1. Metal-insulator-metal metamaterial absorbers consisting of proximity-coupled resonators with the control of the fundamental and the second-order frequencies Authors: Kota Ito, Hiroshi Toshiyoshi, and Hideo Iizuka As Presented by: Jonathan Lee

2. Impact Second order mode presence can lead to: Poor signal to noise ratio (detection absorbing element) Poor output power efficiency (selective thermal emitter) T = 500 K

3. Goal of Design Metamaterial: Planar SRR film Use magnetic ordering to influence second order mode Several descriptions may apply: Localized surface plasmon resonance Magnetic resonance Impedance matching to free space Standing-wave resonance (periodic material) Interference between neighboring metal layers Micro/nanoscale patch antennae

4. Geometry ParameterValue [µm] W1.4 S0 - 1.0 P2.0 G0.05 – 0.5 t10.100 t20.250 t30.100 P-polarization Electric Field vector along x Magnetic Field along y

5. Fabrication Sputtering Aluminum 100 nm Amorphous Silicon 250 nm Aluminum 100 nm Electron beam lithography (EBL) Reactive Ion Etching

6. Measurement FT-IR with VeeMax II PIKE accessory

7. Resonances- Square array First Order Mode Available at normal incidence Second Order Mode

8. Resonances- Square array Simulation data from CST MWS Employs Drude Model Aluminum First Order Mode f 1 Second Order Mode ~2 f 1 θ = 60 ᵒ Normalized Magnetic Field Intensity

9. Resonances- Shifted array First Order Mode Second Order Mode Shifted from 2f 1 θ = 60 ᵒ Normalized Magnetic Field Intensity

10. Resonances- Shifted array First Order Mode Available at normal incidence Second Order Mode Shifted from 2f 1

11. Resonance Control Second Order Mode Parameter sensitivity: θ = 60 ᵒ Gap - Proximity Spacing

12. Resonance Control Shift = 700 nm Mode Splitting

13. Experimental Results Shift : 1 µm

14. Experimental Results Shift : 0.7 µm

15. Conclusions Magnetic Ordering can be used to influence second order modes Quickly becomes complicated Can lead to mode splitting Methods used infer polarization specific results Second orders pushed to higher frequency (shorter free space wavelength) CST simulations verified by experiment Future investigations: Determine the source of the split modes