Organic Laser Coupled Microcavity Low Optical Loss
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Solution Overview
Problem
Existing electrically pumped organic laser devices face challenges in achieving low optical loss and high reflectivity at organic-electrode interfaces, limiting their ability to operate efficiently under electrical pumping due to high carrier mobility and optical absorption issues in organic films.
Innovation Solution
A low-loss microcavity organic laser device with a coupled microcavity structure is developed, featuring a substrate, bottom mirror, spacer, coupling mirror, anode, active layer, cathode, and top mirror, with an anode buffer layer, hole-transporting layer, gain zone, electron-transporting layer, and cathode buffer layer, which enhances electron and hole injection efficiency and reduces optical absorption, allowing for high reflectance electrical contacts and efficient electroluminescent emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional waveguide or DFB structures are used in electrically pumped organic laser devices, then the device structure is simpler, but optical loss increases due to the need for thick organic films to achieve high current densities
Solution Approach 1:
The patent changes the fundamental operating parameters by using a microcavity structure with thickness on the order of the optical wavelength rather than thick waveguide structures. This parameter change enables lasing at much lower current densities, directly reducing optical absorption losses in the organic film while accepting increased structural complexity through the microcavity design
Solution Approach 2:
The patent transitions from planar waveguide/DFB structures to a vertically-coupled microcavity structure, adding the dimension of vertical optical confinement. This dimensional change allows the laser to operate with thin organic films by creating strong optical fields in the vertical direction, thereby reducing optical loss without requiring complex lateral confinement structures
2Loss of energy
If microcavity structure with thin organic film is used, then optical loss is reduced, but reflectivity at organic-electrode interfaces must be extremely high (≥97%) which is difficult to achieve
Solution Approach 1:
The patent introduces buffer layers as intermediary structures between the organic active layer and the electrode contacts. These buffer layers serve as mediators that improve carrier injection efficiency while maintaining the optical properties needed for high reflectivity, thus achieving both low optical loss and reliable interface performance without requiring extremely high reflectivity at the direct organic-electrode interface
Solution Approach 2:
The patent employs composite electrode structures combining multiple materials (such as metal layers with buffer layers or transparent conducting oxides) to achieve both high electrical conductivity for carrier injection and high optical reflectivity. This composite approach allows the system to meet both the low optical loss requirement and the high interface reflectivity requirement simultaneously
3Adaptability or versatility
If electrical pumping is used instead of optical pumping, then device integration is improved, but optical loss increases due to lower carrier mobility in organic films
Solution Approach 1:
The patent changes the key parameter of organic film thickness from thick (required for waveguide structures to achieve high current density) to thin (on the order of optical wavelength for microcavity). This parameter change enables electrical pumping to be effective by reducing optical absorption loss to a level that can be compensated by the electrical injection efficiency, while maintaining the integration advantages of electrical pumping
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a high reflectance electrical contact and low loss microcavity structure, enabling surface-emitting laser output under electrical pumping with improved electroluminescent emission efficiency and reduced optical absorption.
Implementation Method 1
electrically pumped organic laser devices
Implementation Method 2
microcavity that are formed by depositing one or multi-layer organic materials between two mirrors
Implementation Method 3
electroluminescent emission efficiency is improved due to the realization of efficient electron-injection and hole-injection
Implementation Method 4
two highly reflective mirrors to construct a high quality factor (high Q) cavity
Data Source
AI summary
Electrically pumped surface emitting organic laser device having a multi-layer of organic materials disposed between a highly reflective microcavity mirror and a highly reflective mirror to thereby form a coupled microcavity. More specifically, the organic laser device includes a substrate; a bottom mirror over the substrate; a layer of spacer over the bottom mirror; a coupling mirror over the spacer layer; an anode over the coupling mirror; an active layer over the anode; a cathode over the active layer; and a top mirror over the cathode. The combination of the electrode and the mirror leads to low optical absorption and highly reflective electrical contacts at organic-electrode interfaces. Electroluminescent emission efficiency is improved due to the realization of efficient electron-injection and hole-injection. A low loss organic laser device with a coupled microcavity structure is realized that can produce surface emitting laser output under electrical pumping.