Abstract | ||
MACROSCOPIC OBSERVATION OF QUANTUM EFFECTS: A STUDY ON THE
FORMATION OF INTERFERENCE FRINGES WITH POLARIZED LIGHT.
Jose Mawyin, Mirna Lerotic, John Noe, Harold Metcalf,
Laser Teaching Center, Department of Physics and Astronomy,
University at Stony Brook.
The goal of this project is to demonstrate quantum-mechanical
effects--that usually appear only at at microscale at atomic
distances--on a macroscopic level. The experiment is based on a
phenomenon called photon tagging, in which position information
is ascribed to the photons. This is sometimes called referred as
the "which way" (welcher Weg) determination. The tagging of the
photons is achieved by means of polarizers in a optical
interferometer.
The interferometer used is of the Mach-Zender type. The initial
beam of laser light is first split into two different branches by
a `beam splitter` which uses a special reflecting surface to
divide the initial light into to two different branches. Each
branch is then turned by a highly reflective mirror back to a
second beam splitter, where the two branches are re-joined.
Finally, light leaving the second splitter falls on a screen or
detector. As described by the wave theory of light, a series of
regions of light and darkness called fringes are produced. They
are caused by the different paths taken by both brances which
cause a phase difference. However, the fringes, disappear if
linear polarizer filters of different orientation are placed in
the two branches before unification in the second splitter. This
is a extrapolation of quantum behavior on a macroscopic level,
because the interference can occur even if only a single photon
is moving across the system is in any given time. This may sound
counterintuitive, but the photon actually interacts with itself
because it takes both paths at the same time. Our project
involves many more photons but the behavior is the same.
Interesting things happen when photons pass through our
polarizers. This tags the path taken by the photons. The tagging
in a way makes the photon to take either path or the another, but
not both at the same time. Which implies that it can not
interact with itself. And finally it would not produce an
interference pattern. The nature of this behavior is beautiful by
itself. However, we are planning to place a third polarizer after
the second beam splitter. In order to normalize both branches to
a single polarization configuration. Theoretically, we expect to
find that this addition will have great significance in the
formation or not of interference fringes. The implications of
this behavior are staggering. The whole formation of the fringes
heavily depend on the knowledge of position of photons. And
thanks to the massive amount of interaction we will able to see
it with our own eyes.
The parts of our project have been ordered and should arrive soon. We expects to collect meaningful data shortly thereafter. In a later study, more complicated variations of linear and elliptical polarizers will be tested in the formation on interference fringes. The results of this combination should prove harder to anticipate. The humble photon, only shows his full beauty when a little mystery about his behavior is left unknown . | ||
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