Quasi non-critical phase matched and contra-phase matched structures

Abstract

Adhesive-free bond non-linear optical (NLO) components, devices and systems including one or more engineered quasi non-critical phase matched or contra-phase matched NLO crystal doublets. Such systems and devices advantageously increase the efficiency of NLO frequency conversion and improve beam quality. Devices are applicable to any uniaxial and biaxial NLO crystals in a wide range of wavelengths, e.g., from far ultraviolet to visible to far infrared. Devices employing engineered AFB NLO components according to certain embodiments include any conventional frequency converting architectures. Systems and methods are also provided to unambiguously determine and correct walk-off for any arbitrary uniaxial and biaxial crystal orientation.

1 - 8 . (canceled) 
     
     
         9 . A method of forming a contra-phase matched optical assembly capable of correcting walk-off of an impinging radiation beam, comprising:
 cutting a single crystal having an optical axis and a pair of end faces so as to produce at least one pair of nonlinear optical crystals, each crystal having a pair of opposing end faces and 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,   arranging the crystal pair so that opposite polarity of the effective nonlinear coefficient is formed in the crystal pair even though the crystal alignment may be different for different crystal symmetric groups and phase matching types.   
     
     
         10 . The method of  claim 9  wherein bonding the crystal pair includes bonding without inorganic or organic adhesive. 
     
     
         11 . The method of  claim 10  wherein bonding the crystal pair includes bonding using an adhesive-free bonding process. 
     
     
         12 . The method of  claim 9 , wherein the single crystal is a frequency-converting biaxial crystal. 
     
     
         13 . The method of  claim 12 , wherein the single crystal is a biaxial crystal selected from the group consisting of KTP (KTiPO 4 ), LiB 3 O 5 , KNbO 3 , CsB 3 O 5 , BiB 3 O 6 , CsTiOAsO 4 , and RbTiOAsO 4 . 
     
     
         14 . The method of  claim 9 , wherein the length of the at least one pair of crystals is optimized based on the specific walk-off angle, the input beam diameter, and conversion efficiency. 
     
     
         15 . The method of  claim 9 , wherein the single crystal is a frequency-converting uniaxial crystal. 
     
     
         16 . The method of  claim 15 , wherein the single crystal is a uniaxial crystal selected from the group consisting of ZGP (ZnGeP2), β-BaB 2 O 4 , CsLiB 6 O 10 , LiNbO 3 , MgO:LiNbO 3 , AgGaS 2 , and AgGaSe 2 .