By 1816 he was a strong advocate of a wave theory of light, agreeing with Fresnel and opposed to Biot and Laplace who advocated a corpuscular theory. Fresnel became a good friend of Ampère's and lodged at Ampère's home from 1822 until his death in 1827.
Sa pamamagitan ng 1816 siya ay isang malakas na tagapagtaguyod ng isang kaway teorya ng ilaw, sumasang-ayon sa Fresnel at laban sa Biot at Laplace na advocated isang korpuskulo theory. Fresnel ay naging isang mabuting kaibigan ng Ampère's at lodged at Ampère bahay mula 1822 hanggang sa kanyang kamatayan sa 1827.