Prediction of hyperbolic exciton-polaritons in monolayer black phosphorus

Hyperbolic polaritons exhibit large photonic density of states and can be collimated in certain propagation directions. The majority of hyperbolic polaritons are sustained in man-made metamaterials. However, natural-occurring hyperbolic materials also exist. Particularly, natural in-plane hyperbolic polaritons in layered materials have been demonstrated in MoO3 and WTe2, which are based on phonon and plasmon resonances respectively. Here, by determining the anisotropic optical conductivity (dielectric function) through optical spectroscopy, we predict that monolayer black phosphorus naturally hosts hyperbolic exciton-polaritons due to the pronounced in-plane anisotropy and strong exciton resonances. We simultaneously observe a strong and sharp ground state exciton peak and weaker excited states in high quality monolayer samples in the reflection spectrum, which enables us to determine the exciton binding energy of ~452 meV. Our work provides another appealing platform for the in-plane natural hyperbolic polaritons, which is based on excitons rather than phonons or plasmons.

Hyperbolic dispersion metamaterials and metasurfaces

In recent years a wide interest has been spurred by the inverse design of artificial materials for nano-biophotonic applications. In particular, the extreme optical properties of artificial hyperbolic dispersion nanomaterials allowed to access new physical effects and mechanisms. The unbound isofrequency surfaces of hyperbolic metamaterials and metasurfaces allow to access virtually infinite photonic density of states, ultrahigh confinement of electromagnetic fields and anomalous wave propagation. Here, we report the most relevant physical properties of different hyperbolic dispersion material geometries and how they allow to control light-matter interaction at the single nanometer scale, in biological matter.

Spectroscopic Analysis of Fluorescent Proteins Infiltrated into Photonic Crystals-=SUP=-*-=/SUP=-

Spectral properties of enhanced-green uorescent protein and monomeric red uorescent protein in porous photonic structures have been studied. The uorescent proteins were successfully inЛtrated into porous silicon photonic structures with dirent positions of the photonic band gap in visible spectral range. The intensity of uorescence is enhanced in the spectral regions of high photonic density of states. The possibility to control the uorescence spectra by the structure with the photonic band gap is demonstrated. Keywords: photonic crystals, porous silicon, uorescent proteins, photonic band gap.

Photonic hypercrystals for control of light–matter interactions

Photonic crystals (PCs) have emerged as one of the most widely used platforms for controlling light–matter interaction in solid-state systems. They rely on Bragg scattering from wavelength-sized periodic modulation in the dielectric environment for manipulating the electromagnetic field. A complementary approach to manipulate light–matter interaction is offered by artificial media known as metamaterials that rely on the average response of deep-subwavelength unit cells. Here we demonstrate a class of artificial photonic media termed “photonic hypercrystals” (PHCs) that combine the large broadband photonic density of states provided by hyperbolic metamaterials with the light-scattering efficiency of PCs. Enhanced radiative rate (20×) and light outcoupling (100×) from PHCs embedded with quantum dots is observed. Such designer photonic media with complete control over the optical properties provide a platform for broadband control of light–matter interaction.