The morphology of craters on the YAG crystal surface caused by broadband (≈500 Å) nanosecond laser pulses with intensities 10 9 -10 10 W cm −2 was studied. A mechanism of structural changes and the appearance of craters due to plastic deformations in the crystal are discussed.

Nanosecond pulses of broadband collimated generation in the wavelength region of 1.0–1.06 μm were observed at focusing the pump radiation from LiF:F2+ color center laser onto the plates from YAG:Yb crystal or Yb-doped phosphate glass. Spectra of the widths up to 200 Å for YAG:Yb and up to 500Å for glass were registered. The angular divergence (10-3–10-4 rad) of broadband radiation from the emitting area of 100–200 μm in diameter was by 1–2 orders of magnitude smaller than the diffraction limit corresponding to this area. Physical mechanism responsible for the occurrence of highly collimated broadband lasing under stimulated Brillouin scattering (SBS) of the pump radiation in the active medium is discussed.

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