Systems and methods for controlling therapeutic laser pulse duration

A system for treating the skin of a patient with a therapeutic laser pulse, the system comprising:

• a) a handpiece adapted to be held by a user to cool a first skin area of the patient and to apply a therapeutic laser pulse to at least a first target skin area within the first skin area, the handpiece comprising:
• 1) a contact cooling element having a cooling window comprising a thermally conductive material that is transmissive to infrared energy and therapeutic laser light, wherein the cooling window is adapted to be placed in contact with the first skin area of the patient to cool the at least a first target skin area within the first skin area from a first surface temperature to a second surface temperature;
• b) a diode laser source coupled to the handpiece and adapted to generate and apply a single therapeutic laser pulse to each of the at least a first target skin area through the cooling window;
• c) a temperature sensor for determining a surface temperature of the at least a first target skin area a plurality of times during the application of the single therapeutic laser pulse;
• d) one or more controllers adapted to control:
• 1) the cooling of the first skin area by the contact cooling element;
• and
• 2) initiating application of a single therapeutic laser pulse to a selected target skin area of the at least a first target skin area through the cooling window at a first timepoint;
• 3) determining the surface temperature of the selected target skin area a plurality of times during the application of the single therapeutic laser pulse, based on infrared energy radiated from the selected target skin area through the cooling window, at a temperature sampling time interval of 100 msec or less;
• and
• 4) terminating the application of the single therapeutic laser pulse to the selected target skin area at a second timepoint based at least in part on the plurality of surface temperature determinations, wherein the single therapeutic laser pulse comprises a pulse duration from the first timepoint to the second timepoint.