Propagation length enhancement of surface plasmon polaritons in gold nano-/micro-waveguides by the interference with photonic modes in the surrounding active dielectrics

Abstract

Abstract:In this work, the unique optical properties of surface plasmon polaritons (SPPs), i.e. subwavelength confinement or strong electric field concentration, are exploited to demonstrate the propagation of light signal at 600 nm along distances in the range from 17 to 150 μm for Au nanostripes 500 nm down to 100 nm wide (30 nm of height), respectively, both theoretically and experimentally. A low power laser is coupled into an optical fiber tip that is used to locally excite the photoluminescence of colloidal quantum dots (QDs) dispersed in their surroundings. Emitted light from these QDs is generating the SPPs that propagate along the metal waveguides. Then, the above-referred propagation lengths were directly extracted from this novel experimental technique by studying the intensity of light decoupled at the output edge of the waveguide. Furthermore, an enhancement of the propagation length up to 0.4 mm is measured for the 500-nm-wide metal nanostripe, for which this effect is maximum. For this purpose, a simultaneous excitation of the same QDs dispersed in poly(methyl methacrylate) waveguides integrated with the metal nanostructures is performed by end-fire coupling an excitation laser energy as low as 1 KW/cm 2 . The proposed mechanism to explain such enhancement is a non-linear interference effect between dielectric and plasmonic (super)modes propagating in the metal-dielectric structure, which can be apparently seen as an effective amplification or compensation effect of the gain material (QDs) over the SPPs, as previously reported in literature. The proposed system and the method to create propagating SPPs in metal waveguides can be of interest for the application field of sensors and optical communications at visible wavelengths, among other applications, using plasmonic interconnects to reduce the dimensions of photonic chips.

Interface and Bulk Standing Waves Drive the Coupling of Plasmonic Nanostar Antennas

“…Surprisingly, while the third harmonic does not appear substantially shifted in all three cases, the second harmonic is attenuated to a vanishing point only in the case of the two-spike star. We view the role of the core as an electron reservoir that interacts with the standing wave oscillating along the collinear spikes, resembling the case of a double open-ended waveguide, , with the core being the closed end and the spike tips being the open ends. This view suggests the possibility of the existence of a selection rule that phenomenologically translates into the observation of selectively dampened plasmonic modes in this nanostructure.…”

Energy Attenuation Prediction of Dye-Doped PMMA Microfibers by Backpropagation Neural Network

“…The energy propagating along a straight microfiber weakens quickly with the growth of the propagation distance (L) [1], [3], [22]. The attenuation of light intensity is affected by many factors, such as the incident wavelength [3], [23], [24], diameter [6], [25], [26], and doping concentration [13], [27].…”

Дисперсия Объемных Волн В Структуре "Графен--Диэлектрик--Графен"

“…В последнее время внимание исследователей привлекают металло-диэлектрические планарные структуры, в частности их волноводные свойства [1][2][3]. К одному из таких важных свойств можно отнести наличие у металлов широкой частотной области, в которой диэлектрическая проницаемость отрицательна, что позволяет возбуждать на границах раздела металла с диэлектриками поверхностные плазмон-поляритоны (ПП) [4].…”

“…Волновые характеристики поверхностных и объемных ПП во многом определяются характером дисперсии материальных параметров граничащих сред. Поведение ПП в металлодиэлектрических волноводных структурах и возможность их практического применения достаточно подробно рассматривались в работах [3,[5][6][7]. Однако использование в качестве волноведущего слоя металлических пленок неизбежно приводит к существенным потерям и значительному уменьшению длины пробега ПП.…”