Study on the near field of semiconductor laser by using scanning near field optical microscope

The near field of a semiconductor laser was measured by using a Scanning Near Field Optical Microscope (SNOM). The near field emission was recorded during the scanning of the fiber tip above the facet of the semiconductor laser at a distance less than 20 nm. By controlling the shear force, the topography of the facet was recorded simultaneously. The waist radius, divergence and M²-factor of the semiconductor laser were obtained by measuring the beam images in different positions along propagation.