Patent ID: 8102593

Claim:
A quasi non-critically phase matched optical assembly capable of correcting walk-off of an impinging radiation beam, comprising: at least one pair of nonlinear optical crystals, each individual crystal being critically phase matched and having a pair of opposing end faces, wherein the pair of crystals are cut from the same single crystal and have the same length between end faces, and wherein the crystals each have an identical cut of an end face relative to an optical axis of the single crystal, wherein the pair of crystals are bonded together to form a bonded pair that behaves as a quasi non-critically phase-matched optical assembly, and arranged with the same polarity of effective nonlinear coefficient in each crystal even though the crystal alignment may be different for different crystal symmetric groups and phase matching types, wherein the bonded pair corrects for walk-off of an impinging radiation beam that traverses the pair and provides increased angular acceptance of the impinging radiation beam relative to a single crystal.