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This sounds pretty neat. It sounds like it uses transormation optics, which I’ve just been reading about.

You know how a lens bends light, i.e. a light ray enters the lens and travels at a different angle that depends on the lens’s index of refraction? Now suppose the index of refraction changes continuously, like air’s index of refraction changes with temperature. So if you have warm air near the ground that gets cooler with height, light can actually travel through it by a curved path. That’s how mirages happen.

Now suppose you can somehow control the index of refraction in a volume of material. So you can imagine an “invisibility cloak” where light coming in from behind you gets steered around you and comes out in front of you. People looking straight at you see the light from in back of you so it’s like you’re invisible. This doesn’t seem technologically doable with visible light (at least for now) but it’s been demonstrated in the lab at microwave frequencies, with small objects like a few centimeters. It’s really cool how the math works.

This sounds like they’ve done something similar with heat. They use a 3D printed heat sink with a special shape to make the temperature in front of something look like the temperature behind the thing, masking the heat source in the middle.

If you look up “transformation optics” there’s a lot of stuff about invisibility cloaks, maybe because there’s military funding in the field and the army wants to make stuff invisible, lol. But the math and physics are interesting even if the applications are overstated. It turns out that the math used in studying how the materials curve light is similar to the math of general relativity, which is about how gravity bends light near stars and black holes. So that also leads to a bunch of breathless headlines about making black holes in the laboratory. It’s not 100% bogus (they do get some cool effects) but yeah, of course it’s an analogy, not an actual black hole.

Here’s a TED talk by one of the guys involved with this. I haven’t watched it yet but maybe I will. I saw another youtube lecture by him and it was interesting. www.youtube.com/watch?v=v9d-EBgro50

This sounds pretty neat. It sounds like it uses transormation optics, which I’ve just been reading about.

You know how a lens bends light, i.e. a light ray enters the lens and travels at a different angle that depends on the lens’s index of refraction? Now suppose the index of refraction changes continuously, like air’s index of refraction changes with temperature. So if you have warm air near the ground that gets cooler with height, light can actually travel through it by a curved path. That’s how mirages happen.

Now suppose you can somehow control the index of refraction in a volume of material. So you can imagine an “invisibility cloak” where light coming in from behind you gets steered around you and comes out in front of you. People looking straight at you see the light from in back of you so it’s like you’re invisible. This doesn’t seem technologically doable with visible light (at least for now) but it’s been demonstrated in the lab at microwave frequencies, with small objects like a few centimeters. It’s really cool how the math works.

This sounds like they’ve done something similar with heat. They use a 3D printed structure to make the temperature in front of something look like the temperature behind the thing, masking the heat source in the middle.

If you look up “transformation optics” there’s a lot of stuff about invisibility cloaks, maybe because there’s military funding in the field and the army wants to make stuff invisible, lol. But the math and physics are interesting even if the applications are overstated. It turns out that the math used in studying how the materials curve light is similar to the math of general relativity, which is about how gravity bends light near stars and black holes. So that also leads to a bunch of breathless headlines about making black holes in the laboratory. It’s not 100% bogus (they do get some cool effects) but yeah, of course it’s an analogy, not an actual black hole.

Here’s a TED talk by one of the guys involved with this. I haven’t watched it yet but maybe I will. I saw another youtube lecture by him and it was interesting. www.youtube.com/watch?v=v9d-EBgro50

This sounds pretty neat. It sounds like it uses transormation optics, which I’ve just been reading about.

You know how a lens bends light, i.e. a light ray enters the lens and travels at a different angle that depends on the lens’s index of refraction? Now suppose the index of refraction changes continuously, like air’s index of refraction changes with temperature. So if you have warm air near the ground that gets cooler with height, light can actually travel through it by a curved path. That’s how mirages happen.

Now suppose you can somehow control the index of refraction in a volume of material. So you can imagine an “invisibility cloak” where light coming in from behind you gets steered around you and comes out in front of you. People looking straight at you see the light from in back of you so it’s like you’re invisible. This doesn’t seem technologically doable with visible light (at least for now) but it’s been demonstrated in the lab at microwave frequencies, with small objects like a few centimeters. It’s really cool how the math works.

This sounds like they’ve done something similar with heat. They use a 3D printed structure to make the temperature in front of something look like the temperature behind the thing, masking the heat source in the middle.

If you look up “transformation optics” there’s a lot of stuff about invisibility cloaks, maybe because there’s military funding in the field and the army wants to make stuff invisible, lol. But the math and physics are interesting even if the applications are overstated. It turns out that the math used in studying how the materials curve light is similar to the math of general relativity, which is about how gravity bends light near stars and black holes. So that also leads to a bunch of breathless headlines about making black holes in the laboratory. It’s not 100% bogus (they do get some cool effects) but yeah, of course it’s an analogy, not an actual black hole.