(self)
return self.z*(1 + (self.z/self.z_r)**2)
The radius of curvature of the phase front.

        Examples
        ========

        >>> from sympy.physics.gaussopt import BeamParameter
        >>> p = BeamParameter(530e-9, 1, w=1e-3)
        >>> p.radius
        0.2809/pi**2 + 1
The radius of curvature of the phase front.
The radius of curvature of the phase front .
def radius(self):
        """
        The radius of curvature of the phase front.

        Examples
        ========

        >>> from sympy.physics.gaussopt import BeamParameter
        >>> p = BeamParameter(530e-9, 1, w=1e-3)
        >>> p.radius
        0.2809/pi**2 + 1
        """
        return self.z*(1 + (self.z/self.z_r)**2)
def radius ( self ) : return self . z * ( 1 + ( self . z / self . z_r ) ** 2 )