GRED: Double slit with fast lensless video screen

[RJN]

Guess the Result of the Experiment of the Day (GRED)

A classic double slit experiment is done with light (photons) that creates an interference pattern on a distant image screen. The experiment is repeated, except now the image screen is replaced by an extremely high speed video sensor array, without a lens. The video sensors act just like the old image screen, except now each frame of the video is precisely time tagged. The time of release of single source photons is also recorded precisely. Adding all of the frames, what pattern accumulates on the video camera's screen?

Here is an ASCII schematic:

Code: Select all

                                                            
                               |                                |
     s                         |                                |
                               |                                |

    Photon                   Double                            Fast
    Source                    Slit                            Video 
                             Screen                           Screen

Aspect to consider: if the precise time-of-flight time for a photon is known, won't it be possible to compare this with the time-of-flight it would take for this photon to go through each slit, and therefore determine which slit this photon went through? And if such "which-path" information is known -- won't this destroy the interference pattern?

Please do NOT post any answers or comments with spoilers here. Answers and comments with spoilers are encouraged in GRED Answer post here: http://asterisk.apod.com/vie ... 30&t=19826 . Please check back there later -- what I believe to be the correct answer will be posted there a few days after this initial post.

Comments or questions here -- without spoilers -- are OK. In particular, questions about the experimental setup are OK.

[alter-ego]

Robert - Just to clarify, I assume there is no "sharp-eyed" lens on the camera. True? I.e. the slits are not resolved?

[RJN]

Excellent point, ae. This time I was assuming a lensless system. Therefore, picture the video camera with no lens attached -- a bare photosensor array. I have now clarified this in the initial posts. - RJN

[brazosastro]

This sounds like something that could be done pretty easily (i.e., no LHC needed).

M

[Star*Hopper]

You're kidding, right? That's so simple, I'm gonna let my driver back there answer that.

[jfreed27]

How will "knowing" effect phenomena?

[webo]

I'm not sure from the reading of the question just how the video screen is timed with respect to the light signals?
Are they simultaneously opened with the/each signal? Is this a "photon entanglement" setup?

[alter-ego]

I'm not sure from the reading of the question just how the video screen is timed with respect to the light signals?
Are they simultaneously opened with the/each signal? Is this a "photon entanglement" setup?

I believe you should consider this problem a "thought experiment" where you can ignore details of how timings are done. Consider the frame collection to be fast enough (with a timestamp for each frame) to allow "precise" photon arrival times. The photon departure time is also assumed to be known, but the detection method is not mentioned. Is this a photon entanglement setup? Per se, no. My view of this problem is you are equipped with "ideal" measurement equipment.

[aeqel]

How will "knowing" effect phenomena?

Think superposition I assume.

[madmagician]

At what rate are photons being released? Does it matter if there is only one? [Or 1024, or a practically continuous stream].

[shoreline1]

Well, I do like llamas.