Investigation on Intracavity SHG With Controllable Coherence in a Degenerate Laser

We investigate intracavity second harmonic generation (SHG) in a degenerate laser for generating green laser with controllable degree of coherence. It is shown that spatial coherence of the SHG emission can be controlled by varying the diameter of the limiting aperture in the degenerate laser resonator. The pumping power also affects the number of the oscillating transverse modes, so that influences the spatial coherence of the output laser. The laser of low coherence for speckle reduction has been demonstrated. It is shown that the laser of low spatial coherence may find applications in imaging, and laser display etc.