Second harmonic imaging of individual semiconductor nanostructures for scanning far field microscopy

A self-consistent approach for the solution of the Lippmann–Schwinger equations for both fundamental and second harmonic frequencies was used to calculate the field generated by a system at second harmonic (SH). The system consisting of a nonlinear parallelepiped object and nonlinear substrate was illuminated by Gaussian beam. The beam was scanned along the surface of the substrate. The object and substrate were supposed to have the nonlinearity corresponding to View the MathML source symmetry. It was assumed that the crystal axes of the object and substrate are rotated relative to parallelepiped axes of the object through 45°. The far-field SH images (the intensity of the field at a detector as a function of position of the center of Gaussian beam spot) were calculated numerically. The results of calculation were compared with experimental far-field images obtained by SH scanning optical microscopy for individual GaInP/GaAs nano-/micro-structures formed on a GaAs substrate. The images calculated in the work agree qualitatively with those obtained experimentally.