Integrated Double-Membrane Microspectrometer With Tunable Resonance
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Solution Overview
Problem
Existing optical sensors are bulky, costly, and have a trade-off between resolution and size, limiting their applicability in compact and cost-effective applications such as gas sensing, industrial process monitoring, and medical diagnostics, with prior art achieving limited resolution and spectral range.
Innovation Solution
An integrated double membrane microspectrometer with electromechanically-tunable photonic structures, utilizing a photonic crystal cavity and integrated photocurrent detector, enabling high-resolution spectral measurements through resonance modulation spectroscopy and compressive sensing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete optical elements are used for optical sensing, then resolution and selectivity are improved, but device size and cost increase
Solution Approach 1:
The patent combines multiple discrete optical elements (grating, detector array, optical path) into a single integrated photonic chip. The grating structure, detector elements, and optical pathways are merged into one compact device, achieving high resolution while dramatically reducing device size from conventional bulky instruments to a chip-scale platform.
Solution Approach 2:
The patent employs a nested structure where detector elements are positioned within cavities formed by the grating structure. The grating arms extend into regions containing detector elements, creating a nested arrangement that maximizes the use of space and enables high-resolution measurements in a compact footprint.
2Volume of moving object
If spectrometer size is reduced, then compactness is improved, but resolution deteriorates
Solution Approach 1:
The patent implements local quality by creating regions of different optical path lengths within the grating structure. The grating arms have varying lengths that correspond to different wavelength ranges, allowing each region to be optimized for specific spectral measurements. This enables high resolution across a broad spectral range in a compact device.
Solution Approach 2:
The patent transitions from one-dimensional linear spectrometer designs to two-dimensional planar grating structures on a chip. The grating extends in multiple directions with arms of different lengths, utilizing the planar dimension to achieve wavelength dispersion without requiring long optical paths, thus maintaining high resolution while reducing overall device size.
3Adaptability or versatility
If arrays of spectrometers are produced for hyperspectral imaging, then imaging capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent designs a universal spectrometer chip that can function both as a standalone spectral measurement device and as an element in hyperspectral imaging arrays. The same basic chip structure with integrated grating and detector elements can be replicated and arranged in two-dimensional arrays for imaging applications, simplifying manufacturing compared to traditional approaches requiring different optical components for each function.
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 device offers outstanding resolution and bandwidth in a compact form, suitable for gas sensing, Raman spectroscopy, and motion detection, with sub-picometer wavelength resolution and mass-manufacturability.
Implementation Method 1
both membranes include the same periodic pattern of holes, forming a photonic crystal, with a defect, forming a cavity
Implementation Method 2
the applied voltage alters a spectral position of the resonance, where a photocurrent dependence on the applied voltage outputs a measurement of a spectrum of the illuminating source
Implementation Method 3
the first electrode is connected to an amplifier and the second electrode is connected to a ground to form an integrated photocurrent detector, where the integrated photocurrent detector detects the photocurrent across the first intrinsic semiconductor layer according to the illuminating source directed on the pattern of holes
Data Source
Figure 1~2
Figure 3A
Figure 3B~3D
AI summary
A double membrane microspectrometer is provided that includes a first membrane having a first and second doped semiconductor layers, and a first intrinsic layer is disposed between the first and second layers, where the first intrinsic layer includes an optically absorbing material, a first pattern of through holes are disposed perpendicular through the first membrane having lateral support arms, a second membrane having a third doped layer and a fourth layer is an intrinsic layer or a doped layer, where the second membrane includes a second pattern of through holes, where the first membrane is separated from the second membrane by an insulating bridge layer and is supported above the second membrane by lateral support arms, where an absorption spectrum of the absorbing material is dependent on the separation distance of the membranes, electrodes are disposed on the first layer, the second layer, and the third layer operate the separation.