How Is a Laser Made?

What makes laser light so different from a light bulb? discover the quantum physics behind lasers, and the materials that give each laser its color, from the first ruby laser of 1960 to modern semiconductor diodes. In this video: ⚛️ Energy levels: absorption and spontaneous emission ✨ Stimulated emission: Einstein’s 1917 prediction, where one photon becomes two identical photons 🔋 Population inversion: pumping, 3- and 4-level systems and the metastable level 🪞 The optical cavity: mirrors, amplification and the output beam 💎 Solid-state lasers: ruby (Cr³⁺:Al₂O₃, 694 nm), Nd:YAG (1064 nm), Ti:sapphire (tunable, femtosecond) 💨 Gas lasers: helium-neon (633 nm), argon, CO₂ (10.6 µm) 💡 Semiconductor and fiber lasers: GaAs, AlGaInP, InGaN diodes, and Yb- or Er-doped fibers 🌈 The material sets the color: E = hc/λ 🏭 Applications: industry, medicine, telecom, lidar and research Ideal for university students in physics, materials science, optics and engineering. 👍 Like, subscribe and share for more videos from Materials Science Secrets! 📷 Photo credits (Wikimedia Commons): Laser beams: 彭家杰, CC BY-SA 3.0 Ruby laser rod / laser rods: Artem.G, CC BY-SA 4.0 Ti:sapphire crystal: Mathieu Perrin, CC BY 2.5 He-Ne laser: 2007siddharthsingh2006, CC0 Laser diode: John Maushammer, CC BY-SA 3.0 #Laser #Physics #MaterialsScience #Optics #Photonics #StimulatedEmission #Semiconductors #Science #STEM