terahertz sensing with spoof plasmonic devices oral... · plasmonics: simple process where one can...

Terahertz Sensing with

Spoof Plasmonic Devices

Content1.Introduction of project

2.Methodology 1 and 2

3.Results and Discussion 1 and 2

4.Conclusion

1. Introduction:Current Methods: Gas or chemical sensing are not portable and complex

Plasmonics: Simple process where one can just shine light onto the sample and is portable

Purpose: Push the plasmonic sensing to low frequency such as the terahertz frequency to address the limitations of current methods

Aim: To create the design for the Spoof LSPs and ESPPs

1. IntroductionProblems of current methods:

1. Complex

2. Energy inefficient

3. Not portable

Aims of project:

1. Portable

2. Cost effective

3. Simple

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Overview: The 2D structure consists of an inner cylinder of radius r overlaid with radial grooves of height h=R-r, width a, and periodicity d = 2pi(R/N), where N is the total number of grooves. The number of grooves and radius of the cylinder are chosen to satisfy. The grooves are filled with a dielectric of refractive index ng, and the surrounding medium is air.

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Step 1: Open COMSOL Multiphysics and this page would be seen

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Step 2: Click global definitions and define variables and values

Parameters

R: Large Radius

E: Electric Field of incident wave

S: scattering cross-section of incident wave

r: small radius

d: periodical distance between 2 red circles at the sidea

a: distance between 2 tubes

Hh: R-r

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Step 3: Click structure and build a model

Step 4: Choose the shape of the circle and add and define the parameters

Step 5: Choose the shape of a square and define it

Step 6: Choose the shape of a rectangle and define it (repeat step 4 times)

Step 7: Choose the shape of a square and define it (repeat the step 4 times)

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Step 8: Create the spiral shape and the design will look like this

2.1 Methodology for Spoof Localised surface plasmons (LSPs)Step 10: Det white as matter and grey as air

Step 11: Click EMW and under domain selection all domains and select 5

Step 12: Click settings and solve for scattered field

Step 13: Click settings and solve for scattered field

Step 14: Add mesh

Step 15: Start Simulation

3.1 Results and Discussion for spoof LSPsAfter simulating for 24 hours, the results are as shown below

3.1 Results and Discussion for spoof LSPsAfter simulating for 24 hours, the results are as shown below

2.2 Methodlogy for Effective Surface Plasmon Polaritons (ESPPs)- Making induced ESPPs through dielectric waveguide structures where transverse electric modes are transformed into ESPPs.

- A rectangular waveguide with a cresent shaped dielectric cylinders inserted into the waveguide.

Waveguide structure

Crescent structure

Final structure

4. ConclusionAll in all, materials respond to light at different frequency and a novel design for spoof LSPs and ESPPs has been developed in this project. Furthermore, this method to measure the terahertz sensing of different materials which is better than current methods