Making visible things invisible

FOUR LENS CLOAKING DEVICE

Presented by:NAILA FAZLUR RAHMAN

(1604-12-739-011)

OVERVIEW INTRODUCTION WHAT IS CLOAKING? HOW IT WORKS OPERATION APPLICATIONS LIMITATIONS EMERGING TECHNOLOGY CONCLUSION

• IS INVISIBILITY POSSIBLE?

INTRODUCTION

A cloak of invisibility is a fictional theme and a device under some scientific inquiry.

The cloak is capable of hiding three-dimensional objects three to four orders of magnitudes larger than optical wavelengths, and therefore, it satisfies a layman's definition of an invisibility cloak: namely, the cloaking effect can be directly observed without the help of microscopes

Ideally, if we make it real it would work exactly like Harry Potter's invisibility cloak.

WHAT IS CLOAKING?

Cloaking is a revolutionary technology for making visible things/persons invisible by using either artificial “meta-materials” or invisibility cloak system. Invisibility is the state of an object that cannot be seen., Invisibility is often considered to be the supreme form of camouflage.

TYPES Invisibility by cloaking can be performed in many ways

i. By using meta-materials ii. Invisible clock system of image projectioniii. Four lens cloaking device using off the shelf optics

BY USING METAMATERIALS:To make visible things “invisible” we need to consider the law of reflection of light property, which is obtained by metamaterials

 ⅱ. INVISIBILITY CLOAK SYSTEM OF IMAGE PROJECTION

This is generally used for making visible stationary objects / buildings invisible.

This system utilizes a high efficiency VIDEO CAMERA , COMPUTER PROCESSER , IMAGE PROJECTOR

ROCHESTER CLOAK First 3D visible light invisibility cloak Developed at the University of Rochester in NY Creates “regions of invisibility” that can completely hide objects. Uses refraction through a 4 lens system.

ROCHESTER CLOAK SETUP

Two pairs of convex lenses Pairs having focal lengths f1 and f2

Set up in straight line f2 lenses in middle, f1 on outside distance between f1 and f2 lenses on ends

d1=d3=f1+f2 distance between f2 lenses in middle

d2=2f2(f1+f2)(f1-f2)

HOW IT WORKS?

As light reflects off of the background, it refracts as it passes through the lenses creating “cloaked regions”.

When an object is placed inside of a cloaked region, light from the background passes around object causing the background to be visible, rather than the object!

APPLICATIONS

Due to limitation on size ,still its not possible to make a cloak device for operating wavelength in visible band

Current devices work only for one wavelength but visible light has many wavelength

It is a slow process The observer needs to look through the mirror

LIMITATIONS

EMERGING TECHNOLOGY

‘INFINITY TOWER’ an “invisible skyscraper” IN SOUTH KOREA (under construction)

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CONCLUSIONIs invisibility possible? ----> Yes!Is invisibility simple to accomplish? ---> No! However, we have already realised the 2D invisibility, we created the special materialmetamaterial which has a lot of applications.

Technology can change the world We are on the way to the 3D invisibility...

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THANK YOU FOR YOUR ATTENTION!ANY QUESTIONS?