Optics Geometric Optics1 CHAPTER 2 GEOMETRIC OPTICS

Every ray from O to I requires the same transit time  isochronous. The point O is the conjugate of point I. In an ideal system, every ray from O pass through I. Practical systems are non-ideal due to: 1.Scattering  dimming 2.Aberrations  distortion; no 1-to-1 relationship 3.Diffraction  sharpness (diffraction limited) Optics Geometric Optics2 Imaging by an optical system

Optics Geometric Optics3 Reflection at a Spherical Surfaces

Optics Geometric Optics4 Thin Lenses Lensmaker’s equation

Optics Geometric Optics5 Reflection at a Spherical Surfaces Reflection (Mirrors)Refraction (lenses) CasesConvexConcaveConvergingDiverging Case 1 V-U-SV-U-L V-U-S Case 2 V-U-SR-I-L V-U-S Case 3 V-U-SR-I-S V-U-S

Optics Geometric Optics6 Reflection at a Spherical Surfaces

Optics Geometric Optics7 Refraction at a Spherical Surfaces

Optics Geometric Optics8 Refraction at a Spherical Surfaces Starting from Snell’s law What happens when R   ?

Optics Geometric Optics9 Refraction at a Spherical Surfaces Example..

Optics Geometric Optics10 Vergence and Refractive Power When distance is measured in meters.. The refracting power is measured in diopters

Optics Geometric Optics11 Vergence and Refractive Power When two thin lenses are in direct contact

Optics Geometric Optics12 Newtonian Equation for the Thin Lens

Optics Geometric Optics13 Cylindrical Lenses Spherical Lens (stigmatic) Cylindrical Lens (astigmatic)

Optics Geometric Optics14 ABERRATION Spherical

Optics Geometric Optics15 ABERRATION Coma

Optics Geometric Optics16 ABERRATION Astigmatism Circle of least confusion

Optics Geometric Optics17 ABERRATION Field curvature

Optics Geometric Optics18 ABERRATION Distortion Angular deviation of the wavefront destroying the linear relation between dimensions in object and image

Optics Geometric Optics19 THE INFLUENCE OF APERTURE STOPS Images can be improved by stops Distortion can be controlled by the correct positioning of the aperture stops

Optics Geometric Optics20 THE CORRECTION OF CHROMATIC ABERRATION Chromatic aberration: The spread of an image point over a range of colors The power of a refracting surface depends on the wavelength WHY ?? Can be compensated for by combining lenses made of different materials