Recent content by theDoc

I don't see how Feynman's argument about the ratchet works in this case. This is a very simple experiment: at room temperature, place a 1 sq. meter sheet of black material (for e.g. http://www.pnas.org/content/106/15/6044.full) on top of a 1 sq. meter sheet of THz rectennas (like in...

Rectennas are diodes attached to antennas. With current technology they can convert EM waves with frequency up to \approx 1 THz to electricity. Imagine an isolated room at 300^{o} K containing a black object and a rectenna. By Planck law, the black object radiates about 450W/m^{2}, of which...

you guys are right, my mistake: the transmission is symmetric. It's not so simple to build something with asymmetric transmission, but maybe possible: http://arxiv.org/abs/1005.1970

Andy: It's been calculated by Lord Rayleigh in 1880 http://www.nature.com/nphoton/journal/v1/n3/full/nphoton.2007.26.html and the calculation is really straightforward. The formulas are in http://en.wikipedia.org/wiki/Fresnel_equations It is well known that a gradient of increasing refractive...

Imagine a closed isolated system consisting of 2 rooms separated by a window. The window is built with one layer of material that has refractive index 1.5 and one layer of material that has refractive index 2, for a wide range of wavelenghts (say 1 \mu m - 50 \mu m), and low absorption. The side...