Scientific Glossary
- Scanning laser microscopy: Tool for obtaining high-resolution images and three-dimensional reconstructions.
- Second harmonic generation: A nonlinear optical process typically used to combine photons interacting with a nonlinear material to form new photons with twice the energy.
- Self-referencing technique: The establishment of a link between optical and microwave frequencies that can be used to measure an optical frequency relative to a radio frequency source.
- Semiconductor: Material with electrical conductivity intermediate between that of an insulator and a conductor where the movement of current is facilitated by both electrons and holes. Doping, temperature increases, and light can all increase conductivity in semiconductors.
- Singularity: The point inside a black hole where both gravity and the curvature of space/time become infinite.
- Soliton: A solitary, traveling wave that does not disperse or interfere with other waves.
- Solute: The substance dissolved in a solution.
- Solvation: The process by which solvent molecules surround and interact with (dissolve) solute molecules.
- Solvent: A gas or liquid that dissolves or disperses something else.
- Special relativity: Theory proposed by Albert Einstein stating that both distance and time and the perception of time and space depend on the observer.
- Spectroscopy: The study of the interaction of light (or other electromagnetic radiation) and matter.
- Spin: Weak magnetic energy state of electrons, characterized as "spin up" and "spin down."
- Spin-orbit relaxation: Nonradiative molecular electronic state transition.
- Spintronic devices: Analogs to electronics devices that exploit the quantum propensity of electrons to spin and make use of their charge state.
- Stark deceleration: The use of time-varying electric fields to slow down polar molecules.
- Steric effect: Related to the spatial arrangement of atoms in a molecule.
- Stellar wind: Analog of the solar wind in other stars.
- Streptavidin: A protein that binds very tightly to the vitamin biotin. The combination is used in a variety of biochemical assays.
- Superconductivity: Pairs of electrons flow with no resistance.
- Superfluidity: No resistance to flow.
- Supersonic expansion: Spreading out of atoms or molecules at speeds faster than sound.
- Sympathetic cooling: A process in which atoms (or isotopes) of one type cool those of another type that are harder to cool by themselves.