k-Space Hyperspectral Imaging by a Birefringent Common-Path Interferometer

Abstract

Fourier-plane microscopy is a powerful tool for measuring the angular optical response of a plethora of materials and photonic devices. Among them, optical microcavities feature distinctive energy-momentum dispersions, crucial for a broad range of fundamental studies and applications. However, measuring the whole momentum space (k-space) with sufficient spectral resolution using standard spectroscopic techniques is challenging, requiring long and alignment-sensitive scans. Here, we introduce a k-space hyperspectral microscope, which uses a common-path birefringent interferometer to image photoluminescent organic microcavities, obtaining an angle-and wavelength-resolved view of the samples in only one measurement. The exceptional combination of angular and spectral resolution of our technique allows us to reconstruct a three-dimensional (3D) map of the cavity dispersion in the energy-momentum space, revealing the polarization-dependent behavior of the resonant cavity modes. Furthermore, we apply our technique for the characterization of a dielectric nanodisk metasurface, evidencing the angular and spectral behavior of its anapole mode. This approach is able to provide a complete optical characterization for materials and devices with nontrivial angle-/wavelength-dependent properties, fundamental for future developments in the fields of topological photonics and optical metamaterials.

Controlling Molecular Photoisomerization in Photonic Cavities through Polariton Funneling

“…MC features a broad electronic absorption centered at approximately 550 nm (Figures c, S1, and S2). When MC is embedded in a resonant cavity, we observe a characteristic splitting of the exciton and photon peaks into upper and lower polariton bands (Figure c), in line with previous reports. ,, To resolve the polariton dispersion, we implement broadband Fourier-plane optical microscopy, − enabling the capture of a full angle-resolved spectrum in a single (1 ms) exposure using low irradiation intensity (Figure S3). Compared to angle-resolved spectroscopy that requires beam- or sample-scanning, our approach crucially reduces light exposure, which would prevent accurate characterization of the dispersion evolution during a light–driven reaction.…”

Ultrafast All-Optical Metasurfaces: Challenges and New Frontiers

“…This allows for retrieving the dispersion relations of the metasurface resonances or the dependence of light−matter interactions on the light momentum (or, equivalently, the angle of incidence, in the most common implementations). 79 • Excitation-frequency-resolved: Complex systems supporting multiple absorption resonances require spectral selectivity over the excitation frequency, while still retaining the ultrafast temporal resolution. Two-dimensional electronic spectroscopy (2DES), which correlates over time excitation and detection frequencies, is the elective tool to dissect correlations, coherences and intricate phenomena.…”