Three Level Lasing System - Lasers and Fibre Optics - Engineering Physics 2

TL;DR

This video explains how a three-level lacing system leads to the formation of a laser through population inversion and coherent photon emission.

Transcript

click the bell icon to get latest videos from equator hello friends so in this video we are going to learn about a three level lacing system and how it leads to the formation of a laser in a laser assume that the lasing material is having three energy levels II 1 e 2 and E 3 where in a 1 is the ground state e 2 is the metastable state and III is th... Read More

Key Insights

• 🛝 A three-level lacing system consists of ground state, metastable state, and excited state in a lasing material.
• ✋ Population inversion is necessary for laser action and occurs when the higher energy states have more atoms than the ground state.
• 🥺 Coherent photons are emitted during the transition of atoms from the metastable state to the ground state, leading to laser formation.
• 🫀 Pumping is the process of energizing atoms and promoting them to the excited state, crucial for achieving population inversion.
• 🍰 The lifetime of the excited state is very short, while the metastable state has a longer lifetime, contributing to population inversion.
• ❓ Population inversion creates a favorable condition for stimulated emission to occur.
• ✋ A high-intensity laser is produced through the emission of coherent, monochromatic photons.

Questions & Answers

Q: What is a three-level lacing system?

A three-level lacing system refers to the energy levels in a lasing material, consisting of ground state (e1), metastable state (e2), and excited state (e3).

Q: What is population inversion?

Population inversion occurs when the number of atoms in the higher energy states (e2 and e3) exceeds the number of atoms in the ground state (e1), creating a favorable condition for stimulated emission.

Q: How does coherent photon emission occur?

Coherent photons are emitted when atoms in the metastable state (e2) fall to the ground state (e1), triggered by spontaneously emitted radiation photons. This emission results in a monochromatic, high-intensity laser.

Q: How does pumping in a three-level system work?

Pumping elevates atoms from the ground state (e1) to the excited state (e3) through an external energy source. This pumping process is essential for achieving population inversion.

Summary & Key Takeaways

• A three-level lacing system is discussed, consisting of ground state (e1), metastable state (e2), and excited state (e3) in lasing material.

• Pumping elevates atoms from e1 to e3, with a short lifetime, and they quickly jump to e2, which has a longer lifetime, causing population inversion.

• Coherent photons are emitted when atoms transition from e2 to e1, resulting in a high-intensity laser.