Sci-Fi of Today: Invisibility Cloak Part 5
Last time we talked about active camouflage, the art of hiding one self from view by mimicking the background, but more specifically, we explored active camouflage using reflection and projection. This week we won’t let go of active camouflage just yet, but instead we will be exploring a different approach to active camouflage, pigmentation. In the third week of this invisibility cloak series we touched upon the animal kingdom and we saw that the kings of invisibility by mean of active camouflage were the cephalopod, which, if you are confused, are squids. Now while some people loves to work with artificial technologies, other would rather stay with the biological, and this week we will look at this more biological approach to achieve invisibility through active camouflage.
Now the essential for active camouflage stays the same, we are trying to achieve invisibility by blending with our background. we want to stay invisible even if the background or the thing to be invisible is moving, since immobility is quite impractical. Yet now we won’t use any fancy camera computer and projector, we will go a more natural route and instead try to imitate what nature already does so well. We will try to find a way to obtain pigmentation technology similar to those squids which would allow us to change each individual pore of an object to different color to adapt to the environment around it. Now if you try to look up more information about this kind of invisibility online you might come across quite the challenge. The information is sparse and difficult to find, this is because as previously said, this method would require us to mimic the cephalopod and it happens that…we know nearly nothing about them. In 2011 a science project of 5 million of dollar, funded by the U.S Navy, was started at Duke University and along with it came a report that explains what little we know about cephalopod and how their invisibility mechanism works.
So here is what we know, those animals are able to change their skin pigmentation depending on the intensity of blue-light that they receive, from there they can vary that pigmentation from very dark colors to complete invisibility. It is said that they could probably play a television show on their back, if their brain was powerful enough. Now doesn’t that sound interesting? If you can play a television show on your back, then surely you can reproduce your background too. Previously with the reflector and projector approach to invisibility we were quite limited since the invisibility only worked on one side and with a very fixed point of view. Now, with this change of pigmentation we don’t need anything to be projected onto the object to be invisible, the pigmentation that makes the so-called invisibility cloak will be the one making all the work and therefore the technology suddenly become much more portable.
So what exactly would we be trying to achieve here? Well there is different people looking to obtain different level of invisibility. If we can synthetically reproduce a product that could change pigmentation automatically depending on the intensity of the light around it, we could easily improve on the camouflage of many military vehicles and maybe even military uniforms. This would allow for partial invisibility where those cloaked objects would become either darker or more transparent depending on how much light there is outside. Now, while this sounds an interesting implementation and quite practical, it is obviously nowhere near the perfect invisibility we are trying to reach here, but considering our current mastery of this method, it is as far as we can steer this technology for now.
That said, it is now because we are nowhere near able to master this technology that we can’t already know how we could use this technology to greater effect. If our understanding of those pigment improves, we could be able to modify their color by electrical stimulation, it would be possible to have a computer that decides the color of each pigment. This computer could take information from a camera to know what color is the background and how to replicate it. Now this is starting to sound familiar isn’t it? Well it is mostly because since we are still talking about Active Camouflage, the final implementation remains pretty much the same. What do we gain then, some people may ask. Well we now have the same technology for perfect invisibility, but instead of needing an holographic projection to cover an object covered in reflective material, we simply use pigmented material which change color just like if you were wearing a portable television on yourself. This make it both more convenient and achievable, since good looking holographic projection is not something we are close to achieve in the next decade, and it is also a lot more convincing of an invisibility cloak if the very “cloak” you are wearing is “invisible”, and doesn’t simply project invisibility. Now we still have some of the same problems we previously had with active camouflage, we still need cameras to observe everything around the cloak to create a good replica and we need a small enough and powerful enough computer and electric circuit to stimulate correctly every single pixel of our cloak. While those are problem we are unable to address as of now, it would be reasonable to think that they could be solved in a 5 to 10 years time period if some investment was made on the technology, contrary to holographic display.
There is still 3 years to go before the Duke University research finishes and brings in conclusion. Depending on their finding and how likely they evaluate the possibility of using those pigmentation method for active camouflage, we could see a boom in our knowledge on that type of technology and it is possible that different application for adapting pigmentation come to our world soon enough. You know how some technologies are said to be in their infancies? Well this one isn’t even born yet. The only thing certain about it is that if it does happen, you can expect that invisibility will be an outcome very soon after.
This was the pigmentation method of active camouflage and it will be the final chapter on active camouflage. From next week onward we will look at other method of invisibility that does not involves camouflage, but usually instead try to avoid light. Next week we will look into the metamaterial that avoids light to make you invisible, stay tuned !
ZeroGhj signing off