Quantum Dot Light Modulator for Fast Beam Steering Phase Control
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Solution Overview
Problem
Existing light modulation elements suffer from slow operation response times, increased volume and cost due to mechanical movement, complex circuitry, and limited application due to vibration issues, and require pixel-level control which complicates the process.
Innovation Solution
A light modulation element using a group III-V quantum dot nanostructure with a tunable meta-surface that independently controls gain and phase of light through Mie resonance, allowing for a compact 2D array with optical amplification and phase modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal or MEMS structure is used for light modulation, then light transmission/reflection control is achieved, but operation response time becomes slow (several microseconds or more)
Solution Approach 1:
The patent replaces mechanical movement systems (MEMS) and liquid crystal molecular reorientation with a semiconductor-based optical modulation system using quantum confined Stark effect and plasma dispersion effect. This substitution eliminates slow mechanical/ molecular response mechanisms and achieves faster modulation speeds through electrical field control of refractive index and gain in semiconductor materials.
Solution Approach 2:
The patent changes the fundamental operating parameter from mechanical displacement or molecular orientation to electrical field-induced refractive index change and carrier density modulation in semiconductor. By applying voltage to control the refractive index and gain of semiconductor material, the system achieves rapid response without mechanical inertia or viscous drag limitations.
2Ease of operation
If MEMS structure using mechanical movement is used, then light blocking/reflecting control is achieved, but volume of the light modulation element increases and price increases
Solution Approach 1:
The patent replaces bulky mechanical MEMS structures with planar semiconductor-based optical modulation elements. The semiconductor layer with quantum wells or dots provides light modulation functionality through electrical field control, eliminating the need for mechanical moving parts and reducing device volume significantly while maintaining light control capability.
Solution Approach 2:
The patent extracts the essential light modulation function from complex mechanical MEMS structures and implements it using only the semiconductor optical gain and refractive index modulation properties. This extraction removes unnecessary mechanical components and reduces the device to its minimal functional form factor.
3Measurement precision
If OPA method is used to modulate phase of light, then phase control is achieved, but circuit and element become complicated and process cost increases
Solution Approach 1:
The patent merges phase modulation and gain control functions into a single semiconductor layer structure. By controlling carrier density and electrical field in the quantum well/dot structure, both phase (via refractive index) and amplitude (via optical gain) are modulated simultaneously or independently through the same physical mechanism, eliminating the need for separate OPA circuitry for each pixel.
Solution Approach 2:
The semiconductor optical modulation element serves multiple functions: phase modulation, amplitude modulation, and beam steering, all through electrical field control of the semiconductor material properties. This multi-functionality replaces the specialized single-function components required in OPA systems, simplifying the overall device architecture.
4Volume of stationary object
If metasurface with thickness less than wavelength is used, then compact structure is achieved, but independent control of gain and phase becomes difficult
Solution Approach 1:
The patent changes the control parameters by utilizing carrier density and electrical field as independent tuning knobs for both gain and refractive index in the quantum well/dot structure. This allows independent control of amplitude and phase through separate electrical signals applied to the same thin semiconductor layer, overcoming the limitation of passive metasurfaces.
Solution Approach 2:
The patent introduces dynamic electrical control to the thin semiconductor structure, enabling real-time adjustment of both gain and phase characteristics. The electrical field control allows the system to dynamically switch between different operating states (amplification, attenuation, phase shift) without changing the physical structure, achieving independent control in a compact form.
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 nanostructure enables high output light amplification and phase change with independent control, overcoming size and complexity limitations of existing technologies.
Implementation Method 1
A light modulation element using a group III-V quantum dot nanostructure with a tunable meta-surface that independently controls gain and phase of light through Mie resonance
Implementation Method 2
The nanostructure enables high output light amplification and phase change with independent control, overcoming size and complexity limitations of existing technologies
Data Source
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AI summary
Provided is a light modulation element including a first contact layer, a second contact layer, an active layer provided between the first contact layer and the second contact layer, a first contact plug provided between the first contact layer and the active layer, and a second contact plug provided between the second contact layer and the active layer, wherein a width of at least one of the first contact plug and the second contact plug is less than a width of the active layer.