Ali Khademian

Blue laser via IR resonant doubling with 71% fiber to fiber efficiency

We report on high efficiency resonant doubling to 486 nm using periodically poled KTP. The IR laser source is an FBG stabilized semiconductor laser with a maximum polarization maintaining (PM) fiber coupled output of 840 mW. An output power of 680 mW at 486 nm was obtained from our optimized cavity, giving net efficiency of 81%. Also, we report an 87.5% net efficiency in coupling of this blue light from the servo locked cavity into a single-mode PM fiber. This gives a total of 71% fiber to fiber efficiency. Furthermore, a wall plug efficiency of 21.4% was obtained.

Evaluation of a 486 nm single frequency source using an MgO:PPLN waveguide doubled semiconductor laser

A 972 nm semiconductor butterfly laser is stabilized with a fiber grating to single frequency (600 mW) and doubled in a MgO:PPLN waveguide (90 mW) for evaluation as a simple laser source for precision spectroscopy.

0.5W CW single frequency blue at 486 nm via SHG with net conversion of 81.5% from the NIR using a 30mm PPMgO:SLT crystal in a resonant cavity

A single frequency fiber Bragg grating (FBG) stabilized laser at 972 nm is coupled into a doubling ring cavity with an optical length of 138 mm, a 91% input coupler, a 30 mm long Brewster cut magnesium doped periodically poled lithium tantalate (PPMgO:SLT) crystal and a high reflector. The cavity buildup is 37 and loss is 0.63%. The cavity is monitored, controlled and locked with a single chip processor. With IR power of 572 mW in the input fiber, 466 mW blue output is obtained, giving 81.5% net efficiency. The blue and IR beams are separated by refraction at the crystal’s Brewster surface with negligible loss and without the need for dichroic optics.