Comparison of numerical approaches to the evaluation of Veselago Lens' Green's function

Three approaches to numerical evaluation of two-dimensional Green's function under TM
_z
polarization are studied for the Veselago Lens of finite and infinite extent. The first approach formulates the Green's function of the infinite lens in terms of Fourier integral which is subsequently evaluated numerically via direct integration along a modified path. The second approach extracts the dominant field contribution near focus analytically with subsequent numerical treatment of the remaining faster converging Fourier integral term. The third approach is based on the method of moments solution of the integral equation formulated for the finite size lens. The methods are compared to each other for levels of resolution ranging from 0.077 down to 0.0312 wavelength.