lecture 1

Tips

• The content of these lectures is mainly reproduced from - “Laser Fundamentals” by William T. Silfvast
- “Laser Electronics” by JOSEPH T. VERDEYEN
• The content is just the broad lines of the lectures. Thus, not attending the lectures will lead to miss the main points of the course.
• Revising the lecture notes before coming to the class significantly increases the level of understanding the lecture.
• Re-deriving the math of the lecture gives great confidence at discussing the content and helps remembering the materials.
• Asking questions about the lecture can benefit you and all.













- What is the wave?
- What is the wavelength of a wave?
- What is the frequency of a wave?
- What is the phase of a wave?
- What is the photon?

Introduction
Laser
The word laser is an acronym that stands for "Light Amplification by Stimulated Emission of Radiation." (What is the stimulated emission?) A laser is a device that amplifies light and produces a highly directional (what does it mean?), high-intensity beam that most often has a very pure frequency or wavelength (what does it mean?). It comes in sizes ranging from approximately one tenth the diameter of a human hair to the size of a very large building, in powers ranging from 10-9 to 1018 W, and in wavelengths ranging from the microwave to the soft-X-ray spectral regions. Lasers have pulse energies as high as 104 J and pulse durations as short as < 5 x 10-15 sec (femtosecond) (what does it mean?).
A laser takes light that would normally be emitted in all directions, such as from a candle, and concentrates that light into a single direction. Thus, if the light radiating in all directions from a candle were concentrated into a single beam of the diameter of the pupil of your eye (approximately 3 mm), and if you were standing a distance of 1 m from the candle, then the light intensity would be 1,000,000 times as bright as the light that you normally see radiating from the candle! That is essentially the underlying concept of the operation of a laser.