Laser crystallization

Figure 5.5. Raman spectroscopy of laser crystallized solution-processed silicon films. The plot shows laser intensity versus Raman shift of the film. The crystallinity is estimated from the intensity and width of the crystalline peak at 520 cm-1. [Reproduced with permission from Ref. 11. Copyright 2006 The Japan Society of Applied Physics.]...

Kitahara, K. Yamazaki, R. Kurosawa, T. Nakajima, K. Moritani, A. 2002. Analysis of stress in laser-crystallized polysilicon thin films by Raman scattering spectroscopy. Jpn. J. Appl. Phys. 41 5055-5059. 

Gosain, D. P. 2002. Excimer laser crystallized poly-Si TFT s on plastic substrates. Proc. SPIE 4426 394 00. 

EXAMPLE 1.7 The fluorescence lifetime measured from the metastable state Ej/2 ofNd + ions in the laser crystal yttrium aluminum borate (YAl3(B03)4) is 56 lus. If the quantum efficiency from this state is 0.26, determine the radiative lifetime and the radiative and nonradiative rates. 

EXAMPLE 2.3 Suppose that a 7.5 cm length rod ofaNd Y3AI5O12 (Nd YAG) laser crystal is located in a linear cavity with two mirrors of transmittances Ti =0 and T2 = 0.5 at the laser wavelength (1.06 /am). If the cross section is a = 8.8 X 10- crn, determine the population inversion density at threshold. Assume that losses are only due to the output mirror transmittance. 

EXAMPLE 2.5 For a Nd YAG laser crystal located in a cavity of length 0.1 m, determine (a) the frequency separation among the axial modes and (b) the number of axial modes. Assume that the laser is operating in a laser line at 1.06 fxm, whose full width, Sv, is 1.1 x 10 Hz. 

Kaminskii, A. A., in Laser Crystals, ed. D. L. MacAdam, Springer-Verlag, Berlin (1981). 

Certainly, this rongh calcnlation leads to a value that is very close to the real quantum efficiency for this famous laser crystal, which is close to 1. 

The Yb + ion is commonly used to make solid state laser crystals. In which spectral range do you expect these lasers to emit ... 

CnLiSAF laser crystal does not require any cooling. As a result, relatively inexpensive femtosecond CnLiSAF lasers with optical output powers up to 45 mW, robustly modelocked with a semiconductor saturable absorber mirror (SESAM), are achievable from entbely self-contained and portable units with dimensions of 22 cm x 28 cm. [A version of this laser design incorporating one pah of pump laser diodes is shown in figure 10] A second pah of pump laser diodes can easily be incorporated onto the baseplate to maximize operational performance (figure 12). 

Nassau 110) has published the concentration dependence of the fluorescent lifetime of neodymium in CaW04 Nd3+ Na+. All studies were made on very high-quality laser crystals. The neodymium concentration varied from 0.1 to 5.5 atomic per cent the charge compensating sodium was held fixed at 12 atomic per cent. All data were collected at 77°K. 

A redox titration is based on an oxidation-reduction reaction between analyte and titrant. In addition to the many common analytes in chemistry, biology, and environmental and materials science thai can be measured by redox titrations, exotic oxidation states of elements in uncommon materials such as superconductors and laser materials are measured by redox titrations. For example, chromium added to laser crystals to increase their efficiency is found in the common oxidation states +3 and +6, and the unusual +4 state. A redox titration is a good way to unravel the nature of this complex mixture of chromium ions. 

Calcium fluorapatite (Ca,0(PO4)6F2, FM 1 008.6) laser crystals were doped with chromium to improve their efficiency. It was suspected that the chromium could be in the +4 oxidation state. 

Strauss. S. "Impossible Matter, Technology Review [MlTi. 10 (January 1 191 ). Uhrin, K. Selected Papers on Laser Crystal Gnmrh, SPIE International Society lor Optical Engineering." Bellingham. W.A. 2000. 

Jahn-Teller Effect in Laser Crystal LiCaAlF6 Cr3+... 

Jahn—Teller Effect in Laser Crystal LiCaAIF6 Cr3... 

---