Arrays of Ag split-ring resonators coupled to InGaAs single-quantum-well gain

Abstract

We study arrays of silver split-ring resonators operating at around 1.5-µm wavelength coupled to an MBE-grown single 12.7-nm thin InGaAs quantum well separated only 4.8 nm from the wafer surface. The samples are held at liquid-helium temperature and are pumped by intense femtosecond optical pulses at 0.81-µm center wavelength in a pump-probe geometry. We observe much larger relative transmittance changes (up to about 8%) on the split-ring-resonator arrays as compared to the bare quantum well (not more than 1-2%). We also observe a much more rapid temporal decay component of the differential transmittance signal of 15 ps for the case of split-ring resonators coupled to the quantum well compared to the case of the bare quantum well, where we find about 0.7 ns. These observations are ascribed to the evanescent coupling of the split-ring resonators to the quantum-well gain. All experimental results are compared with a recently introduced analytical toy model that accounts for this evanescent coupling, leading to excellent overall qualitative agreement.

Dual-channel spontaneous emission of quantum dots in magnetic metamaterials

“…This is unlike the case of small, highly symmetric metal particles in which PL enhancement is governed by the dipole moment of the nanoparticle 40,44 while higher-order excitations cannot couple to the far field and lead to PL-quenching. Furthermore, in sharp contrast to the previous work on coupling of metamaterials to semiconductor quantum wells 27 , coupling of QDs to different plasmonic modes is not restricted by selection rules imposed by the quantum-well structure. Hence, core-shell QDs are a highly flexible and robust material system that allow for investigating mode competition in QD-metamaterial systems.…”

“…Finally, active metamaterials might also enter new, unexplored areas such as quantum metamaterials [22][23][24] . In recent years, strong efforts have been made to find practical ways of reducing losses in optical metamaterials 21,[25][26][27][28][29] , leading to the first demonstration of a loss-compensated negative-index metamaterial 26 . An important step in controlling the process of loss compensation is the study of coupling of quantum emitters such as quantum dots (QDs) with metamaterials.…”

Past achievements and future challenges in the development of three-dimensional photonic metamaterials

“…Corresponding theory 82,83 has been published as well. Other experiments using semiconductor gain in split-ringresonator metamaterials have only achieved partial loss compensation 84,85 . In principle, under stable steady-state conditions, the FOM can approach infinity at a single wavelength 86,87 .…”

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

“…Most notably, the application of gain media has appeared in the literature. [49][50][51][52][53][54][55][56][57][58][59] There are problems, however, with the employment of gain media in metamaterials as Stockman has pointed out. 196 Notably, full or overcompensation of losses with gain leads to instability that brings the metamaterial into a spaser state.…”

“…While there are designs for isotropic negative index metamaterials (NIMs), 46,47 there exists no experimental 3D isotropic optical NIMs suitable for perfect imaging as envisioned by Pendry due to the constraints of nanofabrication and absorptive losses. 16,48 Fortunately, a number of promising loss compensation methods have appeared, including the employment of gain media, [49][50][51][52][53][54][55][56][57][58][59] geometric tailoring, 60 and plasmon injection. [61][62][63][64][65] Somewhat surprisingly, there is less detailed treatment given in the literature to the practical matter of extracting the image from a near-field superlens than one might expect.…”