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Abstract The technologies used in the manipulation of light can be used to do analogue simulations of physical systems with wave-like equations of motion. This analogy is maximized by the use of all the degrees of freedom of light. The Helmholtz equation in physical optics and the Schodinger equation in quantum mechanics share the same mathematical form. We use this connection to prepare non-diffracting optical beams representing the spatial and temporal dynamics of a nonlinear physical system: the quantum pendulum. By using the propagation coordinate to represent time in the quantum problem, we are able to analogue-simulate quantum wavepacket dynamics. These manifest themselves in novel optical beams with rich three-dimensional structures, such as rotation and sloshing of the light's intensity as it propagates. Our experimental results agree very well with the predictions from quantum theory, thus demonstrating that our system can be used as a platform to simulate the quantum pendulum dynamics. This three-dimensional light-sculpting capability has the potential to impact fields such as manipulation with light and imaging.
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(2D+1) pendulum beams: non-diffracting optical spatial wavepackets that simulate quantum pendulum dynamics
The similarity between the 2D Helmholtz equation in elliptical coordinates and the Schr¨odinger equation for the simple mechanical pendulum inspires us to use light to mimic this quantum system. When optical beams are prepared in Mathieu modes, their intensity in the Fourier plane is proportional to the quantum mechanical probability for the pendulum. Previous works have produced a two-dimensional pendulum beam that oscillates as a function of time through the superpositions of Mathieu modes with phases proportional to pendulum energies. Here we create a three-dimensional pendulum wavepacket made of a superposition of Helical Mathieu-Gaussian modes, prepared in such a way that the components of the wave-vectors along the propagation direction are proportional to the pendulum energies. The resulting pattern oscillates or rotates as it propagates, in 3D, with the propagation coordinate playing the role of time. We obtained several different propagating beam patterns for the unbound-rotor and the bound-swinging pendulum cases. We measured the beam intensity as a function of the propagation distance. The integrated beam intensity along elliptical angles plays the role of quantum pendulum probabilities. Our measurements are in excellent agreement with numerical simulations.
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- Award ID(s):
- 2011937
- PAR ID:
- 10337008
- Date Published:
- Journal Name:
- Complex Light and Optical Forces XVI, 1201704
- Volume:
- 1201704
- Page Range / eLocation ID:
- 51
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1117/12.2627732
