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After learning about Lloyd's mirror from Wikipedia, I watched a video demonstration of the experiment in YouTube where a laser was used as the light source. In Young's Double Slit Experiment (YDSE), a laser is used to illuminate the two slits simultaneously as it's a good coherent source and it's monochromatic. But in Lloyd's mirror, I think, even if we don't use laser, instead use a good monochromatic light source, we could see the interference pattern, because the both the source and its reflection on the mirror, act as coherent source even if the original source is not a laser as any abrupt phase change in the original source will be equally compensated by the mirror, and so the phase difference between the two remains constant with time. So, is it really necessary to use laser as a source of light in Lloyd's mirror?

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In the original experimental set up a conventional monochromatic source and also a white light source.were used. At that time lasers had not been invented.

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Loyd's Mirror experiment is really just a different version of the two-slit experiment. Instead of asking which slit a photon goes through on its way to the screen, we ask whether the photon bounces off the mirror or goes directly to the screen. If we can answer the question, we won't see interference fringes. The coherence requirements are the same for the two experiments.

Monochromatic (laser) light will produce plenty of clear fringes; broad-spectrum light produces fringes that are clear for each wavelength component but which, all together, blur each other out because their fringe spacing increases with wavelength. Broad spectrum light usually produces distinguishable fringes only very close to where the mirror contacts the screen (where the two path lengths are nearly identical).

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