What are Picosecond lasers?
Picosecond lasers are devices that utilise very short pulse durations to target pigmentation. They can be 755 nm ( alexandrite) or 1064/532 nm (Nd:YAG).
They can be employed to treat a range of conditions such as melasma, Naevus of Ota, Lentigo, Cafe Au lait spots and tattoo removal.
How do they differ from Nanosecond lasers?
Utilising picosecond pulses which are 1000x shorter than a nanosecond, result in a predominantly photo-acoustic effect (pressure waves) rather than photothermal effect (heat waves) on the target structures. This allows for effective clearance of abnormal pigmentation whilst minimising thermal injury to surrounding tissues and possible side effects like post procedure discomfort, post inflammatory hyperpigmentation and depigmentation ( hypopigmentation).
In short, with Picosecond lasers, lower fluences (energy) can be used for efficient pigment destruction and with less surrounding /collateral damage to healthy skin.
What can they do differently?
Picosecond lasers were first approved for tattoo removal and being able to treat tattoos in less sessions and with shorter downtimes compared to regular Q-switched nanosecond lasers. The small size of tattoo particles require very short pulses of laser energy (shorter than the thermal relaxation time of the target) to effectively target and break them up. Picosecond lasers with high peak power and short pulse duration are therefore best suited for this purpose.
Laser induced optical breakdown or LIOB for short is a phenomenon unique to picoseond lasers. The high energy and pressure generated by the laser is deployed to create micro-bubbles in the dermis and sometimes epidermis layers of the skin. After treatment, there is remodeling of the tissues with increase in both elastin and collagen fibres! Thus allowing picosecond lasers to be used selectively for acne scar treatments and for skin rejuvenation in general.
Why do I still use nanosecond lasers?
- Nanosecond NdYag laser can be combined with Picosecond lasers for patients with stubborn pigmentation or refractory pigmentation problems.
- Certain treatments such as carbon peel cannot be performed with pico-second lasers! A number of my patients suffer from acne and have been treated well with a simple carbon peel, which is why I continue to provide this efficient and cost effective treatment.