Starting from an understanding of basic interactions of light and maters known as spontaneous emission and induced emission, the instructor explains principle of a laser that consists of inverted population and an optical resonator. The instructor introduces the concept of coherence, which is very useful for characterizing the properties of laser light, and makes clear the difference with ordinary light. Then the instructor will explain the coherent state of a mater formed as a result of interaction with coherent light. We finally go over the features of many types of lasers, and classify them to introduce real, applied examples.
After understanding of an optical resonator combined with the spatial mode, population inversion in matter, amplification process of light in the laser media, generation of ultra-short pulse, students are expected to recognize the difference between laser light and ordinary light by using the idea of coherence. Students will also gain an understanding of the operating principles and features of several kinds of lasers, acquiring knowledge about their applications.
spatial mode, spontaneous emission, induced emission, optical resonator, population inversion, coherence, ultra-short pulse
|Intercultural skills||Communication skills||Specialist skills||Critical thinking skills||Practical and/or problem-solving skills|
A lecture note with several blanks is provided in advance. Instead of black board, descriptions are directly written on screen by a pen tablet computer. Hearing the explanation, students fill in the blanks and complete the lecture note.
|Course schedule||Required learning|
|Class 1||laser light and ordinary light||directivity,monochromaticity,ultra-short pulse, brightness|
|Class 2||Absorption and emission of light||Einstein’s theory of spontaneous and induced emission|
|Class 3||principle of the laser||population inversion and optical resonator|
|Class 4||Laser amplification and oscillation condition||Gain factor and loss Three-level system, four-level system|
|Class 5||Output characteristics of the laser||rate equation of laser oscillation|
|Class 6||Continuous wave and ultra-short pulse laser||Q-switching and mode locking|
|Class 7||The coherence of light||time and space coherence|
|Class 8||Coherent interaction with ensemble of atoms and molecules||density matrix, T1 and T2 relaxation processes|
lecture note with blanks is distributed.
Introduction to laser physics, Koich Shimoda, Iwanami.
Thequantum theory of light, Loudon, Oxford.
Learning achievement is evaluated by weekly reports and a final exam.