Far-field sectioning for the retrieval of subwavelength grating parameters using coherent Fourier scatterometry

Optical inspection of periodic nanostructures is a major challenge in the semiconductor industry due to constantly decreasing critical dimensions. In this paper we combine coherent Fourier scatterometry (CFS) with a sectioning mask for subwavelength grating parameter determination. By selecting only the most sensitive regions of the scattered...

Ray-based methods for simulating aberrations and cascaded diffraction in imaging systems

To predict the quality of an optical system we need to simulate the effects of aberrations and diffraction. Aberrations can be calculated by tracing rays from a source point through a digital model of the system and evaluating the spot size of these rays on the detector. For a system without aberrations, the rays will intersect at a single point...

Ray tracing the Wigner distribution function for optical simulations

We study a simulation method that uses the Wigner distribution function to incorporate wave optical effects in an established framework based on geometrical optics, i.e., a ray tracing engine. We use the method to calculate point spread functions and show that it is accurate for paraxial systems but produces unphysical results in the presence...

Simulating multiple diffraction in imaging systems using a path integration method

We present a method for simulating multiple diffraction in imaging systems based on the Huygens–Fresnel principle. The method accounts for the effects of both aberrations and diffraction and is entirely performed using Monte Carlo ray tracing.We compare the results of this method to those of reference simulations for field propagation through...

A Wigner-based ray-tracing method for imaging simulations

The Wigner Distribution Function (WDF) forms an alternative representation of the optical field. It can be a valuable tool for understanding and classifying optical systems. Furthermore, it possesses properties that make it suitable for optical simulations: both the intensity and the angular spectrum can be easily obtained from the WDF and the...

Near-field optical reccording on cover protected discs

Near field optical data storage

This thesis describes research done at Philips Research on near-field optical data storage systems with a solid immersion lens.