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@ -2,4 +2,42 @@ |
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title: 'new course : overview' |
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--- |
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new course : overview |
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### The mirror |
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#### What is a mirror ? |
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##### Objective |
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* initial : to **reflect** light, to **focus or disperse light**. |
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* Ultimate : to **realize images**, alone or as part of optical instruments. |
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##### Physical principle |
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* uses the **phenomenon of reflection**, described by the law of reflection. |
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##### Constitution |
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* Usually plane or curved (spherical for the most simple to realize, |
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parabolic or elliptical) **surface, highly polished** so that its surface |
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state deviates from its theoretical form of less than $`\lambda/10`$ at each point |
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of its surface ($`\lambda`$ being the wavelength in vacuum of the light to be reflected). |
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To increase the reflectivity of the mirror (percentage of reflected light |
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intensity per the total of the incident light intensity), the surface is |
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**most often metallized**. |
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##### Interest in optics |
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* **One of the most importante simple optical component** that is used *alone or |
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* combined in a series in most optical instruments* : some telephotos, |
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* reflecting telescopes. |
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#### Why to study plane and spherical mirrors? |
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* **Plane and spherical mirrors** are the *most technically easy to realize*, |
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so they are the *most common and cheap*. |
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* In paraxial optics, the optical properties of a **plane mirror** are those |
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of a *spherical mirror of infinite radius of curvature*. |
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Plane mirror, concave and convex spherical mirror |
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