Sensors

The sensors industry is always looking to adopt a new platform of sensing that can bring out a more robust, efficient, reliable, and economical solution to general and niche markets.  Advantages of using optical sensors in both intrinsic and extrinsic modes for an array of physical, chemical, and biological parameters are well-addressed and in most cases are favorable to other approaches.   Reversible sensors based on luminescence, fluorescence, absorption, polarization, scattering, and other techniques are prime candidates to be adopted within this technology.  Most traditional optical (photonic)-based sensors require an optical-based setup comprising of sub-assemblies for a light source, a delivery channel (optical fiber), a detector, and a set of optical elements, such as lenses, mirrors, filters, diffraction grating, and splitters to direct, select, and reject different bands of optical wavelengths to be able to efficiently extract the parameter of interest.   As other sub-assemblies for electronics, software and alignment mechanisms are added, the system bulkiness and consequently cost and reliability becomes an obvious issue.  IMS took the lead to provide a practical solution by focusing on the integration of wide bandgap microelectronics devices on a single transparent or opaque substrate. 

A wide spectrum of applications can be exploited using IMS sensors platform.  A clear advantage for using the group III-Nitrides materials is their inherited ability to efficiently handle a spectral range from the UV to IR bands representing a bandwidth of (200-1700) nm and their infamous resistance to operate and withstand elevated harsh environments parameters.  These devices can tolerate high radiation levels and an operating temperature of up to 350 oC.  Besides the gain from miniaturization, ruggedness, and cost savings, this technology can add a new and very significant dimension unseen with other competing technologies.   Simply stated, it is the ability to reconfigure these microstructures so one can selectively program and fine tune specific light bands emitted and/or detected by these structures.  The impact of this feature facilitates the integration of multiple functionality sensors in one small size package.  
 

Chemical and Biomedical Sensors:

Capitalizing on IMS integrated micro sensors platform technology, a single or array of optical sensors can be fabricated to detect or monitor chemical and biomedical analytes within harsh industrial or clinical environments.   Among the wide spectrum of applications, sensors for ultrafine aerosol and collagen detection and characterization were built and tested. With recent developments in the group III-Nitrides materials growth techniques, a hand-held version of these sensors was developed and tested.  Signals controls were implemented using advanced electronic circuitry based on Field Programmable Gate Arrays (FPGA), which permits the integration of Analog-to-Digital Convertors (ADC), amplifiers, logic, acquisition devices, and intelligent analysis system based on Artificial Neural Networks (ANN) into a single portable device. 

Chip-based integrated filterless (no optics) multi-wavelength optoelectronic sensor prototypes have been fabricated and characterized.  The fabrication of the device from concept to prototype is shown in the figures below:

Chip-based optoelectronic sensor concept

Prototype design and fabrication

Packaged chip-based optoelectronic sensor 

Depending on the nature of the analyte and its optical properties, various combinations of optical phenomena, such as fluorescence, absorption, scattering, and reflection can be used for analyte measurements.  Individual analytes signatures can be obtained by using multi-wavelength LEDs and wavelength-selective photodetectors.  Analyte classification using such signatures can be performed by introducing the data into an ANN.

In one application, a collagen fluorescence sensor prototype employs two narrow band light sources at 335 nm and 532 nm as the excitation wavelengths, while the detection wavelengths are at 370 nm ± 10 nm and 560 nm ±10 nm respectively. Results of the collagen concentration detection in solution using 532 nm excitation wavelengths are shown in the figures below:

Collagen fluorescence sensor module with fiber optic waveguides.

Measured fluorescence for collagen concentrations as low as 0.1% W/V

 

 

 

 

 

 

 

 

 

 

 

 

Physical Sensors:

Under construction

 

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