Geometrical Optics
Ray optics approximation, specular reflection, planar and spherical mirrors, and thin lenses.
General idea of the topic
Geometrical optics models light as rectilinear rays to predict trajectories and images at interfaces, mirrors, lenses and optical instruments, within the regime where wavelength is negligible.
It applies angular laws of reflection and refraction combined with paraxial image-formation equations, identifying the type, position and magnification of each image produced.
What you will truly understand
- How to use angular laws at flat and curved surfaces.
- How to decide image type, position and magnification.
- How to connect paraxial equations with limits of validity.
Recommended learning route
- Reflection.
- Refraction (Snell's law and refractive index).
- Mirrors and lenses.
- Optical instruments.
Physical criterion you must acquire
Do not mix sign conventions and always verify coherence between calculation and ray diagram.
Connection with real problems
Cameras, spectacles, telescopes, microscopes, light guiding and optical metrology.
Final goal of the topic
Solve image formation problems with mastery of equations and geometric criterion.
Topics in this section
- Reflection (Geometrical Optics)
Laws of light reflection on flat and curved surfaces, angles of incidence and reflection.
- Refraction (Geometrical Optics)
Snell's law of refraction, refractive index, chromatic dispersion, and total internal reflection.
- Mirrors
Image formation by reflection from flat and spherical surfaces, including the mirror equation and lateral magnification.
- Lenses
Real and virtual image formation through thin converging and diverging lenses.
- Optical Instruments
Image formation and angular magnification in magnifying glass, compound microscope and refracting telescope.