Efficient direct amplification of powerful picosecond pulses in Nd-glass laser

The possibility of the efficient direct amplification of powerful picosecond pulses when the active element is pumped selectively by the second harmonic of a long pulse auxiliary laser. An important factor limiting the output energy of the high brightness neodymium laser is laser induced surface damage of optical elements. The experimental measurements of optical glass surface damage have been carried out with phosphate glass laser ‘‘PICO’’ facility. Measured damage thresholds are in the range 1–2.5 J/cm2 (or 200–500 GW/cm2) for thin samples of laser and optical glasses. The analysis of self‐focusing for thin Nd‐glass amplifiers with high amplification gain has been resulted in that the output energy more than 100 GW/cm2 can be utilized in this case.