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Multifrequency Gas Sensing using Nanophotonic Infrared Emitting Metamaterials

Primary Investigators:
Josh Caldwell
 
Brief Description of Project:
Nondispersive infrared (NDIR) gas sensing is a common and straightforward technique of monitoring the presence and concentration of ambient gases, such as CO and CO2. In its simplest geometry, an NDIR gas sensor consists of a broadband infrared (IR) emitter and an infrared detector that are separated at opposite ends of an opened highly-reflective chamber by a spectral bandpass filter. Light from the emitter is directed towards the detector and filtered in order to isolate the spectral region corresponding to the IR absorption of the gas molecules of interest. The intensity of the transmitted light through both the filter and gas is then measured by the detector. When trace amounts of the gas enter the chamber, a drop in intensity is read by the detector due to the absorption. In our lab we study methods for confining and manipulating light at the nanoscale, using what are called polaritons to achieve this goal. These polaritons can be used to realize strongly absorbing optical antennas that when heated result in a narrowband and polarized infrared source using thermal emission. 

This project will focus on the design of frequency-tunable, narrow linewidth absorption/emission infrared sources, called Nanophotonic InfraRed Emitting Metamaterials (NIREMs). These NIREM devices can be designed such that their resonant frequency matches the IR absorption of a gas molecule of interest. In past summer projects our group has demonstrated how these NIREMs can be implemented in NDIR gas sensing to eliminate the need for the bandpass filter, therefore providing a cheaper device with higher sensitivity to the gas molecule. The goal of this summer project will be to move to multi-frequency functionality. By combining multiple NIREM devices on the same chip, each designed to target the absorption of a specific gas molecule, multiple gas molecules can be detected on the same platform simultaneously. Further, these multi-frequency NIREM devices can be designed such that they more accurately match the IR signature of a gas molecule, allowing its presence to be detected with greater certainty. This design offers a promising route towards achieving highly-sensitive NDIR sensors, significantly advancing the state of the art and expanding to functionality that is not achievable in conventional NDIR sensing, while also potentially decreasing the energy consumption of the device.

Desired Qualifications:
Some background in optics or spectroscopy a plus. Position requires someone good with their hands and not afraid to set up new experiments.
 
Nature of Supervision:
Student will meet with PI once per week to discuss research progress, will attend a joint group meeting and will have access at other times as needed. Student will be working closely with an 4th year graduate student.
 
A Brief Research Plan (period is for 10 weeks):
In past summer projects our group has demonstrated how these NIREMs can be implemented in NDIR gas sensing to eliminate the need for the bandpass filter, therefore providing a cheaper device with higher sensitivity to the gas molecule. The goal of this summer project will be to move to multi-frequency functionality. By combining multiple NIREM devices on the same chip, each designed to target the absorption of a specific gas molecule, multiple gas molecules can be detected on the same platform simultaneously. Further, these multi-frequency NIREM devices can be designed such that they more accurately match the IR signature of a gas molecule, allowing its presence to be detected with greater certainty. This design offers a promising route towards achieving highly-sensitive NDIR sensors, significantly advancing the state of the art and expanding to functionality that is not achievable in conventional NDIR sensing, while also potentially decreasing the energy consumption of the device.
 
Number of Open Slots: 1
 
Contact Information:
Name: Josh Caldwell
Department: Mechanical Engineering
Email: josh.caldwell@vanderbilt.edu