperature.
So I am reading today Wired Magazine's "Test" feature and under household items the Black & Decker Infrawave Speed Oven took first prize. Here is the description:
Smaller than a microwave and more versatile than a toaster, B&D’s unconventional hottie uses infrared light to cook meals on the countertop. Its two heating elements cycle on and off, employing varying wavelengths to bake, broil, or roast your chow in up to half the time it would take in a full-size gas or electic oven.Yay! My $4 toaster oven is household gizmo of the year. Sure I don't have an LCD panel, and this cooks with light bulbs (hmmmmm)but it costs $150. What is old is new.