3 ms·

I have known for a while (since I read Quicksilver) that gold becomes visibly transparent if you hammer it thin enough, and transmits greenish light, but I have

I have known for a while (since I read Quicksilver) that gold becomes visibly transparent if you hammer it thin enough, and transmits greenish light, but I have never been able to find a picture of this or a video of someone demonstrating it. How is this possible?

fnordfnordfnord 13y ago
You can buy a gold coated filter plate from a welder's supply for less than ten bucks.
sp332 13y ago
Gold reflects reddish light. That means only greenish light gets through. You don't need a solid piece of gold to see this; anything tinted with gold dust will work as well.
mercuryrising 13y ago
You've seen it before... Stained glass. Stained glass was one of the first use of nanoparticles and plasmonics to become commonplace. The wide range of colors that you can get in stained glass is due to the nano properties of the materials you add to the glass. The effect is due to surface plasmons - electric field waves that travel on the surface of conductors. Much like ocean waves, plasmons are created from light's electric field. They bounce back and forth, and since they are only permitted on the surface of a material, there are limits on what waves can exist. This is what gives them the weird properties - the size and shape determine the optical properties. On another tangent (this one's pretty cool) - since you can tune the properties of these nanoparticles, you can make them respond in a specific way. Let's say we have a cancer cell that we want to kill, and only that cancer cell should die. We can create nanoparticles that bond with that cancer cell, and only that cancer cell. But how do we kill it? We can tune the absorption spectrum of the nanoparticle to absorb infrared light - light that is transparent to the human body. We create a small heater that absorbs tons of the input energy, while keeping the rest of the area cool. Localized heating destroys the nearby cancer cell. Plasmonics are really cool - http://en.wikipedia.org/wiki/Plasmon http://en.wikipedia.org/wiki/Plasmon http://en.wikipedia.org/wiki/Plasmonic_Nanoparticles http://en.wikipedia.org/wiki/Plasmonic_Nanoparticles

fnordfnordfnord 13y ago

You can buy a gold coated filter plate from a welder's supply for less than ten bucks.

sp332 13y ago

Gold reflects reddish light. That means only greenish light gets through. You don't need a solid piece of gold to see this; anything tinted with gold dust will work as well.

mercuryrising 13y ago

You've seen it before... Stained glass. Stained glass was one of the first use of nanoparticles and plasmonics to become commonplace. The wide range of colors that you can get in stained glass is due to the nano properties of the materials you add to the glass. The effect is due to surface plasmons - electric field waves that travel on the surface of conductors. Much like ocean waves, plasmons are created from light's electric field. They bounce back and forth, and since they are only permitted on the surface of a material, there are limits on what waves can exist. This is what gives them the weird properties - the size and shape determine the optical properties. On another tangent (this one's pretty cool) - since you can tune the properties of these nanoparticles, you can make them respond in a specific way. Let's say we have a cancer cell that we want to kill, and only that cancer cell should die. We can create nanoparticles that bond with that cancer cell, and only that cancer cell. But how do we kill it? We can tune the absorption spectrum of the nanoparticle to absorb infrared light - light that is transparent to the human body. We create a small heater that absorbs tons of the input energy, while keeping the rest of the area cool. Localized heating destroys the nearby cancer cell. Plasmonics are really cool - http://en.wikipedia.org/wiki/Plasmon http://en.wikipedia.org/wiki/Plasmon http://en.wikipedia.org/wiki/Plasmonic_Nanoparticles http://en.wikipedia.org/wiki/Plasmonic_Nanoparticles