Nowadays, metamaterials application enjoys notoriety in fluid decontamination and pathogen annihilation, which are frequently present in polluted fluids (e.g., water, blood, blood plasma, air or other gases). The depollution effect is largely enhanced by UVC irradiation. The novelty of this contribution comes from the significant increase by packing of the total surface of metamaterials in contact with contaminated fluids. Packed metamaterial samples are subjected to UVC irradiation, with expected advantages for implant sterilization and long-term prevention of nosocomial infections over large clinical areas. The novel aspect of the investigation consists of a combination of big and small elements of the metamaterial to optimize the above effects connected with fluids and irradiation. The big elements allow the radiation to penetrate deep inside the fluid, and the small elements optimally disperse this radiation toward deeper regions of the metamaterial. A packing scheme of smaller, in-between large metamaterial spheres and fibres is proposed for promoting enhanced depollution against pathogen agents. It is demonstrated that the total surface of metamaterials in contact with contaminated fluids/surface is significantly increased as a result of packing. This opens, in our opinion, new auspicious perspectives in the construction of novel equipment with high sensibility in the detection and decontamination of microorganisms.

The restoration of the initial state in the Raman interaction of the two atoms with the quantified pump and Stokes (anti-Stokes) cavity modes is analytically obtained. For this the su (2) symmetry representation of the bimodal field and a system of two atoms in scattering interaction is proposed for the simplification of the problem. Using the proprieties of the generators su (2) algebra the exact non-stationary solution of the system of two atoms in interaction with the bimodal field is found, taking into consideration the initial disentangled state between the atomic and field superposition. It is demonstrated that after this collapse and revivals of the inversion of flying atoms in the processes of absorption and emission of the photons from Stokes and pump modes the system atoms and field becomes entangled. The conditions of the restoration of the initial state of the atom-field system were established as a function of the flying time through the resonator possible. A set of discrete flying time intervals for the restoration of the initial disentangled state was found.

This chapter introduces an optical framework for the generation of molecular superstructures from tertiary components through Raman-induced interactions with a bimodal cavity field. A nonlinear model is developed based on cooperative processes analogous to multiple Raman scattering and their integration with biomolecular assemblies. Particular attention is given to phase transitions leading to the formation of supramolecular structures, where induced Raman excitation enables the stabilization of multimeric states such as dimers, trimers, tetramers, and pentamers. The proposed master equation describes the synthesis and stabilization of such structures under Raman excitation. Importantly, the model can also be applied inversely, where large molecular aggregates are dissociated into smaller components via induced multiple Raman scattering. This dual mechanism provides a theoretical basis for designing highly efficient optical metamaterials with potential applications in advanced decontamination technologies. To illustrate the applicability, experimental investigations were performed using yeast fungi as a surrogate for more sensitive pathogens (viruses and bacteria). The results revealed two distinct decontamination regimes under nanosecond-pulsed ultraviolet C radiation, consistent with the predictions of the multiple Raman dimerization model. These findings highlight the potential of Raman-driven cooperative processes in both molecular synthesis and selective pathogen inactivation.