Improving the bulk laser damage resistance of potassium dihydrogen phosphate crystals by pulsed laser irradiation

We have obtained an increase (factors of 1.5–3.0) in the threshold fluence for laser‐induced inclusion damage in crystals of potassium dihydrogen phosphate (KDP) by irradiating the crystals at a fluence below that necessary to cause damage with a single laser pulse (1064‐nm, 1‐ns). The threshold increase was greatest for less damage resistant samples.