A method of bonding an RE:XAB gain medium to a heat spreader includes using a bonding solution of sodium silicate with concentration of sodium silicate is Na2O at 21.2% and SiO2 at 53% with PH>=11 mixed with nano-pure water in a 1:1 ration. Applying the bonding solution onto either a surface of the RE:XAB or a surface of the heat spreader, aligning the RE:XAB and the heat spreader, applying pressure to draw the surfaces of the RE:XAB gain medium and the heat spreader together thereby uniformly spreading the bonding solution; and then curing the bonding solution.