I became fascinated with spintronics for about a year. Somewhat unrelated, but perhaps interesting to some readers, is that you can create spin-LEDs. If you use a material to permit only electrons of a certain spin (spin-up or spin-down) to transport to the excitation layer of the LED, the resultant emitted photons will be helically polarized. Fascinating stuff.
Good question, but I'm 99.9999% sure no. They may us Circularly Polarized light (I actually don't know), but if they do it's made by filtration of unpolarized light rather than polarized electroluminescence. When I was researching the topic (~2008-ish), Spin-LEDs were largely still in the lab - a lot of work at Stanford spintronics lab as I recall. At that time, they were able to achieve a strong bias of circularly polarized light. I just googled it and apparently there's beed good progress in 'purifying' the polarization handedness [1]. If you can harness CP emission, it opens the door for many very interesting applications. CP light is fascinating.
