Space Apps Challenge 2018

Martian atmosphere is known for it's dust storms as they frequently occurs. Monitoring the concentrations of these dust particles in a portable way plays a vital role to the human explorations on mars. By keeping this in view, we have designed a portable sensor In this proposal, we take the advantage of these polymer-based photonics to design a system which can effectively measure the aerosol/dust particles present in the Martian atmosphere. Polymer photonics were chosen as they promises the low cost fabrication and reliable functionality.

1. Distributed feedback laser (DFB) made of photonic crystal which acts as a source.
2. Microring resonators made of SU-8 polymers on the silicon substrate used for sensing aerosols/dust.
3. Suspended SU-8 waveguides which are used for information transfer with low propagation losses.
4. Photo-Detectors which are used for sensing of output light.

Explanation:

1. Photonic crystal laser (Source):

The fabrication of the laser is obtained by the dynamic self-assembly as this can be achieved by integration of colloidal assembly. The tuning of laser wavelength can be possible by varying the position of the photonic band edge. This wavelength sensitivity could be enhanced by chemically anchoring surface functional groups to the constituent nano-particles to make the laser into a molecule discriminating chemical or biological sensor.

2. Suspended SU-8 Waveguides:

The low refractive index of polymer materials leads to low light confinement and substrate leakages. So, in order to eliminate the substrate leakage, the waveguides made of SU-8 polymer has made suspended so that the waveguide is in contact with the air thus providing loss less transmission.

3. Microring Resonators:

Microring resonators are widely used for sensing, filtering and also for optical storage purposes. These resonators work on the principle of resonant frequency. Evanescent fields are created as a byproduct for total internal reflections which permeate within λ distance outside the diameter of the ring. By taking the advantage of these evanescent waves, the sensing of aerosol particles can be possible. The confinement of light in waveguide and the coupling to the ring resonator is due to fact of having different refractive indices. The ring resonator couples specific wavelengths of light waves in resonance. Microring resonators are separated and provided with a pair of photo-detectors one at the reference waveguide (bottom) and other at the output of microring resonator (top) . The reference waveguide’s photo-detector correlates the light intensity with that of main waveguide photo-detector and if intensity matches then it confirms that no binding event occurred at resonator thus makes a note that no aerosols are being detected.

Click here to find the simulation results of our project:

https://drive.google.com/file/d/0Bz-wJOha6g-5OVNxLTJXbnpLX2VjbVNWdURMOUpEbE90RUVN/view?usp=drivesdk

Click here to find the detailed picture and step by step working of our project:

https://drive.google.com/file/d/1En06XStUowGgiLTBr2O6typ6jzRXDibR/view?usp=drivesdk

We analysed NASA Analyst's notebook- Curiosity mastcam ( Sol 1670 cam: L0) to see how Martian atmosphere looks completely with dust.

Team members:

Sandeep Battula

Santosh Kumar Panda

Shanmukh Chappati