Presentation on theme: "Optics and Photonics Selim Jochim together with Dr. K. Simeonidis MPI für Kernphysik und Uni Heidelberg"— Presentation transcript:
Optics and Photonics Selim Jochim together with Dr. K. Simeonidis MPI für Kernphysik und Uni Heidelberg Website for this lecture: teaching
What will you learn in this course? How to use advanced photonics instruments and technology in the laboratory Learn to develop your own ideas on how to make use of photonics for (precision) experiments Knowlegde that is widely needed in many labs in Heidelberg: –Biomedical research –Laser spectroscopy –High-power ultrafast lasers for atomic physics –Laser cooling and trapping, (quantum) manipulation of atoms, molecules or ions
Motivation We make (increasingly) heavy use of photonics in our daily life. Two interesting examples: Green laser pointers emit bright light at 532 nm: How are they made? make use of almost anything you will learn in this course!! DVD reader/writer ( resolution of a microscope for a few !!)
Contents II More lasers, solid state lasers, dye lasers, etc Pulsed lasers: Q-switching, mode locking, extremely short pulses Semiconductor photonics: detectors, LEDs, Lasers Fourier optics, holography Nonlinear optics concepts 4.7.Nonlinear optics applications: Frequency doubling, mixing Advanced applications: Frequency comb, optical synthesizer Lab tour(s)
Recommended literature Saleh, Teich: Fundamentals of Photonics Kneubühl, Sigrist: Laser Davis: Lasers and Electro-Optics: Fundamentals and Engineering Demtröder: Laserspektroskopie Hecht, Optics (Especially for the first few lectures)
1. Geometric (ray) optics Light propagates as rays with speed of light, c in vacuum In a medium, the light is slowed down by the refractive index n In an inhomogeneous system, propagation is governed by Fermats principle: Minimize optical path length:
Fermats principle Phenomenologically: Hero of Alexandria (ca. 70 – 10 A.D.): Light always takes the shortest path when reflected from a surface:
Refraction A B
Interfaces between dielectrics … n2>n1 … Total internal reflection …. critical angle:
Where total internal reflection is used Prisms, e.g. binoculars, camera viewfinder Optical fibers:
Parabolic mirror Parallel beams are focused onto a single spot: Car headlight!
Spherical mirror, paraxial rays Paraxial rays: Assume that all beams propagate close to optical axis. In most cases, this means that sin tan Rays are focused to F=R/2
Imaging with spherical mirrors
Paraxial imaging Magnification
Matrix formalism for parax. rays Use it to describe a complex optical system with a single (2,2)-matrix Define state of a ray by a 2-comp. vector: valid if
Example matrices Free space propagation Refraction at a surface
Optical system ….
When the paraxial approx. fails … Focussing of a laser beam: Minimize non-paraxial distortions: Plano-convex lens, also best form lens
Spherical aberration … Can we make all parallel rays incident on a lens end up in a single spot??
Aspheric lens? Optical path length should be the same for all angles ….
Aspheric lenses All kinds of quality grades available Molded, plastic material
Precision machined … ASPHERIC LIMITS STANDA RD HIGH PRECISIO N Diameter (mm) Length (mm) Width (mm) Dimensional Tolerances (µm) 255 Center Thickness Tolerance (µm) Wedge Tolerance (µm) 7525 Surface Quality Radius Limits (mm) LRC Limited Concave >30.0 Convex >5.0 Radius Tolerance (%) Total SAG (mm) <25 Aspheric Surface Accuracy (wave) 1/41/10