When light starts to lase.
What turns ordinary light into laser light?
Loading the experiment…
What turns ordinary light into laser light?
Fit the gain medium, pump and both mirrors.
Pumping prepares an excited gain medium. Stimulated emission can then add light matching an existing optical field. Mirrors feed that field through the gain medium repeatedly. Lasing begins only when a round trip gains more intensity than the mirrors and medium lose. A partly transmitting mirror lets some of the resonator light become useful output.
Illustrative steady-state threshold model: cavity length 0.2 m, high mirror reflectivity 0.995, gain 0.4 max(Ppump−3,0)m⁻¹. Transparency at 3 W and output efficiency 0.25 are teaching constants, not a real laser specification. No detailed population rate equations, multimode behavior or safety simulation.
Produce at least 0.2 W of laser output above threshold.
Overcome cavity losses to produce laser output.