Crystal high-power laser

Three basic questions must be answered to ensure success in the search for an optimized nonlinear crystal for a particular application What are the most important optical properties which determine the crystal s figure of merit for the intended application What is the best methodology for characterizing those optical properties so that materials of interest can be identified efficiently Where in "materials space" can crystals with such properties be found with the highest probability Answers to these questions will be discussed in the context of a program to find improved frequency conversion crystals for high power lasers. 

The lower the threshold power, the easier it is to achieve high conversion efficiency of the noisy pulses and abberated beams which are typical of high-power lasers. Materials with threshold powers an order of magnitude lower than KDP could achieve conversion efficiencies closer to 90% for beam of similar quality to Nova. This has motivated us to undertake a broad and systematic search for such crystals. 

It is important to note that, with the exception of the extraordinarily large aperture size requirement, the criteria for a fusion laser frequency convertor are generally applicable to any high power laser. Moreover, many of the ideas presented here are applicable, mutatis mutandis, to the search for NLO crystals for any specific application, for example, diode laser doubling. 

Taniguchi, et al. [99] have tested the one- and two-photon excitation for [Cr(acac)3]3- for several irradiation wavelengths but found no indication of a superlinear dependence of photoracemization or photodecomposition. This seems to be in line with the experiments of Gunde and Richardson [6] on Na3[Gd(02C-CH2-0-CH2-C02)3] 2NaC104 6H20 crystals. The possibility discussed in several papers [4-6] that in high-intensity radiation fields a pure electric dipole 2-photon absorption may lead to CD effects adds a new possibility of rationalization of the high-power laser results. 

The high optical quality of fluoride crystals make them attractive for laser applications. Because of low nonlinear index, they can sustain high peak powers without causing beam distortion. LiYF4 Nd (A = 1.053 /xm) is used as amplifiers in high power lasers. It also has significant advantage over YAG Nd3+ for diode-pumped systems [14]. 

In crystal composites, there is no chemical bond between the two crystals at the interface, which leads to low mechanical strength, low thermal conductivity, and poor thermal diffusivity. Therefore, such crystal composites cannot be used for high-power lasers, because the defects at the interface will absorb thermal energy, thus leading to decrease in beam quality and lasing efficiency. Due to potential... 

The flame-fusion process allows the dopant concentration of the growing crystals to be changed during growth by means of a double-feeder system shown in Fig. 16.13. This allows growth of, for example, ruby laser crystals with sapphire ends for high-power laser crystals with reduced surface damage. 

Fig. 17.7 The principle of laser-fusion energy is shown where the laser crystal is pumped by laser-diode arrays and where the frequency of the infrared radiation from the high-power laser crystal is multiplied by...

Novel high-power laser crystals and radiation-resistant nonlinear-optic crystals for laser-fusion energy (and for future ultraintegrated microelectronic/UV-lithography). 

Although most optical elements involve low level light, liquid crystals are actually excellent laser-hardened materials capable of handling very intense pulsed lasers or high power continuous wave cw lasers. These studies have shown that common liquid crystals such as 5CB and E7 can withstand a nanosecond laser pulse of 10 J/cm (corresponding to an intensity 10 W/cm ), thus making them particularly useful to construct high power laser optics such as polarization rotators, wave plates, optical... 

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