From e65df9cc33999cdd2f5926b10986bace815d8169 Mon Sep 17 00:00:00 2001 From: Claude Meny Date: Sat, 20 Mar 2021 10:12:26 +0100 Subject: [PATCH] Delete cheatsheet.en.md --- .../02.new-course-overview/cheatsheet.en.md | 148 ------------------ 1 file changed, 148 deletions(-) delete mode 100644 01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview/cheatsheet.en.md diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview/cheatsheet.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview/cheatsheet.en.md deleted file mode 100644 index 01105407e..000000000 --- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview/cheatsheet.en.md +++ /dev/null @@ -1,148 +0,0 @@ ---- -title: 'The thin lens' -media_order: 'Const_lens_conv_point_AapresO.gif,lens-convergent-N2-en.jpeg,Const_lens_conv_point_AentreFO.gif,lens-convergent-N2-es.jpeg,lens-convergent-N2-fr.jpeg,Const_lens_conv_point_AavantF.gif,lens-divergent-N2-es.jpeg,lens-divergent-N2-fr.jpeg,lens-divergent-N2-en.jpeg,diverging-thin-lens-representation.jpeg,converging-thin-lens-representation.jpeg' -published: true -visible: true ---- - -### What is a lens ? - -#### Objective - -* initial : to **focuse or disperse the light**. -* ultimate : to **realize images**, alone or as part of optical instruments. - -#### Physical principle - -* **uses the refractive phenomenon**, described by the Snell-Descartes' law. - -#### Constitution - -* Piece of **glass, quartz, plastic** (for visible and near infrared and UV). -* **Rotationally symmetrical**. -* **2 polished surfaces** perpendicular to its axis of symmetry, **either or both curved** (and most often spherical). - - - -#### Interest in optics : thin lenses - -* **Thin lens** : *thickness << diameter* -* Thins lens : **most important simple optical element** that is *used alone or combined in serie in most optical instruments* : magnifying glasses, microscopes, tele and macro objectives, camera, refracting telescopes. - - - -### Modeling a thin lens surrounded by air, gaz or vaccum. - -#### Why modeling ? - -* To **understand, calculate and predict images** of objects given by thin lenses - - - -##### Why surrounded by air, gaz or vaccum? - -* **In most optical instruments**, lenses are *surrounding by air*. -* **air, gaz and vaccum** have refractive index values in the range "$1.000\pm0.001$, and can be approximated by *$n_{air}=n_{gaz}=n_{vaccum}=1$*
-$\Longrightarrow$ same optical behavior in air, gaz and vacuum. - -#### Types and characterization of thin lenses - -**Convergent** = **converging** = **convexe** = **positive** lenses - -![](lens-convergent-N2-en.jpeg) - -* Characterized by :
-\- **Focal lenght** (usually in cm) always >0 *+* adjective "**converging**"
-  or
-\- Its **image focal length** $f'$ (in *algebraic value*, usually in cm), that is *positive $f'>0$*.
-  or
-\- Its **vergence** $V$ (in ophtalmology) that is *positive $V>0$*,
-with $V (\delta)=\dfrac{1}{f'(m)}$ ($f'$ being expresssed in m "meter" and $V$ in $\delta$ "dioptre", so $\delta=m^{-1}$).
- -**Divergent** = **diverging** = **concave ** = **negative** lenses - -![](lens-divergent-N2-en.jpeg) - -* Characterized by :
-\- **Focal lenght** (usually in cm) always >0 *+* adjective "**diverging**"
-  or
-\- Its **image focal length** $f'$ (in *algebraic value*, usually in cm), that is *negative $f'<0$*.
-  or
-\- Its **vergence** $V$ (in ophtalmology) that is *negative $V<0$*,
-with $V (\delta)=\dfrac{1}{f'(m)}$ ($f'$ being expresssed in m "meter" and $V$ in $\delta$ "dioptre", so $\delta=m^{-1}$).
- - - -### Analytical modeling - -(_for thin lens surrounded by air, gaz or vaccum_) - -##### Thin lens equation -**$\dfrac{1}{\overline{OA'}}-\dfrac{1}{\overline{OA}}=V=-\dfrac{1}{\overline{OF}}=\dfrac{1}{\overline{OF'}}$** - -##### Transverse magnification expression -**$M_{T-thinlens}=\dfrac{\overline{OA'}}{\overline{OA}}$** - - -### Graphical modeling - -#### Thin lens representation - -* **optical axis** = *revolution axis* of the lens, positively *oriented* in the direction of propagation of the light (_from the object towards the lens_). - -* **thins lens representation** :

-\- *line segment*, perpendicular to optical axis, centered on the axis with symbolic *indication of the lens shape* at its extremities (_convexe or concave_).

-\- **S = C = O** : vertex S = nodal point C = center O of the thin lens $\Longrightarrow$ is used point O.

-\- *point O*, intersection of the line segment with optical axis.

-\- *object focal point F* and *image focal point F'*, positioned on the optical axis symmetrically with respect to the point O ($f=-f'$) at algebraic distances $\overline{OF}=f$ and $\overline{OF'}=f'$.

-\- *object focal plane (P)* and *image focal plane (P')*, planes perpendicular to the optical axis at respectively points $F$ and $F'$. - -![](converging-thin-lens-representation.jpeg)
-_Converging thin lens representation : $\overline{OF}<0$ , $\overline{OF'}>0$ and $|\overline{OF}|=|\overline{OF'}|$_ - - ![](diverging-thin-lens-representation.jpeg)
- _Divverging thin lens representation : $\overline{OF}>0$ , $\overline{OF'}<0$ and $|\overline{OF}|=|\overline{OF'}|$_ - -#### Determining conjugate points : - -##### Converging thin lens - - - -* **Point source located between ∞ et F** - -![](Const_lens_conv_point_AavantF.gif) - -* **Point source located between F et O** - -![](Const_lens_conv_point_AentreFO.gif) - -* **Virtual object point** (will be seen at level foothills, to remove from here). - -![](Const_lens_conv_point_AapresO.gif) - -##### Diverging thin lens - -(to be implemented)