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Excitation of vibrational modes in a levitated sphere

The objective of this project is to develop a stimulated Raman scattering setup (see figure) and to characterize the vibrational modes (acoustic phonons) of a levitated silica sphere. The work involves microwave electronics, optomechanics, and nonlinear optical spectroscopy.

The center-of-mass dynamics of a silica sphere (diameter 200 nm) that is trapped at a
focus of laser beam is defined by its translational and rotational degrees of freedom. In
addition to its center-of-mass degrees of freedom the sphere has also internal degrees
of freedom (vibrations), which are analogous to the ringing of a wine glass. The vibrational
modes have frequencies Omega m and can be excited by a nonlinear optical process, called stimulated Brillouin scattering [1].
Energy conservation requires Omega m = w1-w2.
The output signal will be at a maximum
whenever the frequency difference w1 − w2 is resonant with a vibrational frequency Omega m.
The objective of this project is to develop a stimulated Raman scattering setup (see figure) and to characterize the vibrational modes (acoustic phonons) of a levitated
silica sphere. The work involves microwave electronics, optomechanics, and nonlinear
optical spectroscopy.
References:
[1] W. H. Renninger, P. Kharel, R. O. Behunin and P. T. Rakich, “Bulk crystalline optomechanics,”
Nature Physics 14, 601–607 (2018).
Prerequisites: Electromagnetic theory, electronics and measurement techniques.

The center-of-mass dynamics of a silica sphere (diameter 200 nm) that is trapped at a focus of laser beam is defined by its translational and rotational degrees of freedom. In addition to its center-of-mass degrees of freedom the sphere has also internal degrees of freedom (vibrations), which are analogous to the ringing of a wine glass. The vibrational modes have frequencies Omega m and can be excited by a nonlinear optical process, called stimulated Brillouin scattering [1]. Energy conservation requires Omega m = w1-w2. The output signal will be at a maximum whenever the frequency difference w1 − w2 is resonant with a vibrational frequency Omega m. The objective of this project is to develop a stimulated Raman scattering setup (see figure) and to characterize the vibrational modes (acoustic phonons) of a levitated silica sphere. The work involves microwave electronics, optomechanics, and nonlinear optical spectroscopy.

References: [1] W. H. Renninger, P. Kharel, R. O. Behunin and P. T. Rakich, “Bulk crystalline optomechanics,” Nature Physics 14, 601–607 (2018).

Prerequisites: Electromagnetic theory, electronics and measurement techniques.