Dependence of far-field characteristics on the number of lasing modes in   stadium-shaped InGaAsP microlasers
  We study spectral and far-field characteristics of lasing emission from stadium-shaped semiconductor (InGaAsP) microlasers. We demonstrate that the correspondence between a lasing far-field emission pattern and the result of a ray simulation becomes better as the number of lasing modes increases. This phenomenon is reproduced in the wave calculation of the cavity modes. 
Muhan Choi, Susumu Shinohara, Takahisa Harayama