Narrow-band green coherent radiation has been successfully generated by a low-cost, small-sized and robust frequency doubled diode laser instead of a conventional frequency-doubled YAG laser. The non-critical phase matching condition is exploited by combining a 50mW diode laser at 1080nm with an a-cut KTP crystal. Green coherent radiation at 540nm in an ideal Gaussian beam profile is obtained with a conversion efficiency of 51.6%. Resonant optical feedback guarantees intensity fluctuation less than 0.3% and a linewidth less than 82kHz. The green radiation was used to pump an optical parametric oscillator comprising of an a-cut KTP crystal to yield 5.1mW of quantum-correlated twin beams exhibiting intensity-difference squeezing of 63%. This is the first demonstration of generation of non-classical light by a frequency-doubled diode laser. Generation of non-classical light by diode laser is advantageous in versatile, efficient, compact and low-cost quantum communications.
Related new resources
News Breaks in "Laser Focus World", Sep. 1. 2004
Optics Express 12, 3567 (2004)
Optics Letters 29, 1665 (2004)