Characterization of off-axis superposition of partially coherent beams

The Gaussian Schell model (GSM) is used to describe partially coherent beams. The characteristics of the off-axis superposition of partially coherent beams, such as the beam quality in terms of the M 2 factor and power in the bucket (PIB), kurtosis parameter K and irradiance distribution are studied theoretically and numerically by using the Wigner distribution function. It is shown that the M 2 factor, PIB and K parameter of the resulting beam are dependent on the global degree of the spatial correlation α, separation x d , waist width w 0 and number N of GSM beamlets. Better beam quality of the resulting beam measured by the M 2 factor and/or PIB can be achieved for beamlets with larger α.