Hybridized/coupled multiple resonances in nacre

Abstract

We report that nacre (also known as mother-of-pearl), a wondrous nanocomposite found in nature, is a rich photonic nanomaterial allowing the experimental realization of collective excitation and light amplification via coupled states. Localized modes in three-dimensional complex media are typically isolated in frequency and space. However, multiple local resonances can be hybridized in multilayered nanostructures of nacre so that the effective cavity size for efficient disordered resonators is scaled up. Localized modes in hybridized states in nacre are overlapped in frequency with similar shapes in space, thus being collectively excited and synergistically amplified. These hybridized states boost light amplification, leading to stable and regular multimode lasing at low excitation energy. The simplicity of ameliorating disordered resonators by mimicking nacre can further serve as platforms for developing costeffective photonic systems and provide materials for fundamental research on complex media.

Ultrafast hot-electron induced quenching of Tb 4f magnetic order

“…According to our large error bars of ±200 fs for the experimental onset of sample 3 (300 fs), the contribution of non-thermal hot-electrons to the onset cannot be identified. In summary, considering the results from sample 3, we clearly evidence an efficient demagnetization by thermal hot-electrons as expected from Choi et al [40]. The signature obtained through the demagnetization characteristic times τ allows discriminating from the non-thermal hot-electrons contribution.…”

“…However, a quantitative estimation of the energies injected into the CoTb alloy for sample 2 and 3 is difficult. The energy transported by the hot-electrons dependent on the material and on the interfaces present along the trajectory of the electrons [40]. The presence of additional interfaces in sample 3 (Cu/Pt, Pt/Cu and Cu/CoTb) may however qualitatively explain the reduction of the demagnetization amplitude compared to sample 2 (Cu/CoTb) (sample 3: q~36% and sample 2: q~52%).…”

“…In order to confirm the possibility to induce ultrafast demagnetization in the Tb 4f sublattice by using thermal hot-electrons as proposed by Choi et al [40] we performed the pump-probe experiment with sample 3. To compare the efficiency of demagnetization induced by nonthermal or thermal hot-electrons we have performed the measurements using the same Co 74 Tb 26 alloy but with a specifically designed capping (sample 3).…”

Excitation of multiple resonances in 1D Anderson localized systems for efficient light amplification

“…Necklace states are often considered nonlocalized states, while dominating the transmission statistics due to relatively broad spectral bandwidths [3]. Recently, the concept of necklace states has been extended to include superposition of quasi-modes with several narrow peaks in transmission spectra [4][5][6][7][8]. Such hybridized states are also called extended quasi-modes or short necklace states.…”

2-D PSTD Simulation of focusing monochromatic light through a macroscopic scattering medium via optical phase conjugation

“…A CW plane wave (wavelength λ = 1 μm) with a cross-sectional width of 5 μm is generated at the center of the simulation. The scattering medium consists of 22,222 non-absorbing, randomly-positioned, 5-μm-diameter dielectric cylinders closely-packed (minimum edge-toedge spacing of 0.5 μm) within a cylindrical region with a diameter of 1160 μm; the scattering mean free path is 6.86 μm, the optical thickness is 169, and the strength of disorder (morphological disorder [22]) is 0.0619. A fully surrounding, CW wavefront converging upon the scattering medium is shown in Fig.…”