Reverseable Color Change of a Polymer with Laser

no, but interesting.

I found an expensive book too.

Photochromism is the reversible phototransformation of a chemical species between two forms having different absorption spectra. During the phototransformation not only the absorption spectra but also various physicochemical properties change, such as the refractive index, dielectric constant, oxidation/reduction potential, and geometrical structure. The property changes can be applied to photonic equipment such as erasable memory media, photo-optical switch components, and display devices. This book compiles the accomplishments of the research project titled “New Frontiers in Photochromism” supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The project focused not only on the above-mentioned classical subjects in photochromism, such as color changes, optical memory, and optical switches, but also on fundamental physicochemical studies and unprecedented application fields that have not yet been explored in photochromism. The latter topics include light-driven mechanical motion, photocontrol of surface wettability, metal deposition on solid materials, photocontrol of chiral properties, ultrafast decoloration dyes, and femtosecond laser experiments, among others.

Maybe this...

https://www.laserfocusworld.com/optics/article/16556390/gel-mimics-color-change-of-cephalopods

Thanks,Rixter.

What I have in mind is a memory device,either jell or solid that can change opacity or color with the application of a particular wavelength or intensity of laser light,then reversed by a different freq or intensity.

This would enable 3D memory storage and retrieval,using lasers on the X Y axis to write/read

How many sub-microscopic dots can be put into a 25X25MM cube?

I am thinking Yottabytes or even a Domegemegrottebyte?

It would depend on the size of the laser dot,which in incredibly small,and the thermal conductivity of the media.

The read/write ability would be incredibly fast if the media allowed.

Alternatively, could the magnetic polarity of a "dot" be flipped instead?

What you describe sounds a bit like rewritable CDs and DVDs. Writing ones, zeros, or reading is done by varying the laser power.

"For additional rewriteable capability (CD-RW), a thin layer of so-called phase-change metal replaces the dye layer. That material requires two extra "dielectric," or glassy, layers for protection. The drive employs a high-power laser to write amorphous marks in the metal layer, an intermediate-power level to write crystalline marks and a low-power level to read the recorded data. To the drive, the crystalline areas appear bright and the amorphous areas appear dark. As a result, the disc can be read in the same manner as a CD-ROM."

https://www.scientificamerican.com/article/how-do-rewriteable-cds-wo/

Yes,that's true,but this is still basically 2 dimensional,multi-layer on a flat plane.

Image the capability if it was 3 dimensional;A ball or cube with molecule or even atom-sized memory elements.

The problem with 3 dimensions, I think, is that you have to get the light beam in (and out) without something getting in the way...

https://en.wikipedia.org/wiki/Hybrid_Memory_Cube

https://www.sainsmart.com/products/3d-led-light-square-diy-kit

You could make something mechanical in nature that had different colored dyes that could pump the dye into a membrane that was squished between two plane surfaces so that when a signal was sent each of the dyes would pump in one direction or the other changing the color, sort of like pores in the skin, or you could just use light with fiber optics to turn on off or blend....

Possibly you mimic the response of cuttlefish by including patterns with the colors for even more effects...

..."Photographs fade, books rot, and even hard drives eventually fester. When you take the long view, preserving humanity's collective culture isn't a marathon, it's a relay — with successive generations passing on information from one slowly-failing storage medium to the next. However, this could change. Scientists from the University of Southampton in the UK have created a new data format that encodes information in tiny nanostructures in glass. A standard-sized disc can store around 360 terabytes of data, with an estimated lifespan of up to 13.8 billion years even at temperatures of 190°C. That's as old as the Universe, and more than three times the age of the Earth.

"WE CAN ENCODE ANYTHING. JUST GIVE US THE FILE."

The method is called five-dimensional data storage, and was first demonstrated in a paper in 2013. Since then, the scientists behind it say they've more or less perfected their technique, and are now looking to move the technology forward and perhaps even commercialize it. "We can encode anything," Aabid Patel, a postgraduate student involved in the research tells The Verge. "We’re not limited to anything — just give us the file and we can print it [onto a disc].""....

https://www.theverge.com/2016/2/16/11018018/5d-data-storage-glass

Maybe it's possible to build a cube that has entangled particles, that way you could control it from the sister particles in a separate device...

Plants and some cyanobacteria do what you are describing to respond to seasonal changes with 'phytochromes'.

Basically phytochromes in plants are great absorbers of mid red fequency of light (and so appear blueish-green to us). When hit with mid red light the phytochrome changes color in becoming a good absorber of far red frequency (appearing more greenish to our eyes). When hit with far red frequency it converts back to the original mid red sensitive form. The amounts of far red to mid red phytophores correspond to the variation in light with the season....a lot more far red to mid red in the fall than in the summer

<...anyone...>

This little grobbly might:

I realize that what I seek is probably not presently available or possible to construct,but this is a mental exercise on how the technology might be constructed.

The ideal media would be transparent to certain frequencies,say for instance 3 frequencies, like RGB.

When combined on a focal point,they would add to become white light which would have enough combined energy from the three beams to create a change.

They would remain transparent to individual wavelengths even after the "color" change.

That change does not have to be "color", simply a change in characteristics of that particular point.ie; polarization,magnetic polarity or orientation,shape,density,phosphorescence or fluorescence,etc.

The aim is a very high density storage/retrieval media that would surpass all present methods.

Pass the pie-in-the sky please!

You picked a fine time to elaborate Lucille.

Still interesting, but we can't even decode our own megalithic past?!

I doubt the next inhabitants will be able to decode the ultimate repository of the human suppository better known as the drivel of the twiiterverse and cat videos etc.

I can hardly fathom the sea.

Feedback from this forum required me to refocus on a different goal,hence the change in details.

As far as future inhabitants,they will probably try to construct our civilization by the land fills and automobile recycle yards.

They will think we mainly ate hot dogs,which will still of course be edible even after millions of years.The trains and tractor trailers will be the T Rex and brontosaurs of our time,with large capacity stomachs and powerful muscles to propel all of that mass.

The smaller vehicles found in parking lots will be the mice and rats that are everywhere.

The cars in car carriers will be considered to be parasites,riding on the backs of the larger animals.

Motorcycles will have evolved into trikes,and then into cars.

The may even find a few tractors copulating.

I have seen them on the interstate with one tractor riding with it's front wheels on the fifth wheel of the one in front,looking like farm animals.

Crazy?Sure! But I have a lot of fun,and I don't have to explain a lot.

I guess we will be the owl pellets consumed by the beasts!

good thoughts