Optical labyrinth I

One of the last puzzles in the escape room, the optical table featured several hidden physics elements, most importantly lasers, along with a beam splitter and mirrors.  
Lasers are among the most important inventions in physics in the last fifty years. Like LEDs, they rely on quantum mechanics, but they work differently and produce higher-quality light. The name “laser” stands for “light amplification by stimulated emission of radiation”, highlighting the key difference: amplification.  

Electrons in atoms can lose energy and emit light by jumping from a higher energy level to a lower one. The color of the light is determined by the energy loss of the electrons. This process of light emission usually occurs randomly (stochastically) but can be stimulated.

By exciting electrons to higher energy levels with an external power source and then triggering them with photons of exactly the right energy, electrons emit identical photons. Using mirrors to reflect these photons back and forth multiplies them, creating an enormously powerful beam of coherent light.  

• Laser: Wikipedia 
• Image source: Science Pavilion UZH