Topic
Total external reflection
About: Total external reflection is a research topic. Over the lifetime, 829 publications have been published within this topic receiving 22213 citations.
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TL;DR: In this paper, the authors applied grazing incidence X-ray photoemission spectroscopy to the determination of the thickness of SiO2 layers on Si, as well as surface carbon that is present.
12 citations
TL;DR: In this article, the authors show that there is no real limit on the numerical aperture into a material, as long as its extinction coefficient is not zero, assuming that the contribution of the imagined component of the refractive index is negligible.
Abstract: As immersion lithography is extended to ever increasing resolution, the resulting propagation angles in the
materials involved become closer to grazing than to normal incidence. Classical laws of refraction and reflection cannot
be used with either assumption however, as a collection of angles may exist across the entire range. Fresnel reflection at
these angles becomes large enough that small disparities in refractive indices at material interfaces may lead to adverse
effects. As an example, when water is used at numerical apertures approaching its refractive index, reflection effects are
greater than the constraints imposed by refraction or absorption. This will limit the maximum NA value allowed by any
given material to values sufficiently lower than its refractive index. Additionally, we have grown accustom to expanding
the application of the Snell-Descartes Law to materials with low absorption, assuming that the contribution of the
imaginary component of the refractive index is negligible. This is not the case for photoresists, fluids, or glasses, which
can not strictly be considered as non-absorbing media. We have expanded the Snell-Descartes Law for absorbing media,
with some interesting consequences. We will show that there is no real limit on the numerical aperture into a material,
so long as its extinction coefficient is not zero. The relationship that lithographers have been using recently where NA<
min[n glass , n fluid , n resist ] will be shown to be inadequate and imaging at numerical apertures up to 1.85 will be demonstrated
using materials with significantly lower (real) refractive index values.
12 citations
Patent•
16 Jul 1996
TL;DR: In this paper, a basic reflection surface is formed by preliminarily setting a basic surface on which multiple paraboloids are to be formed, under a setting condition, and if the result of the preliminary setting is good, the setting condition is changed to another or other setting conditions, and the step of preliminary setting and evaluation of the incident angle distribution are repeated under the changed setting condition or conditions.
Abstract: A method of forming a reflection surface of a reflection mirror of a vehicle lamp includes the following steps. A basic reflection surface is formed by preliminarily setting a basic reflection surface on which multiple paraboloids are to be formed, under a setting condition. Angles θ at which light that is emitted from a light source located at a focal point is incident on different positions on the basic reflection surface, are calculated, to thereby form a plural number of contours of equal incident angles on the basic reflection surface. A distribution of incident angles is evaluated on the basis of the contours of equal incident angles. If the result of the evaluation is good, the basic reflection surface is set as a final basic reflection surface. If it is no good, the setting condition is changed to another or other setting conditions, and the step of the preliminary setting and the step of the evaluation of the incident angle distribution are repeated under the changed setting condition or conditions. Through those steps, a basic reflection surface can reliably be set which has an incident angle distribution excellent in suppressing the generation of dark portions on the reflection surface to the minimum and at the same time securing a required solid angle of the reflection mirror.
12 citations
TL;DR: In this paper, a critical angle method was used to measure the index of refraction of a solid medium when an air gap between the prism and the medium is present, and the gap effect was analyzed both numerically and experimentally.
Abstract: A critical angle method was used to measure the index of refraction of a solid medium when an air gap between the prism and the medium is present. The gap effect was analyzed both numerically and experimentally. Since the total internal reflection is severely disturbed by the large gap, determination of the critical angle and the resulting refractive index becomes ambiguous and inaccurate. By using an index matching fluid, we could determine the index of refraction with an uncertainty of ${\pm}2{\times}1^{-3}$ even when the gap is as large as 1 ${\mu}m$ .
12 citations
TL;DR: In this paper, the authors considered the transmission and reflection of light by a layered medium where the optical index of every layer is a constant which fluctuates from one layer to another, and they found that in the limit of a very large number of layers, the transmission coefficient vanishes exponentially, and the medium becomes an ideal reflector.
Abstract: We consider the transmission and reflection of light by a layered medium where the optical index of every layer is a constant which fluctuates from one layer to another. In the limit of a very large number N of layers, the transmission coefficient vanishes exponentially, and the medium becomes an ideal reflector. A new simple method is used to evaluate the penetration depth ξ for normal incidence and at the critical angle for total reflection of the homogeneous equivalent medium. For a Gaussian distribution with width ζ of the fluctuating part of the index, we find ξ∼ζ −2 and ξ c ∼ζ −2/3 , respectively. We also discuss the properties of the reflection coefficient and show computer simulations. We expect our results to be also valid for neutron transmission Evaluation de la longueur de penetration a l'incidence normale et pour l'angle critique de reflexion totale du milieu homogene equivalent
12 citations