A one-dimensional acoustical composite-resonator model is used to study the behavior of a quartz-crystal resonator with large mass load. On the basis of this model, it is found that the exact relationship between the frequency shift and the added mass depends on the acoustic impedance of the deposited material. The experimental data for three materials (silver, copper, and lead) with different acoustic impedances are shown to be in good agreement with the theoretical predictions. The validity and limitations of the presently used equations for thickness determination by quartz-crystal resonators are also discussed.

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Progress in the development of Nd:glass active mirror laser amplifiers is presented. Included is a detailed discussion of hardware design as well as gain and repetition rate performance. Finally, multiunit test results, in a higher power and high energy beam, are presented.

A one-beam prototype of a large twenty-four-beam phosphate-glass laser system has been built and tested. Basic design characteristics include Nd-doped phosphate glass, rod amplifiers up to 90-mm diam, the propagation of a circularly polarized beam, extensive spatial filtering and imaging, and the use of large-aperture Pockels cells. The prototype system has demonstrated focusable power in excess of 750 GW/beam at 50-psec full width at half-maximum (FWHM) pulse duration and has delivered 165 J of focusable energy in a 500-psec (FWHM) pulse. Maximum beam brightness has been measured to be 4 x 10(19) W/cm(2) .sr at a firing rate of 2 shots/hr. Peak-to-background energy contrast of 10(8) has been achieved with this system. A detailed description of the system design and performance is presented.