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OSE 6334 Nonlinear Optics Konstantin Vodopyanov 1 1 Lecture 1 Introduction to nonlinear optics. Logistics. 2 2 1 What this course is about This course gives a broad introduction to the field of Nonlinear Optics (NLO). The goal is to get you acquainted with the main effects of nonlinear optics and also introduce main equations that govern nonlinear-optical interactions. Beginning with a simple electron on a spring model—the course gives comprehensive explanations of second-order and third-order nonlinear effects and their physical origins. The corse covers nonlinear optics from a combined: physics, optics, materials science, and devices perspective. Examples will be given on solving practical problems such as design of nonlinear frequency converters, and also devices using ultrafast and high intensity lasers. 3 3 Newton’s superposition principle f(A+B) = f(A) + f(B) B Isaac Newton 1642 –1726 A Newton: Light cannot interact with light. Two beams of light can have no effect on each other. 4 4 2 Nonlinear optics f(A+B) ≠ f(A) + f(B) Beams A and B can create beam C Nicolaas Bloembergen B 1920–2017 Nobel Prize in Physics (1981) C A NLO: photons do interact 5 5 Linear Optics • The optical properties such as the refractive index and the absorption coefficient are independent of light intensity. • The Newton’s principle of superposition: light cannot interact with light. Two beams of light in the same region of a linear optical medium can have no effect on each other. Thus light cannot control light. • The frequency of light cannot be altered by its passage through the medium. Nonlinear Optics • The refractive index, and consequently the speed of light in an optical medium does change with the light intensity. • The absorption coefficient does change with the light intensity. • The principle of superposition is violated. Light can control light; photons do interact. • Light can alter its frequency as it passes through a nonlinear optical crystal, e.g. from red to blue and vice versa. NLO - many fascinating phenomena ! 6 6 3 What is the outcome of this course You will be able to: Understand modern literature on lasers and their nonlinear optical applications Distinguish between 2-nd-order and 3-rd-order nonlinear-optical effects Do back-of-the-envelope NLO calculations Explore NLO effects on your own 7 7 Topics to be studied • Refreshing math basics. Linear electrodynamics. • Slowly varying envelope approximation • Nonlinear susceptibility of a classical anharmonic oscillator • Quantum-mechanical perturbation theory for the nonlinear optical susceptibility • Coupled-wave equations in nonlinear optics • Sum-frequency and second-harmonic generation • Second-order (χ(2)) nonlinear optical materials • Phase matching in nonlinear optics • Quasi-phase-matching (QPM) • Second-harmonic generation inside a resonator cavity • Difference-frequency generation • Optical parametric oscillators (OPO) and amplifiers (OPA) • OPO tuning curves and bandwidth • Conversion efficiency of nonlinear optical processes • Frequency conversion using femtosecond optical pulses • Third-order (χ(3)) nonlinear effects • Kerr effect. Intensity-dependent refractive index • Self-focusing. Self-phase modulation • Third harmonic generation. Parametric processes due to the 4-wave mixing • Phase conjugation, optical limiting, all-optical switching • Techniques for measuring second- and third-order nonlinearities; Z-scan • Nonlinear phase shift due to cascaded χ(2) effects • Stimulated Raman and Brillouin scattering • Modern examples: Two- and three-photon microscopy, high-field interactions 8 8 4 Schedule 9 9 Schedule 10 10 5 Home works Assignment: Once a week (on Wednesday) Home work report: submit via Webcourses before Sunday night (11:59pm) 11 11 Mid-term exam Oct 21 2019, Monday, 1:30–2:45 pm Open book, ~ 10 problems 12 12 6 Final exam Dec 9 2019, Monday, 1:00–3:50 pm In the form of 10-min students’ presentation (~ 10 slides) Sources: § Articles from different journals: Scientific American, Nature, Science, Optica, Optics Letters, New York Times, etc .... ... § Can also be an original (experimental or theoretical) project of your choice 13 13 Grades 14 14 7 Texbooks 1. R. W. Boyd, Nonlinear Optics, 3rd Edition, (Academic Press, 2008). These are two main textbooks. Boyd is easier to read than Stegeman, although Boyd has some unconventional definitions; Stegeman has more 2. G. I. Stegeman, R. A. Stegeman, Nonlinear Optics: Phenomena, formalism, but gives nice physical models for different } NLO effects Materials and Devices, (Wiley 2012) 3. Y. R. Shen, The Principles of Nonlinear Optics (Wiley 2003) nice book, but heavier formalism than in other books 4. B. E. A. Saleh and M. C. Teich, Fundamentals of Photonics (Wiley NLO chapter – very clearly written 2007) 5. A. Yariv, Quantum Electronics (Wiley 1989) nice chapters on quantum mechanics for NLO - these are books that I used 15 15 Lecture notes The lecture notes will be placed on Webcourses as the course progresses. For example, notes for a coming lecture will be placed no later than the night before. 16 16 8 Lecture Capture. Panopto Lecture Capture – all classes will be video recorded. Panopto – a software that does lecture recording, screencasting, video streaming, and video content management. 17 17 You can interrupt me any time during a lecture if you have questions Any questions right now ? 18 18 9.
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