Physical optics

About: Physical optics is a research topic. Over the lifetime, 5342 publications have been published within this topic receiving 101388 citations. The topic is also known as: wave optics.

The Ultrasound Examination of the Hip

Abstract: The physical properties of ultrasound can be explained using the physical concepts of wave optics. The ultrasound wave propagates in the body along a straight path, similar to a beam of light. As in optics, the ultrasound wave is subject to processes of refraction and interference. Unlike light, sound requires a medium in which to propagate. It does so as a periodic fluctuation of density in the form of longitudinal waves; transverse waves also can occur in solid materials. The number of vibrations per second is measured in Hertz (Hz). Sound vibrating at frequencies up to 16 Hz is called infrasound. This range of frequencies is inaudible to the human ear, which can perceive frequencies only in the 16–20 Hz range. Frequencies above 20 Hz are called ultrasound. The velocity of sound in air is 0.3 km/s. Sound velocity increases in media of greater acoustic density, ranging from 1500 m/s in water to as much as 6000 m/s in iron.

Extreme Ultraviolet Lithography

Abstract: Master Extreme Ultraviolet Lithography Techniques Produce high-density, ultrafast microchips using the latest EUVL methods. Written by industry experts, Extreme Ultraviolet Lithography details the equipment, materials, and procedures required to radically extend fabrication capabilities to wavelengths of 32 nanometers and below. Work with masks and resists, configure high-reflectivity mirrors, overcome power and thermal challenges, enhance resolution, and minimize wasted energy. You will also learn how to use Mo/Si deposition technology, fine-tune performance, and optimize cost of ownership. Design EUVL-ready photomasks, resist layers, and source-collector modules Assemble optical components, mirrors, microsteppers, and scanners Harness laser-produced and discharge pulse plasma sources Enhance resolution using proximity correction and phase-shift Generate modified illumination using holographic elements Measure critical dimensions using metrology and scatterometry Deploy stable Mo/Si coatings and high-sensitivity multilayers Handle mask defects, layer imperfections, and thermal instabilities Table of contents Preface Chapter 1. Wigner Distribution in Optics Chapter 2. Ambiguity Function in Optical Engineering Chapter 3. Rotations in Phase Space Chapter 4. The Radon-Wigner Transform in Analysis, Design, and Processing of Optical Signals Chapter 5. Imaging Systems: Phase-Space Representations Chapter 6. Super Resolved Imaging in Wigner-Based Phase Space Chapter 7. Radiometry, Wave Optics, and Spatial Coherence Chapter 8. Rays and Waves Chapter 9. Self-Imaging in Phase Space Chapter 10. Sampling and Phase Space Chapter 11. Phase Space in Ultrafast Optics Index

An Introduction to Weakly Nonlinear Geometrical Optics

Abstract: Many natural phenomenae are governed by systems of nonlinear conservation laws that are — in a first approximation — hyperbolic. In this context, the understanding of the laws governing the propagation and interaction of small but finite amplitude high frequency waves in hyperbolic P.D.E.’s, and their interactions with “large scale” phenomenae (mean flows, shear layers, shock and detonation waves, etc.) is very important. Weakly Nonlinear Geometrical Optics (W.N.G.O.) is an asymptotic formal theory whose objective is precisely to do this.

Vectorial ray-based diffraction integral.

Abstract: Laser interferometry, as applied in cutting-edge length and displacement metrology, requires detailed analysis of systematic effects due to diffraction, which may affect the measurement uncertainty. When the measurements aim at subnanometer accuracy levels, it is possible that the description of interferometer operation by paraxial and scalar approximations is not sufficient. Therefore, in this paper, we place emphasis on models based on nonparaxial vector beams. We address this challenge by proposing a method that uses the Huygens integral to propagate the electromagnetic fields and ray tracing to achieve numerical computability. Toy models are used to test the method's accuracy. Finally, we recalculate the diffraction correction for an interferometer, which was recently investigated by paraxial methods.

Sideways adiabaticity: beyond ray optics for slowly varying metasurfaces

Abstract: Optical metasurfaces (subwavelength-patterned surfaces typically described by variable effective surface impedances) are typically modeled by an approximation akin to ray optics: the reflection or transmission of an incident wave at each point of the surface is computed as if the surface were “locally uniform,” and then the total field is obtained by summing all of these local scattered fields via a Huygens principle. (Similar approximations are found in scalar diffraction theory and in ray optics for curved surfaces.) In this paper, we develop a precise theory of such approximations for variable-impedance surfaces. Not only do we obtain a type of adiabatic theorem showing that the “zeroth-order” locally uniform approximation converges in the limit as the surface varies more and more slowly, including a way to quantify the rate of convergence, but we also obtain an infinite series of higher-order corrections. These corrections, which can be computed to any desired order by performing integral operations on the surface fields, allow rapidly varying surfaces to be modeled with arbitrary accuracy, and also allow one to validate designs based on the zeroth-order approximation (which is often surprisingly accurate) without resorting to expensive brute-force Maxwell solvers. We show that our formulation works arbitrarily close to the surface, and can even compute coupling to guided modes, whereas in the far-field limit our zeroth-order result simplifies to an expression similar to what has been used by other authors.