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Contents. IntroductionThe essence of nonlinear opticsSecond order nonlinear phenomenaThird order nonlinear phenomena Nonlinear optical materialsApplications of nonlinear optics. Introduction. Question: Is it possible to change the color of a monochromatic light?Answer: Not without a lase
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1. Introduction to Nonlinear Optics H. R. Khalesifard
Institute for Advanced Studies in Basic Sciences
Email: khalesi@iasbs.ac.ir
2. Contents Introduction
The essence of nonlinear optics
Second order nonlinear phenomena
Third order nonlinear phenomena
Nonlinear optical materials
Applications of nonlinear optics
3. Introduction Question:
Is it possible to change the color of a monochromatic light?
Answer:
Not without a laser light
4. Stimulated emission, The MASER and The LASER (1916) The concept of stimulated emission Albert Einstein
(1928) Observation of negative absorption or stimulated emission near to resonant wavelengths, Rudolf Walther Ladenburg
(1930) There is no need for a physical system to always be in thermal equilibrium, Artur L. Schawlow
7. The Maser Two groups were working on Maser in 50s
Alexander M. Prokhorov and Nikolai G. Bassov (Lebedev institute of Moscow)
Charles H. Townes, James P. Gordon and Herbert J. Zeiger (Colombia University)
8. Left to right: Prokhorov, Townes and Basov at the Lebede institute (1964 Nobel prize in Physics for developing the “Maser-Laser principle”)
9. Townes (left) and Gordon (right) and the ammonia maser they had built at Colombia University
10. The LASER (1951) V. A. Fabrikant “A method for the application of electromagnetic radiation (ultraviolet, visible, infrared, and radio waves)” patented in Soviet Union.
(1958) Townes and Arthur L. Schawlow, “Infrared and Optical Masers,” Physical Review
(1958) Gordon Gould definition of “Laser” as “Light Amplification by Stimulated Emission of Radiation”
(1960) Schawlow and Townes U. S. Patent No. 2,929,922
(1960) Theodore Maiman Invention of the first Ruby Laser
(1960) Ali Javan The first He-Ne Laser
11. Maiman and the first ruby laser
12. Ali Javan and the first He-Ne Laser
13. Properties of Laser Beam A laser beam
Is intense
Is Coherent
Has a very low divergence
Can be compressed in time up to few femto second
14. Applications of Laser (1960s) “A solution looking for a problem”
(Present time) Medicine, Research, Supermarkets, Entertainment, Industry, Military, Communication, Art, Information technology, …
15. Start of Nonlinear Optics Nonlinear optics started by the discovery of Second Harmonic generation shortly after demonstration of the first laser.
(Peter Franken et al 1961)
16. 2. The Essence of Nonlinear Optics When the intensity of the incident light to a material system increases the response of medium is no longer linear
17. Response of an optical Medium The response of an optical medium to the incident electro magnetic field is the induced dipole moments inside the medium
18. Nonlinear Susceptibility The general form of polarization
19. Nonlinear Polarization Permanent Polarization
First order polarization:
Second order Polarization
Third Order Polarization
20. How does optical nonlinearity appear The strength of the electric field of the light wave should be in the range of atomic fields
21. Nonlinear Optical Interactions The E-field of a laser beam
2nd order nonlinear polarization
22. 2nd Order Nonlinearities The incident optical field
Nonlinear polarization contains the following terms
23. Sum Frequency Generation
25. Phase Matching
26. SHG Experiments We can use a resonator to increase the efficiency of SHG.
28. Third Order Nonlinearities When the general form of the incident electric field is in the following form,
The third order polarization will have 22 components which their frequency dependent are
29. The Intensity Dependent Refractive Index The incident optical field
Third order nonlinear polarization
34. Processes due to intensity dependent refractive index Self focusing and self defocusing
Wave mixing
Degenerate four wave mixing and optical phase conjugation
35. Self focusing and self defocusing The laser beam has Gaussian intensity profile. It can induce a Gaussian refractive index profile inside the NLO sample.
36. Wave mixing
37. Optical Phase Conjugation Phase conjugation mirror
38. Aberration correction by PCM
39. What is the phase conjugation
40. Degenerate Four Wave Mixing
41. Mathematical Basis
42. Holographic interpretation of DFWM