Periodic Reporting for period 2 - ARQADIA (Artificial quantum materials with photons: many-body physics and topology)
Berichtszeitraum: 2022-07-01 bis 2023-12-31
The ARQADIA project finds its inspiration in the physics of condensed matter and particularly in so-called "quantum materials". Quantum materials have very special properties (superconductivity, quantum magnetism, fractional quantum Hall effect) that cannot be described simply by models involving only one particle (atom or electron) at a time, but which require considering the interactions between a large number of particles. Within ARQADIA project we build, using light, synthetic quantum materials where such collective behaviors occur. The goal is twofold: probing these artificial materials to help understanding complex phenomena by probing them in well-controlled systems, and using their collective response as a potential resource applicable to quantum technologies.
In order to generate spatial and temporal quantum correlations in photonic materials, strong interactions between the photonic excitations are required. This represents an outstanding challenge for solid-state quantum optics. The ambition of ARQADIA is to tackle this challenge by manufacturing a new generation of synthetic quantum materials using state-of-the-art nanatechnology processes within the C2N clean room. The devices are made of arrays of "light traps", micrometer-sized cavities defined by two semiconductor mirrors, where light can be confined and manipulated. The coupling between light and electronic excitations in these structures leads to the formation of hybrid light-matter particles (called "polaritons") that behave like interacting photons. By careful engineering of the device properties and geometry, we have created new polaritonic devices with non trivial band topology, and are currently working on imprinting quantum correlations onto the photons escaping the material.
In order to generate spatial and temporal quantum correlations in photonic materials, strong interactions between the photonic excitations are required. This represents an outstanding challenge for solid-state quantum optics. The ambition of ARQADIA is to tackle this challenge by manufacturing a new generation of synthetic quantum materials using state-of-the-art nanatechnology processes within the C2N clean room. The devices are made of arrays of "light traps", micrometer-sized cavities defined by two semiconductor mirrors, where light can be confined and manipulated. The coupling between light and electronic excitations in these structures leads to the formation of hybrid light-matter particles (called "polaritons") that behave like interacting photons. By careful engineering of the device properties and geometry, we have created new polaritonic devices with non trivial band topology, and are currently working on imprinting quantum correlations onto the photons escaping the material.
Over the first 30 Months of the project, research efforts have led to the following progress:
Work Package 1- New sample structures have been developed within the C2N clean room with optimized properties in terms of reducing the residual absorption in the materials, improving the sample homogeneity, and also providing new functionalities to our devices. The technological processes and the samples optical quality are showing constant improvement.
Work Package 2- We have developed a novel spectroscopic method to precisely measure the polariton-polariton interaction constant, based on a two-color excitation scheme. We have characterized the non-linear response of polariton microcavities with various shapes and sizes, and found the optimal samples in terms of strength of the nonlinearity normalized to the polariton linewidth. Our two-photon nonlinear spectrocopy technique can applied to a large variety of semiconductor materials, and provide valuable information regarding the nonlinearity of such materials.
Work Package 3- We have developed an eigenfunction reconstruction method to experimentally measure the photonic eigenstates of a polariton lattice, and then access to the topological properties of the lattice. We tested the method on a two-band system using honeycomb lattices manufactured at C2N. In parallel, we have developed new cavity structures that exhibit a large spin-orbit coupling (energy splitting between the polarization modes). Under an external magnetic field, we observe first signatures of the opening of a topological gap around the Dirac cones, as expected for a polariton Chern insulator.
Work Package 1- New sample structures have been developed within the C2N clean room with optimized properties in terms of reducing the residual absorption in the materials, improving the sample homogeneity, and also providing new functionalities to our devices. The technological processes and the samples optical quality are showing constant improvement.
Work Package 2- We have developed a novel spectroscopic method to precisely measure the polariton-polariton interaction constant, based on a two-color excitation scheme. We have characterized the non-linear response of polariton microcavities with various shapes and sizes, and found the optimal samples in terms of strength of the nonlinearity normalized to the polariton linewidth. Our two-photon nonlinear spectrocopy technique can applied to a large variety of semiconductor materials, and provide valuable information regarding the nonlinearity of such materials.
Work Package 3- We have developed an eigenfunction reconstruction method to experimentally measure the photonic eigenstates of a polariton lattice, and then access to the topological properties of the lattice. We tested the method on a two-band system using honeycomb lattices manufactured at C2N. In parallel, we have developed new cavity structures that exhibit a large spin-orbit coupling (energy splitting between the polarization modes). Under an external magnetic field, we observe first signatures of the opening of a topological gap around the Dirac cones, as expected for a polariton Chern insulator.
Looking forward to the next steps, we expect the next 30 months of the project to yield even more progress beyond the state of the art, in terms of the new sample structures we are currently developing, but also in our search for quantum correlations in microcavities and in the physics of polariton topological insulators:
Work Package 1- We are currently developing electrically contacted samples with the aim of using external electric fields as an extra knob to control polaritons. This will enable us to polarize excitons with the aim of tuning exciton-exciton interactions, as well as realizing an electrical tunable gauge field for polaritons.
Work Package 2- In the upcoming months, we will use our superconducting nanowire single photon detectors to measure quantum correlations in the train of photons emitted through a single microcavity. We will use both our new two-color excitation scheme as well as electrically contacted samples to enhance the temporal correlations. We will then implement small lattices, and search for signatures of both temporal but also spatial correlations.
Work Package 3- Within the next few months, we will use our novel eigenfunction spectroscopy technique to characterize the physical properties of topological lattices. We have already manufactured lattices to implement a polariton Chern insulator, where we will measure the bulk topological invariants for these lattices, and evidence the bulk-edge correspondence at the interface between lattices of different topology. Increasing the excitation power, we will finally investigate nonlinear physics (lasing, two-color excitation) in such topological lattices.
Work Package 1- We are currently developing electrically contacted samples with the aim of using external electric fields as an extra knob to control polaritons. This will enable us to polarize excitons with the aim of tuning exciton-exciton interactions, as well as realizing an electrical tunable gauge field for polaritons.
Work Package 2- In the upcoming months, we will use our superconducting nanowire single photon detectors to measure quantum correlations in the train of photons emitted through a single microcavity. We will use both our new two-color excitation scheme as well as electrically contacted samples to enhance the temporal correlations. We will then implement small lattices, and search for signatures of both temporal but also spatial correlations.
Work Package 3- Within the next few months, we will use our novel eigenfunction spectroscopy technique to characterize the physical properties of topological lattices. We have already manufactured lattices to implement a polariton Chern insulator, where we will measure the bulk topological invariants for these lattices, and evidence the bulk-edge correspondence at the interface between lattices of different topology. Increasing the excitation power, we will finally investigate nonlinear physics (lasing, two-color excitation) in such topological lattices.