In short. Very short pulses shatter pigment with less heat, which suits defined targets. What that buys, what it costs in downtime and price, and what it cannot treat.

Key points

  • The two are often described as though the picosecond laser were a more powerful version of the same thing.
  • They are not the same thing at all.
  • A short pulse at one wavelength is not a substitute for a spread of wavelengths, and a broadband source is not a weaker version of a laser.

A picosecond laser delivers its energy in pulses measured in trillionths of a second. That single fact determines what it is good for. When energy arrives faster than heat can travel, pigment particles are broken apart by a mechanical effect rather than cooked by heat, and the skin around them is left comparatively undisturbed. The result is a treatment that is precise rather than broad.

What the short pulse buys

Precision has practical consequences. A defined target — a single dark spot, a cluster of freckling, pigment sitting deeper than a broadband source reaches, tattoo ink — can be treated with less heating of the surrounding skin. Less heat means less collateral change in colour, which matters most in skin that pigments easily. It also means some pigment that resists other approaches can be broken up, because the particle is shattered rather than slowly warmed. Fractional picosecond modes add a modest effect on how the surface looks and on some scars, although that is a smaller part of what the technology does than advertising suggests.

Not a stronger broadband light

The two are often described as though the picosecond laser were a more powerful version of the same thing. They are not the same thing at all. A short pulse at one wavelength is not a substitute for a spread of wavelengths, and a broadband source is not a weaker version of a laser. Where they overlap — superficial scattered pigment — both can work. Where they do not, neither substitutes for the other.

What it does not do

A picosecond laser is a narrow instrument, and the list of things outside it is long. It does not treat diffuse redness: a wavelength chosen for pigment does not target haemoglobin, and the flush across cheeks and nose is not what it is for. It does not cover a large area evenly in the way a broadband source does, so mottled sun damage spread across a face is not its natural target. It does not change skin structure, does not reposition tissue, does not remove a fold and does not restore volume. It does not diagnose anything. And it does not stop pigment from returning, with one exception: tattoo ink that has been cleared does not come back.

What it costs you

  • Purpura. With some wavelengths, especially for pigment and ink, a bruise-like change appears and takes a week or more to fade. It is expected rather than a complication, and it is visible.
  • Cost per session. The device, its maintenance and its handpieces are expensive, and a shorter course does not necessarily mean a smaller total.
  • Risk in the wrong skin. Darker skin types and recently tanned skin carry a real risk of the treated area lightening or darkening, and settings that ignore that can leave a lasting change.

Chosen for the target

A picosecond laser is the right instrument for a defined target and the wrong one for a broad pattern, and both halves of that sentence carry equal weight. It is chosen because of what is being treated, not because it is newer or costlier. A clinic that offers it for everything is describing its equipment rather than your skin.

Related reading

Frequently asked questions

What does a picosecond pulse do that a longer pulse does not?

It delivers energy faster than heat can travel away from the target. Pigment particles are therefore broken apart mechanically rather than warmed until they break down, and the skin around them is heated less. In practice that means a defined particle — a discrete spot, deeper pigment, tattoo ink — can be treated with less change to the surrounding colour, which matters most in skin that pigments easily.

Is the downtime worse than with broadband light?

It depends on the wavelength and the target rather than on the technology as a whole. Redness and mild swelling are usual. With some wavelengths used for pigment and ink, a bruise-like purpura appears and takes a week or more to clear, which is a visible downtime that broadband light does not usually produce. Where no purpura is induced, the days afterwards are broadly comparable.

Does it treat redness or rosacea?

Not the diffuse flushing across the cheeks and nose. A picosecond laser is used at wavelengths chosen for pigment, and haemoglobin is not the target at those wavelengths. Diffuse redness from small superficial vessels is treated with a broadband source or a vascular laser, not with a pigment laser. If redness is your main complaint, say so, because it changes which light is considered.

Risks & Limitations

  • Redness, warmth and swelling for hours to a few days after either light source; pigment often darkens before it flakes away over the following week.
  • Purpura — a bruise-like change — with some picosecond wavelengths, taking a week or more to clear.
  • Pigmentary change in the treated area, darker in most cases and lighter in some, particularly in darker skin types and after recent sun exposure.
  • Blistering, crusting or a burn if the settings do not match the skin, and a small risk of scarring with either light source.
  • A cold sore outbreak around the mouth after treatment in people who carry the virus.
  • Results are not permanent. Sun-related pigment and redness recur, maintenance sessions are normal, and no course makes the change permanent.
  • A lesion that has not been identified should be assessed, and in some cases sampled, before any light treatment; light does not diagnose.
  • No outcome is guaranteed, and individual response varies with the lesion, the depth it sits at and the skin type.

When to Seek Care

  • Blistering, crusting or a burn in the treated area — contact the treating team the same day.
  • Rapidly increasing redness, swelling, pain or warmth, or discharge from the treated area.
  • A fever, or a cold sore outbreak around the mouth after treatment.
  • New or changing pigmentation in the treated area that is not settling as expected.
  • A lesion anywhere on the skin that is new, changing in size, shape or colour, bleeding, itching or failing to heal — seek assessment rather than treatment.
  • Difficulty breathing, or swelling of the lips, tongue or throat — seek emergency care immediately.

References & Further Reading

  • American Academy of Dermatology Association (AAD) — patient information on laser and light-based treatment
  • British Association of Dermatologists (BAD) — guidance on laser and light therapy
  • National Institute for Health and Care Excellence (NICE, UK) — relevant guidance on skin lesions and referral
  • Cochrane Library — systematic reviews in laser and light treatment of pigmented and vascular lesions

Medically reviewed by Ke He, MD (何锞), Deputy Director & Head of Skin & Laser Aesthetics. Last reviewed: 19 September 2026.

This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.