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...

Methods for optical modeling and cross-checking in ellipsometry and scatterometry

Spatial mode projection for side-wall angle measurements

Finding a fast and precise method to measure the side-wall angle of periodic (or non-periodic) structures is still a very challenging problem in lithographic applications. For this reason, over the years, many techniques have been proposed to circumvent this limitation, with the final goal to give the most precise geometrical description of...

Experimental demonstration of phase retrieval from a single defocused intensity measurement in the approximation of small aberrations

We analytically demonstrate that Phase Retrieval (PR) from defocused intensity measurements is achievable using a single measurement plane. Following this approach, the predicted plane is found at a defocus distance of 4? optical unit. Experimental results confirm the theoretical predictions

A numerical model for super resolution effect in optical discs

A simplified computational model for super resolution effect in optical discs is proposed and simulations are compared with experimental results, providing basic understanding of this phenomenon. Simulations show that resolution beyond the diffraction limit is achieved and signal destruction occurs at some frequencies when the super resolution...

On maximum field components in the focal point of a lens

We determine field distributions in the pupil of a high NA lens, that give, for a given power incident on the lens, the maximum electric field amplitude in focus in a specific direction. We consider in particular the cases of maximum longitudinal and maximum transverse components. The distribution of the maximum longitudinal component in the...

Ray-tracing simulations and applications of liquid crystal beam control devices

Correlation functions formed by a femtosecond pulse interferometer

We experimentally demonstrate that a stabilized femtosecond frequency comb can be applied as a tool for distance measurement. The scheme is based on optical interference between individual pulses in a Michelson type interferometer. The cross-correlation functions between individual pulses with a distance of around 15 meter and 30 meter are...

Theoretical study of long distance measurement using frequency comb laser

Frequency and distance metrology have been revolutionized with the arrival of stabilized frequency comb lasers. We discuss several aspects of distance metrology specially the contribution of the dispersion in by air.

General imaging of advanced 3D mask objects based on the fully-vectorial Extended Nijboer-Zernike (ENZ) theory

In this paper we introduce a new mask imaging algorithm that is based on the source point integration method (or Abbe method). The method presented here distinguishes itself from existing methods by exploiting the through-focus imaging feature of the Extended Nijboer-Zernike (ENZ) theory of diffraction. An introduction to ENZ-theory and its...

Extended Nijboer-Zernike (ENZ) based mask imaging: Efficient coupling of electromagnetic field solvers and the ENZ imaging algorithm

Results are presented of mask imaging using the Extended Nijboer-Zernike (ENZ) theory of diffraction. We show that the efficiency of a mask imaging algorithm, derived from this theory, can be increased. By adjusting the basic Finite Difference Time Domain (FDTD) algorithm, we can calculate the near field of isolated mask structures efficiently,...

3D Rigorous simulation of mask induced polarization

The polarization induced by the mask is studied by using a 3D rigorous model, wich solves Maxwell equations using the finite element method. Teh aerial image depends strongly on the change of polarization induced by the materials, thickness of the layer and pitch of the periodic masks.

Wavefront measurement for EUV lithography system through Hartmann sensor

Accurate wavefront aberration measurement are essential for next-generation Extreme Ultraviolet (EUV) Lithography. During the past years several accurate interferometric techniques have been developed, but these techniques have limitation. In this work we discuss a different technique based on the Hartmann Wavefront Sensor that requires no...