METAMATERIALS

The science of invisibility

1. METAMATERIALS SOUMEN GIRI ROLL NO.- 16MS6019 Materials Science centre IIT KHARAGPUR

2. What is a metamaterial ? Metamaterials are made from assemblies of multiple individual elements fashioned from conventional microscopic materials such as metals or plastics, but the materials are usually arranged in periodic patterns.

3. ME T A M A TERIAL B A C K G R O U ND Do not depend upon chemical composition D ep e n d o n th e g e o m e t r y o f th e s t r ucture un i ts. M e t a m a t erials a r e a r t i f i cial e ng i n e e red c o m p o si t e s t r uctur e s. N o t c o m m o n l y f o un d i n na tur e .

4. B A C K G R O U N D 𝜀 ,                 

5. Refractive Index The refractive index, n, of a medium is defined as the ratio of the speed, C , of a wave phenomenon such as light or sound in a reference medium to the phase Velocity Vp , of the wave in the medium. n = C / Vp =  r  r

6. NE G A TIVE R EF R A CTI VE I N D E X How to ac h ieve n e g a t ive r e f r ac t i ve index? n   r  r Negative refractive index can be achieved when (  r and  r ) are negative = = -1

7. DNG m edium DPS m edium E E S S H H Left handed medium and right handed medium

8. Negative refractive index Calculated ra y - tracing i m a g e of a m etal rod in an e m pty drin k ing g lass. Sa m e scener y , but the g lass is f illed w ith nor m al w ate r , n  1 . 3 , leading to ordinary re f raction. The w ater is replaced by “ w ater” w ith a f ictit i ous re f racti v e index of n   1 . 3

9. E k H Dou b le N e gat i v e Ma t e r ial Left h an d ed Ma t e r ial S Other names Negative refractive index material

10. MANUFACTURING Upto today metamaterials have mostly been manufractured by the technology electron beam lithography. Thease technique have the disadvantage of being quite expansive and slow and obtaining large areas. Material science and technologies currently under investigation to fabricate metamaterials are self assembly.

11. At microwave frequencies, the first real invisibility cloak was realized in 2006. However, only a very small object was imperfectly hidden. In 2007, one researcher stated that for metamaterial applications to be realized, several goals must be achieved. GOAL OF DEVELOPMENT

12. Application of Metamaterials Metamaterial antenna Cloaking device Superlens Invisible Submarines Photonics OR opto-electronics Create the oft-discussed, Invisible Man Perfect Absorber of light Ultra high capacity storage devices etc.

13. Metamaterial antenna Metamaterial antennas are a class of antennas which use metamaterials to increase performance of miniaturized (electrically small) antenna systems. Metamaterial antennas radiate as much as 95 percent of an input radio signal. Experimentally metamaterial antennas are as small as one-fiftieth of a wavelength and could have further decrease in size. Some applications for metamaterial antennas are wireless communications, space communication, satellites etc .

14. Metamaterial cloaking Metamaterial cloaking is the usage of materials in an invisibility cloak. Metamaterials direct and control the propagation and transmission of specified paths of the light spectrum and demonstrate the potential to render an object seemingly invisible .

15. Superlens A practical superlens is a lens which uses metamaterials to go beyond the diffraction limit. The diffraction limit is a feature of convectional lenses and microscopes that limits the fineness of their resolution. Many lens designs have been proposed that go beyond the diffraction limit in some way but there are constraints and obstacles involved in realizing each of them.

16. Future Work Optimize process Create more complicated 3D structures Characterize 3D structure properties Explore new thickness and exposure times

17. REFERENCES https:// en.wikipedia.org/wiki/Metamaterial Nanostructured Metamaterials, By Anne F.de Baas