Continuous-Wave vs Pulsed Lasers

Continuous-wave and pulsed describe how a laser delivers optical power over time. A continuous-wave laser supplies a substantially steady beam while enabled; a pulsed laser concentrates output into separated bursts. Neither term identifies the wavelength, motion system, or material by itself.

What continuous-wave means

A continuous-wave, or CW, source maintains laser emission instead of intentionally storing energy for distinct short pulses. The controller may still turn the beam on and off, vary commanded power, or modulate it rapidly, but during each enabled interval the source behaves approximately as a steady emitter.

CW processing is governed mainly by average optical power, absorption, spot size, travel speed, dwell time, focus, and heat flow. Energy continues entering the material while the spot remains illuminated, so melting, sustained heating, cutting, welding, and broad thermal modification are natural uses.

What pulsed means

A pulsed source releases optical energy in discrete bursts separated by lower-output intervals. Important quantities include pulse duration, pulse energy, pulse frequency, peak power, pulse shape, and duty cycle in addition to average power.

Concentrating energy into a short pulse can create peak power far above the source's average power. That can cross an ablation or modification threshold quickly, remove a thin region, or create a fine mark before heat conducts as far into surrounding material. Repeated pulses can still accumulate heat when overlap or pulse frequency is high.

The same average power can behave differently

A 20 W average CW beam delivers energy steadily. A 20 W average pulsed source may deliver very high instantaneous power during each pulse and little between pulses. The same average-power label therefore does not imply the same peak intensity, penetration, surface response, or safety behavior.

Pulse energy is approximately average power divided by pulse frequency when output is stable, and peak power is approximately pulse energy divided by pulse duration for a simple pulse shape. Real sources have operating maps and shaped pulses, so manufacturer data takes precedence over these estimates.

Which sources commonly use CW

Industrial cutting and welding fiber lasers are commonly CW or quasi-continuous because sustained energy supports melt formation and penetration. Many CO2 cutting and engraving lasers operate CW with controller modulation. Common desktop diode engravers also behave as CW sources whose electrical drive is modulated to command average power.

Most consumer, hobby, and small-shop galvo fiber marking lasers are primarily pulsed sources, commonly Q-switched or marking-oriented MOPA designs. Some fiber products provide a documented CW mode, a quasi-continuous-wave mode, or both, but that capability belongs to the design and control interface of the specific source; it should not be assumed from the word fiber or MOPA.

Selecting an extremely short or long Q-pulse value on an ordinary pulsed marker does not by itself turn the source into a true continuous-wave laser. A longer permitted pulse can lower peak intensity and make the material interaction more thermally CW-like, while a purpose-built QCW source uses much longer pulses and remains physically distinct from CW. If a manufacturer supports genuine CW output, use the mode, duty-cycle limits, and commands defined in that source's manual rather than inventing a pulse-width setting.

These are common patterns, not universal rules. Fiber, CO2, and UV sources can all be engineered for pulsed output, and a controller's PWM or power modulation should not automatically be interpreted as nanosecond optical pulse duration.

Which sources commonly use pulses

Q-switched fiber markers are inherently pulsed: energy builds while cavity loss is high and is released after the Q-switch opens. Many UV marking lasers are also pulsed, while marking-oriented MOPA fiber sources create seed pulses and amplify them, often providing selectable nanosecond pulse duration.

Many industrial UV markers are pulsed Q-switched, picosecond, or femtosecond sources because high peak intensity and controlled energy deposition support fine ablation. UV itself only describes wavelength; continuous-wave UV sources also exist. Pulsed CO2 and diode sources likewise exist for specialized applications.

What CW is good for

CW is a strong choice when the process benefits from sustained heat and high average energy: cutting, welding, brazing, cladding, heat treatment, deep penetration, and many CO2 engraving processes. It can provide smooth, continuous interaction while the beam moves.

CW can also deliver high throughput when material must be melted or vaporized continuously rather than modified one microscopic event at a time.

What CW is not ideal for

CW is often a poor choice when the goal requires very high peak intensity with minimal total heat, sharply confined ablation, delicate thin-film removal, fine micromachining, or precise control of individual surface-modification events. Sustained heating can enlarge the heat-affected zone, melt edges, char organics, distort thin parts, or damage nearby features.

Fast motion and short modulation can reduce thermal exposure, but modulation does not necessarily reproduce the interaction of a purpose-built nanosecond or ultrafast source.

What pulsed lasers are good for

Pulsed sources are strong for marking, engraving, drilling, cleaning, coating removal, fine ablation, texture, dark and light contrast, and micromachining. Adjustable nanosecond pulses can expand oxide-color and surface-structure experiments on suitable metals.

Picosecond and femtosecond pulses can confine energy even more strongly in time, often reducing melting and heat-affected material for precision work. Shorter is not always better; removal rate, cost, focus, debris, and material response still matter.

What pulsed lasers are not ideal for

Pulsed marking sources are often inefficient choices for thick-section cutting, deep welding, or processes that need a stable molten pool and sustained penetration. High peak power can remove surface material without delivering the continuous heat required for bulk joining or fast thick cutting.

Poorly chosen pulse energy and overlap can also produce roughness, recast, plasma shielding, spatter, or excessive heat accumulation. Very short-pulse systems add cost and complexity and may offer little benefit for ordinary cutting or broad thermal engraving.

How this appears in LightBurn

LightBurn exposes only controls supported by the selected device and controller. A MOPA device may expose pulse width; a Q-switched marker may expose frequency without independent pulse duration; a diode or CO2 controller may expose power modulation or a frequency-like setting with different physical meaning.

Do not transfer a numeric frequency or pulse-width recipe between unlike sources. Confirm what each field commands on the exact device, stay within manufacturer limits, and validate the machine, lens, focus, material, and process with small tests.

Manufacturer links

These official sites are starting points for current specifications, regional availability, demonstrations, and support. Inclusion is not an endorsement or a guarantee of compatibility.