Quantum Dot Light Modulator With Refractive Index Change Layer
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Solution Overview
Problem
Existing optical modulators have slow operation response times due to their driving methods, limiting their ability to quickly modulate light characteristics such as transmission, reflection, phase, amplitude, polarization, intensity, and path.
Innovation Solution
A quantum dot (QD) light modulator is developed, incorporating a refractive index change layer with a carrier density change area adjacent to the QD-containing layer, and a nano-antenna structure, which allows for rapid modulation of light-emission characteristics by changing the refractive index in response to electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional optical modulators (liquid crystal or MEMS) are used, then optical modulation function is achieved, but operation response time is slow (over several microseconds)
Solution Approach 1:
The patent replaces mechanical movement-based modulation (MEMS) or molecular reorientation-based modulation (liquid crystal) with a quantum dot-based optical modulation system. The quantum dots modulate light through electrical control of carrier density, eliminating slow mechanical or molecular movement and achieving sub-nanosecond response times.
Solution Approach 2:
The patent changes the fundamental operating parameter from mechanical displacement or molecular orientation to quantum dot carrier density. By controlling the carrier density in quantum dots through electrical signals, the refractive index and optical properties are dynamically adjusted, enabling fast modulation without mechanical movement.
2Speed
If quantum dot layer is added for fast modulation, then operation speed is improved, but input/output coupling characteristics may deteriorate
Solution Approach 1:
The patent introduces a refractive index change layer as an intermediary between the quantum dot layer and the external environment. This layer compensates for the refractive index mismatch caused by the quantum dot layer, improving light coupling efficiency while preserving the fast modulation capability of the quantum dots.
Solution Approach 2:
The patent creates a composite structure combining quantum dot layer, refractive index change layer, and reflector. This composite design leverages the fast modulation property of quantum dots while using the refractive index change layer to optimize optical coupling, achieving both speed and reliability.
3Reliability
If refractive index change layer is introduced to improve coupling, then input/output characteristics are improved, but device structure becomes more complex
Solution Approach 1:
The refractive index change layer serves multiple functions simultaneously: it improves optical coupling between layers, enables electrical control of refractive index for modulation, and works with both quantum dot layers and reflectors. This multi-functionality reduces the need for additional specialized components, managing complexity while achieving reliable coupling.
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 QD light modulator achieves fast optical modulation and improved input/output coupling characteristics, enabling efficient control of light properties with high speed and precision.
Implementation Method 1
a refractive index change layer with a carrier density change area adjacent to the QD-containing layer, and a nano-antenna structure, which allows for rapid modulation of light-emission characteristics by changing the refractive index in response to electrical signals
Implementation Method 2
a QD-containing layer including a plurality of QDs having light-emission characteristics
Implementation Method 3
a nano-antenna structure, which allows for rapid modulation of light-emission characteristics
Implementation Method 4
a reflector arranged facing the QD-containing layer
Data Source
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AI summary
Provided is a quantum dot (QD) light modulator and an apparatus including the QD light modulator. The QD light modulator may include a QD-containing layer including QDs having light-emission characteristics, a refractive index change layer arranged adjacent to the QD-containing layer, and a reflector arranged facing the QD-containing layer. The refractive index change layer may include a carrier density change area in which a carrier density changes, and the carrier density change area may be arranged adjacent to the QD-containing layer. The light-emission characteristics of the QD-containing layer may be modulated according to a change in a property of the refractive index change layer. The QD light modulator may further include a nano-antenna structure arranged on the QD-containing layer.