Originally posted by talzamir
I thought of this by reflecting the whole situation over the mirror OA. The mirror OB is shown in the reflected area as OB', the field of the angle AOB as B'OA, and the origin of the beam of light C, as C'. The light from C hits the mirror OA and bounces off from it, but the mirror image of the reflected beam, in B'OA, continues in a incoming (incident?) be gin of the beam to the place where the mirrors join, so very close to the distance times 2.
What I don't see is the beam returning at all. You can aim the beam so it is perpendicular to the other mirror and it will of course come right back at you exactly then be gone forever.
But aiming it slightly towards the apex, where the mirrors meet, it looks to me like the place where the mirrors touch would not allow a reflection to start up going back.
Like I said, the size of the opening would get to a point where the gap would be a lot smaller than whatever wavelength you use, say one micron, and the gap gets down to say 0.1 micron, there can be no reflection since that gap is smaller than the wavelength being sent, in this case, 1 micron.
It seems to me there would be beam travel only in one direction, towards the apex where the mirrors meet and no reflection back.
Picture the mirrors as being as perfect as you can make it, say a coating of 100% pure aluminum or gold and the thickness of the gold layer is even to within one atomic size, then the gap between the mirrors would eventually reach a point where there was about one gold atom width apart, so at some point along that path, say when the gap was 2 microns apart, reflections could still take place but the gap when it is less than 0.5 microns would mean there was no room for a reflection.