Search results
Results from the WOW.Com Content Network
The carbon-dioxide laser (CO2 laser) was one of the earliest gas lasers to be developed. It was invented by Kumar Patel of Bell Labs in 1964 [1] and is still one of the most useful types of laser. Carbon-dioxide lasers are the highest-power continuous-wave lasers that are currently available. They are also quite efficient: the ratio of output ...
Another very important mode is the G mode (G from graphite). This mode corresponds to planar vibrations of carbon atoms and is present in most graphite-like materials. [8] G band in SWNT is shifted to lower frequencies relative to graphite (1580 cm −1) and is split into several peaks. The splitting pattern and intensity depend on the tube ...
Scattering. In physics, Raman scattering or the Raman effect (/ ˈrɑːmən /) is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted ...
Raman spectroscopy. Energy-level diagram showing the states involved in Raman spectra. Raman spectroscopy (/ ˈrɑːmən /) (named after physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. [1]
A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.
Mode locking. Mode locking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10 −12 s) or femtoseconds (10 −15 s). A laser operated in this way is sometimes referred to as a femtosecond laser, for example, in modern refractive surgery.
A carbon-dioxide laser. Carbon dioxide is the lasing medium in a carbon-dioxide laser, which is one of the earliest type of lasers. Carbon dioxide can be used as a means of controlling the pH of swimming pools, [138] by continuously adding gas to the water, thus keeping the pH from rising. Among the advantages of this is the avoidance of ...
Gas dynamic laser. A gas dynamic laser (GDL) is a laser based on differences in relaxation velocities of molecular vibrational states. The lasing medium gas has such properties that an energetically lower vibrational state relaxes faster than a higher vibrational state, and so a population inversion is achieved in a particular time.