I have always had great difficulty in understanding light, specifically, the particle-wave duality and the multitude of energy levels.
By “phase information” I presume you mean something like infrared, visible, ultraviolet, etc.
My original thought on this subject was, “Why not cover acres of ground with CCDs instead of spending 20 years casting and grinding mirrors?”
I had always assumed the issue was computer processing power for trillions and trillions of pixels.
That's not it. "Phase information" charactises "coherence", as a laser, for example, is a coherent beam of light. This is what allows it to produce interference patterns.
You can shine a laser through a lens, and bounce it off mirrors, and this coherence will be preserved, but CCD's require absorption of photons, and so the information thus recorded is reduced to INTENSITY, as opposed to AMPLITUDE, which preserves or carries "phase information". So a surface of CCDs can never duplicate an optical mirror surface.
This is according to my own understanding, and I stand ready to be corrected, ( but it would take some doing! )