3-D light distribution within the focused spot by large aperture objectives for optical data storage

Since its emergence in early 1970s, optical disk has been playing a main role in data storage. The most attractive features of the optical disk such as high information density and large storage capacity are all made possible by the large aperture recording objective. As the aperture of the objective increases, however, one problem arises in studying the exact light distribution within the focused spot--the conventional scalar diffraction theory would introduce intolerable error to the results. Therefore, the vectorial properties of light must be taken into consideration. For this purpose, we developed 3-D optical diffraction integrals for focusing optical systems with a different method from those used by H. Hopkins AND B. Richards and E. Wolf. This method is simple and has proved effective in dealing with systems with and without aberrations.