Sum frequency generation of high power blue laser light for cooling of neutral strontium atoms

Abstract

Summary form only given. The development of a neutral strontium optical frequency standard requires a high power source of blue laser radiation at 461 nm in order to laser cool the largest possible number of atoms. Unfortunately there are no readily available compact solid state laser systems that meets this requirement. To overcome these problems we propose a novel design using doubly resonant sum frequency generation of a high power Nd:YAG laser at 1064 nm and a medium power diode laser at 813 nm. Both lasers are readily available as standard commercial products, while KTP crystal is much less sensitive to thermal effects and still rather efficient as a nonlinear crystal. Blue light is generated by a 20 mm long antireflection coated KTP crystal that is placed inside a non-monolithic standing wave resonator.