- Nd:YAG and Ruby are examples of solid-state laser systems
- A flashlamp is used to excite (or “pump”) the gain medium in these lasers
- Cr3+ ions in ruby undergo transitions to produce lasing in a Ruby laser
- Nd3+ ions in a yttrium aluminum garnet (YAG) matrix are the optically active species in a Nd:YAG laser
- Transitions in ruby occur mainly between three levels, whereas Nd:YAG is referred to as a 4-level system (see the energy level diagram, below).
- The fundamental lasing transitions are at 694 nm and 1064 nm for Ruby and Nd:YAG lasers, respectively.
Four-level energy diagram. Simplified diagram showing transitions for Nd3+ in a Nd:YAG laser.