Hobbies And Interests
Optical Filters
The glare of reflected sunlight aligns in a horizontal direction. This is the effect of reflections from a highway or sea surface. Polarizing sunglasses use a surface coating to protect the eyes from this glare. The molecules of the coating align in a vertical direction and permit only vertical light to pass. Magnesium fluoride is the most common material used for anti-reflective coatings. Occasionally, thin films of tungsten, molybdenum or silicon are used.
Nuclear Spin Polarization
Nuclear spin polarization is the alignment of subatomic particles such as protons in a specific direction. A magnetic field can align moving, electrically-charged particles. This is achieved by passing the particle beam through a surface coating of ferromagnetic material such as chromium oxide. Polarized particles improve the techniques of nuclear magnetic resonance spectroscopy. This uses a beam of magnetized atomic nuclei to investigate materials ranging from atoms and crystals to machine parts and human organs.
Electron Spin Polarization
The principles of electron spin polarization are the same as that for atomic nuclei. This has applications in the production of high technology electronic goods. In this case, the polarizing material can be a coating of europium sulfide on tungsten. Europium is the scarcest and most expensive of the rare earth metals. It is used commonly in LED displays, computer monitors and televisions.
Beam Splitter
Beam splitters are optical surfaces that can split a beam of light into a transmitted beam and a reflected beam. At its simplest, this can be a two-way, or partially-reflective, mirror. A surface coating can ensure both of the split beams are polarized. Such coatings may be thin layers of tantalum oxide or aluminum oxide. These light-splitting devices are used to build interferometers, instruments used in astronomy for calculating distances between stars.