2019 Fiscal Year Annual Research Report
Structured complex potentials for designer topological systems and devices in optics
| Project/Area Number |
18F18790
|
|---|
| Research Institution | Institute of Physical and Chemical Research |
|---|
Principal Investigator |
樽茶 清悟 国立研究開発法人理化学研究所, 創発物性科学研究センター, グループディレクター (40302799)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
DEL VALLE INCLAN YAGO BALTASAR 国立研究開発法人理化学研究所, 創発物性科学研究センター, 外国人特別研究員
|
|---|
| Project Period (FY) |
2018-11-09 – 2021-03-31
|
| Keywords | topological / polariton / non-Hermitian |
|---|
| Outline of Annual Research Achievements |
Sample fabrication recipe and process has now been optimised, and we have achieved robust control of the spatial resolution and reproducibility of the bi-layer SiO2 patterns used to create non-Hermitian potentials. Samples may now be rapidly designed and fabricated.
Finalised measurements and simulations on superfluid transport in polariton condensates, specifically the effect of small, non-resonant, pulsed perturbations on a large quasi-CW condensate. Directly measured for the first time, the superfluid speed, in agreement with conservative physics. Characterised dynamics of the condensate depletion, and found a previously unreported depletion wave phenomena. This provides new constraints to the underlying relaxation processes and will be useful for dynamical perturbation in the future.
|
| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Experiments are proceeding well, but development of a fabricated platform for topological and non-Hermitian potentials has been slightly delayed due to the designated plasma etching machine used for removing the SiO2 micropillars not being capable of the processing. We have collaborated with a group in Australia for this step. The virus prevention shutdowns have also delayed the completion of this sample.
We have now refined the process recipe and these issues appear to be solved. We expect to now be able to rapidly fabricate numerous functional samples to satisfy the goals of this research project.
Despite the delays in the sample fabrication, we have completed a related project on the effects on open-dissipation on superfluid dynamics, for which a manuscript is being finalised.
|
| Strategy for Future Research Activity |
The first set of functional samples for the project are expected be ready to measure within 2-4 weeks after the institutions reopen. Two samples will be fabricated and spectroscopic measurements conducted in the short term.
The first focuses on Hermitian properties of the polariton wavefunction, with three goals in order of complexity: a calibration of the trapping and coupling strengths; a demonstration of lattice bandstructures; and the creation of three more complex bandstructures (quasicrystals, higher-order topological edge states, and Landau-levels in polaritonic graphene). The second sample design focuses on non-Hermitian aspects, with two goals: calibrating the non-Hermitian coupling strength and demonstrating the controlled emergence of exceptional points in polaritonic graphene.
|
