Photonics

Photonics is a field of study focused on light, in both its wave and particle forms. Photonic solutions are indispensable in countless fields, such as ultra-high-speed telecommunications, medicine, aerospace, lighting, the environment (observation, treatment), defense (night vision, guidance), metrology, and more. As part of the EEA bachelor’s degree program and this module—which combines practical (lab) and theoretical (lecture/tutorial) components—the fundamentals of electromagnetism will be covered, including the equation of propagation for an electromagnetic wave, the properties of these waves, and their behavior at interfaces. This will lead to the study of key phenomena in wave photonics in particular, such as diffraction and interference, which will provide an understanding of how to use light for spectroscopic analysis, to measure deformations, to encode information for very high-speed communications, to store information, and more.

The objectives of this module are, first and foremost, to be able to describe electromagnetic waves and understand how they behave, by applying Maxwell’s equations and common differential operators.

The next step is to understand the phenomena of diffraction and interference, in order to acquire the knowledge necessary for implementing interferometers in common photonic applications such as spectroscopy, communications, and strain measurements.

knowledge of waves (acoustics, microwaves, or other types).

Recommended prerequisites: knowledge of geometric optics.

1. I. Electromagnetic Waves (Lecture 7.5 hours - Lab 3 hours)
2.  Reminders
3. Vector operators
4. Basic Relationships in Electrostatics and Magnetostatics, Fields, and Sources
5. Harmonic Model of a Plane Wave
6. Maxwell's Equations
7. Historical Background
8. Description of Maxwell's Equations
9. Link Between EMs and Static Relationships
10. Expression of EMs in harmonic mode
11. Propagation of the Electromagnetic Field
12. Structure of the Electromagnetic Field
13. Propagation in a vacuum, propagation equation
14. (Potential Propagation)
15. In LHI circles
16. Transient relationships at the interface
17. Polarization
18. The Concept of Light Polarization
19. Malus's Law
20. Reflection/Transmission at the Interface
21. (Fresnel's equations)
22. Electromagnetic energy
23. Energy carried by an electromagnetic wave
24. Poynting vector
25. Mean Value of the Poynting Vector and Applications

1. II. Interference & Diffraction (Lecture 7.5 hours - Lab 3 hours)
2. Introduction: Interference & Diffraction (1 hour 30 minutes)

            1.1 Huygens-Fresnel Principle

            1.2 Different Types of Interference (Steady-State, Transient)

1. a) Description of light and formalism
2. (b) Monochromatic interference
3. c) Instantaneous interference (beating)
4. d) Interference between counter-propagating waves: longitudinal standing wave

            1.3 Typical Approach to Studying Interference and Diffraction

1. a) Step difference and phase shift
2. b) Sum of the electric fields
3. c) Measurement of optical intensity
4. Interference (3 hours)

            2.1 Two-Wave Interference

1. a) Michelson interferometer
2. b) Transfer function of a two-wave interferometer
3. (c) Polychromatic interference 

            2.2 N-Wave Interference

1. (a) Fabry-Perot cavity
2. b) Airy function
3. c) Fabry-Perot with gain (laser)

            2.3 Other Commonly Used Interferometers & Applications

1. Diffraction (3 hours)

            3.1 Near Field & Far Field

            3.2 Diffraction through a slit in the far field

            3.3 Fourier Transform in the Far Field

            3.4 Diffraction Through a Hole

            3.5 Young's Slits

            3.6 Diffraction Grating

III. PRACTICAL WORK (12 hours)

            Assignment 1: Polarization & Diffraction of Light

            TP2. Mach-Zehnder amplitude modulator for optical communications

            TP3. Grating Spectrometer

            TP4. Detection of Weak Optical Signals