[1] Hemmerich A. Compact source of coherent blue light. Appl. Opt., 1994, 33(6):988~991
[2] Mizell G J, Fay W K. Performance of KN in the generation of blue laser light using Ti:Al2O3. Proc. SPIE, 1989, 1104:61~63
[3] Kean P N. Generation of 20 mW of blue laser radiation from a diode-pumped sum-frequency laser. Appl. Phys. Lett., 1993, 63(3):302~304