Q-switched ruby laser

A series of papers by. Menichelli Yang (Refs 82, 84 86) showed that Q-switched ruby lasers could initiate steady detonation in PETN (and RDX or Tetryl) in <0.5 psec when a lOOOA-thick Al layer was deposited on the face of the sample, and subsequently exposed to laser radiation of 0.5 to 4.2 J with a pulse width of 25nanosec... 

A quantitative determination of two-photon absorption cross-sections from direct measurements of chemical yield was performed by Speiser and Kimel i ) who studied the two-photon-induced photolysis of iodoform with a Q-switched ruby laser. 

Fig. 8. Laser intensity S and dye population density difference between ground state and excited state, mo—mi, versus time for a typical example of a Q-switched ruby laser. (From Ref. D)...

Figure 28.11 Apparatus for photoemission measurements. L, Q-switched ruby laser d, frequency doubler F, CuS04 solution filter SR, screened room D, diaphragm PD, photodiode SO, storage oscilloscope C, cell P, polarizing circuit A, wideband amplifier O, oscilloscope. The mercury pool working electrode is renewed continuously from the reservoir at the upper right. [From Ref. 61.]...

Expts were also conducted using a ruby laser of 50 MW emitting 25 nanosecond flashes at 6943A Vollrath reported that Pb. and Cd azides are less sensitive at 6943A than at 10600A, while Pb styphnate is more sensitive At PicArsn Kessler (Ref 170) conducted expts with Q-switched and non-Q-switched ruby lasers... 

V.J. Menichelli, Detonation of High Explosives by a Q-Switch Ruby Laser , ApplPhys-Ltrs 19 (11), 473-75 (1971) 208) P.W. 

Kurtz and Giordmaine 79> were the first to observe stimulated Raman scattering at the polariton associated with the TO phonon at 630 cm-1 which was shifted to 497 cm-1 for 0° scattering excited with a Q-switched ruby laser. The corresponding phonon was also observed in this experiment. This can be explained by backward (180°) stimulated Raman scattering reflected from the laser resonator mirrors as confirmed by measurements of relative time of arrival at the spectrometer. 

Short energetic laser pulses, low rep rate (ex. dye, Nd YAG, Q-switched ruby lasers) Yes No Yes... 

While Brish et al. directly irradiated the explosive sample with the laser beam, Menichelli and Yang coated a glass window with a 1000 A thick aluminum film. Irradiation of this film generated shockwaves by vaporization of the metal, similar to the functionality of EBWs. [15c, 15d], The generated shockwave is able to directly initiate secondary explosives. In the work of Menichelli and Yang, a Q-switched ruby laser was successfully used (E = 0.8 to 4.0 J r = 25 ns) to initiate PETN, RDX and tetryl. 

Q-switched Ruby Laser 694.3 nm Pulse energy 2-8 Pulse duration 20-30... 

A 55-year-old woman who had taken amiodarone 250 mg/day for about 10 years developed bluish-gray discoloration of the face (195). The pigmentation responded to treatment with a Q-switched ruby laser at an energy of 8 J/cm and a wave length of 694 mm. 

Karrer S, Hohenleutner U, Szeimies RM, Landthaler M, Hruza GJ. Amiodarone-induced pigmentation resolves after treatment with the Q-switched ruby laser. Arch Dermatol 1999 135(3) 251-3. 

An ideal monochromatic source is the laser or uvaser. There is little or no published work on continuous photolysis using these sources although we must be on the threshold of this happening. Porter and Steinfeld have flash-photolysed phthalocyanine in the vapour phase using a Q-switched ruby laser. This emits at 6943A, and 2-3 J are dissipated in 20 psec. Photolysis occurs because of a two-photon process. 

Fig. 10.13. Random and channeling backscattering spectra of as-implanted Si (100) showing the annealing results from pulsed laser irradiation (Q-switched ruby laser 1.6 J cnT2, 75As 100 keV, 1.4 x 10ls in (100) Si, [110] aligned spectrum) (after White et al. 1979)...

At PicArsn Kessler (Ref 170) conducted expts with Q-switched and non-Q-switched ruby lasers... 

Taylor CR, Anderson RR (1994) Ineffective treatment of refractory melasma and post-infleunmatory hyperpigmentation by Q-switched ruby laser. J Dermatol Suig Oncol 20 592-597... 

H. Mocker, R.J. Cohins Mode competition and self-locking effects in a Q-switched ruby laser. Appl. Phys. Lett. 7, 270 (1965)... 

A number of the well-known radiation-induced centers in silicon, which are known to involve broken bonds, are also neutralized by atomic hydrogen. For exanple, the A-center (oxygen+vacancy coitplex, -0.18 eV), and divacancy level (E -0.23 eV) may be passivated [65]. Point defects produced by the Q-switched ruby-laser-annealing of both n-type [66] and p-type [67] Si surfaces are neutralized to the melt depth of - 1 /mi by plasma exposures of just 10 minutes at 100°C. And there has been a lot of work on the passivation of the electrical activity associated with dislocations (and their attendant point defects) and grain boundaries [66-76], which is so helpful in making photovoltaic solar cells from polycrystalline materials. While these defects may involve broken bonds, it should be remembered that these... 

The passivation of two deep-level electron traps induced in n-type Ge by a Q-switched ruby laser anneal was found [141]. As with the corresponding case in Si, plasma exposures of 10 minutes at 100 C were sufficient to neutralize the electrical activity of such centers. In Ge most radiation damage or quenched-in centers that have been found are vacancy-related, and again the propensity of hydrogen to neutralize this type of defect is seen by the effectiveness of hydrogen plasma exposures in passivating Co-60 Y-induced hole traps [142], quenched-in acceptors [143], and ion-implanted oxygen-related deep levels [144]. 

In the collinear arrangement the anti-Stokes wave at = 2o)i-(<)2 (w > Wj ) is detected through filters which reject both incident laser beams and also the fluorescence which may be generated in the sample. Figure 8.12 illustrates a typical experimental setup used for rotational-vibrational spectroscopy of gases by CARS [8.50]. The two incident laser beams are provided by a Q-switched ruby laser and a tunable dye laser, pumped by this ruby laser. Because the gain of the anti-Stokes wave depends quadratically on the molecular density N, see (8.33), high power levels of the incident... 

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