Threshold reduction by multidimensional photonic confinement in metal-organic microcavities

Abstract

Due to their geometry, optical microcavities allow strong confinement of light between the mirrors and promise single mode operation at lowest possible lasing thresholds. Nevertheless, such devices suffer from losses not only due to parasitic absorption of the active or mirror layers, but especially via outcoupling of leaky and waveguided modes within the active layer.In this work, we present an organic microcavity sandwiched between high quality dielectric distributed Bragg reflectors. A highly conductive silver layer of 40 nm thickness is added next to the active layer, leading to the formation of Tamm-Plasmon-Polaritons (TPP), one replacing the original cavity mode and shifting its resonance to the red, another one emerging from the long-wavelength sideband and moving to the blue. To avoid parasitic absorption introduced by such contacts, the silver layer is structured on the micrometer-scale using photolithography, yielding seperated areas supporting either original cavity mode or red shifted TPP-resonances. This separation leads to a strong spatial trapping of the modes to only their resonant regions on the sample and can in turn be exploited to achieve complete three-dimensional confinement of photons.In elliptic holes produced in the metal layer, we observe the formation of Mathieu-Modes, leading to a reduction of the lasing threshold by six times. Facilitating triangular cuts in the silver layer, highly confined standing modes develop in the system, allowing a precise optimization of the spatial mode extension and reducing the threshold even further down to one order of magnitude below the threshold of an unstructured organic cavity.These results show that the introduction of absorptive metals, needed for the realization of an electrically driven laser, can in turn be harnessed to improve the characteristics of the device.

37‐1: Invited Paper: Effect of Organic Charge Generation Layer on Performance of White OLED Devices

“…However, because the conductivity of N-CGL is higher than that of high PPI pixel structure, the transverse leakage between pixels is more serious, and the device efficiency and product color gamut decrease sharply, which seriously restricts the commercialization of OLED. [8][9][10][11][12][13][14] The application of stacked OLED is that when voltage is applied to the anode of a sub-pixel to make it emit light, the voltage and current on the sub-pixel will not affect other adjacent sub-pixels at all. However, in fact, because of the continuous current between the cathode and the organic functional layer, there may be lateral transmission between adjacent pixels, resulting in the adjacent sub-pixels that should not be lit will also glow faintly.…”

P‐112: Improvement of White OLED Performance by Optical Enhancement Structure

“…The essence of all kinds of phenomena in optical microcavity comes from the confinement effect of environment on photons. Einstein pointed out in 1917 that atoms in excited state can emit photons through spontaneous emission and stimulated emission [8] , so that everyone thinks that spontaneous emission is the intrinsic property of matter, and only by using this spontaneous emission can heat balance be achieved between atoms and vacuum electromagnetic fields. In fact, if we change the mode structure of vacuum electromagnetic field by optical micro-resonance, or even select only a special light mode, the spontaneous emission of excited atoms will occur.…”