Optically pumped

A. Since tire applied field is red detuned, all A have negative values. Now in order for tire cooling mechanism to be effective tire optical pumping time tp should be comparable to tire time required for tire atom with velocity v to travel from tire bottom to tire top of a potential hill,... 

A wide variety of metliods has been used to pump laser systems. Altliough optical pumping has been implied, tliere is an array of collisionally or electron impact pumped systems, as well as electrically pumped metliods. The efficiency of tire pumping cycle in many ways defines tire utility and applications of each scheme. The first... 

Fig. 1. Pumping methods for lasers where is the pump light frequency and is the laser frequency, wavy lines represent radiationless transitions, and the dashed line collisions (a) optical pumping in three-level systems (b) optical pumping in four-level systems (c) pumping by electron impact and...

Figure lb shows a four-level system. The terminal level, level 2, is ordinarily empty. Atoms are optically pumped to level 4. From level 4, the atoms make a rapid radiationless transition to level 3. The first few atoms to arrive begin to contribute to the population inversion. Therefore, laser operation can begin with much less intense pumping light. After the laser transition, the atoms return to the ground state (level 1) by a radiationless transition. 

V.G. Kozlov, V. Bulovic, P.E. Burrows, M. Baldo, V.B. Khalfin, G. Pailhasarathy, S.R. Forrest, Y. You, M. E. Thompson, Study of lasing action based on Forster energy transfer in optically pumped otganic semiconductor thin films, J. Appl. Phys. 1998, 4, 4096. 

G.J. Denton, N. Tessler, M.A. Slevens, R. H. Friend, Spectral narrowing in optically pumped polyO -phenylencvinylene) films, Adv. Mater. 1997, 9, 547. 

Fig. 5.3.8 Photograph of the detection region of the NMR probe with radiofrequency coil. A methane—air mixture was ignited above the zeolite pellets. The mixture also contained xenon for NMR detection. Hp-129Xe NMR spectra with 30% xenon (from high-density xenon optical pumping) in 70% methane is depicted. (1) The spectrum in the absence of combustion and (2) the spectrum during combustion. Adapted from Ref. [2],...

---