What Does Q-Switched Mean?
Q-switched means the laser controls the quality factor, or Q, of its resonant cavity so energy can build in the gain medium and then be released as a short, intense pulse.
What the switch controls
A laser cavity lets light circulate between mirrors and grow through stimulated emission. A Q-switch first makes the cavity deliberately lossy, suppressing a strong laser field while pumping stores energy as population inversion in the gain medium. The switch then changes the cavity to a low-loss, high-Q state.
When that path opens, stored energy is released rapidly as a pulse with much higher peak power than continuous output at the same average power. The switch may be acousto-optic, electro-optic, or passive depending on the design.
What happens at the material
A pulse can heat, melt, vaporize, ablate, or chemically and structurally modify the focused region. The balance depends on pulse energy, duration, wavelength, spot size, absorption, and how pulses overlap while scanning.
The material begins cooling between pulses, but high pulse frequencies and close spatial overlap can accumulate heat. Q-switched marking is not necessarily a sequence of isolated cold events.
Why frequency changes pulse behavior
At a lower pulse frequency, the gain medium often has more time to store energy before the next release, producing greater pulse energy and peak power. At a higher pulse frequency, pulses arrive more often but may contain less energy because recharge time is shorter.
The exact relationship is source-specific. On many conventional Q-switched markers, pulse duration, shape, energy, and peak power vary with frequency rather than being independently selectable.
Q-switched versus MOPA
A conventional Q-switched fiber marker is effective for identification, engraving, texture, cleaning, coating removal, and many dark or light marks. Its pulse behavior is commonly tied more tightly to pulse frequency.
A MOPA source separates pulse generation and amplification, commonly providing a wider selectable pulse-duration range and more freedom to explore peak power and heat delivery.
Practical controls
Speed sets how far the beam travels between pulses; frequency controls timing; power changes output; hatch interval and angle arrange scan lines; focus and lens set spot and field; passes repeat the process. Because pulse width may not be exposed, useful control comes from supported frequency, speed, power, and overlap combinations.
Record the exact source, controller, lens, focus, and material. A MOPA recipe cannot be converted to a Q-switched recipe simply by omitting pulse width.
For current examples spanning pulsed fiber configurations, compare Cloudray's fiber marking machines. Confirm the exact source architecture rather than relying on the category name.