Skip to main content

Light-driven atomic dynamics in solids and liquids – from fundamentals of optics to engineering of novel photonics technologies

Periodic Reporting for period 2 - DynaLight (Light-driven atomic dynamics in solids and liquids – from fundamentals of optics to engineering of novel photonics technologies)

Reporting period: 2020-06-01 to 2021-05-31

Light propagating in a non-dispersive medium is accompanied by a mass density wave of atoms set in motion by the optical force of the field itself. This prediction of the recently introduced mass-polariton theory of light is contrary to previous theories, which assume that atoms are fixed to their equilibrium positions when light propagates in the medium. Building on the success of the mass-polariton theory of light, we applied the theory to develop new experimental setups with the aim to study optical forces and to eventually discover the atomic mass density wave generated by light in solids and liquids. In the project, we also developed the theory further for the detailed position and time dependent description of light in a wide range of dispersive materials varying from glasses to metamaterials. We also studied how this new optical effect could be used to improve existing photonics technologies and to eventually engineer new photonic devices. The project provided the first quantitative measurement of optical forces of light propagating inside a solid material, but the even more challenging experimental observation of the atomic mass density wave effect had to be left for future works since it remained below the noise level of the experiments carried out in the project. In addition, we experimentally investigated the recently observed optical liquid jetting phenomenon in hollow optical fibers, demonstrating its applicability in the precise control of small amounts of liquids. This technique has potential applications in drug delivery and release, localized deposition of novel materials on a substrate, and hyper-fine printings.
We have generalized the mass-polariton theory and the related optomechanical continuum dynamics simulations for liquids and gases by deriving equations, which show that the mass density wave phenomenon is universal and is not notably different in liquids and gases compared to solids for which the theory was originally derived. The results fundamentally improve our understanding of dynamical phenomena in condensed media under the influence of the optical field and put the continuum dynamics simulations in the framework of the special theory of relativity by explaining how the transferred mass of the mass density wave is related to the principle of relativity. In the project, we also developed the theory further for the detailed position and time dependent description of light in a wide range of dispersive materials varying from glasses to metamaterials.

We have simulated and experimentally studied the coupled field-medium dynamics related to the liquid jetting phenomenon in hollow optical fibers. In addition to the mass density waves and sound waves, this has increased our understanding of the optical heating effect, thermoelastic waves, and thermoviscoelastic waves. These studies have also supported the design of the setups for the verification of the atomic mass density wave effect. In particular, the optical heating effect has been found to dominate over the optical force in the liquid jetting phenomenon. Further thermal imaging experiments were needed to verify this prediction. Despite the presence of the thermal effect, the project demonstrated the wide applicability of the liquid jetting phenomenon in the precise control of small amounts of liquids

We have simulated the atomic mass density wave effect in several setup geometries and realized an experiment for quantitative measurement of forces at the end of an optical fiber that is a step toward the direct experimental verification of the atomic mass density wave effect. We have also demonstrated an accurate free-space radiation pressure sensor setup as a side effect of this research. The project provided the first quantitative measurement of optical forces of light propagating inside a solid material, but the even more challenging experimental observation of the atomic mass density wave effect had to be left for future works since it remained below the noise level of the experiments carried out in the project. In addition, we have participated in the analysis of the experimental data on the measurements of optical forces at free air-liquid interfaces provided by our collaborators.

This far, the project has led to 2 published journal papers and 2 conference proceedings papers, in addition to which 6 papers are under peer review.
Achieving the goals of the proposed research has a fundamental impact on the understanding of the optical surface and volume forces and the propagation of light in solids, liquids, and gases. The project provided a unique opportunity to pioneer the field of light-driven material dynamics and to design novel photonic device concepts utilizing the optical forces and the related atomic mass density wave effect.
Setup for the measurement of radiation pressure using a macroscopic mechanical oscillator