*Experimental alert:* Someone may be able to answer this question experimentally simply by going to a shopping mall and finding the right piece of holographic jewelry.

[At least one non-SE answer site][Holographic_Mirror] clearly and in detail says that the holographic images cannot act as mirrors. That is, a hologram cannot reflect an image of yourself back at you. The simple and very reasonable explanation for this is that you were not there when the hologram interference patterns were originally constructed.

Alas, I find this reasonable-sounding answer unsatisfying for two reasons: (1) Somewhere I still have a transmission hologram of the insides of a watch. I clearly recall watching a bright spot move left and right on the image of a curved metal part within the watch as I moved a background light move left and right in front of the hologram. While a moving bright spot is hardly a complete image, it does indicate that a hologram is capable of a visible response to an object not in the original hologram. (2) I'm not aware of anything from diffraction theory that says you *cannot* use multilayer diffraction patterns to create simple, mirror-like reflecting surfaces. (Nor am I aware of anything that says you *can*, either.)

So, experimenters: Does anyone out there have a hologram in hand that seems to reflect non-trivial light patterns?

And theorists: Regardless of how one would create it in the lab, is it mathematically possible to create multilayer diffraction patterns that, like metallic mirrors, would reflect light in a way that depends on the incident angle of the light?

[Holographic_Mirror]: http://askville.amazon.com/transmission-hologram-mirror-reflect-images/AnswerViewer.do?requestId=125019