We present a practical route to designing a portable femtosecond blue light source that is rugged, compact and battery-powered. An opticaloptical second-harmonic generation (SHG) efficiency of 30% is reported using a diode-pumped, femtosecond Cr:LiSAF laser requiring only ~1.2W of electrical drive. 12mW of blue average power is generated using a 3mm KNbO3 crystal in a simple, single-pass extracavity geometry. The corresponding electrical-blue efficiency of 1% is, to our knowledge, the highest reported efficiency of any femtosecond blue source. Despite conditions of large group velocity mismatch, we show that the temporally-broadened blue pulses remain well within the femtosecond regime, at ~540fs.
|Number of pages||7|
|Publication status||Published - 2002|
- laser optics
- nonlinear optics
- harmonic generation