Output optical energy pulses including relatively high energy magnitudes and steep slope at the beginning of each pulse are disclosed. As a result of the relatively high energy magnitudes which lead each pulse, the leading edge of each pulse includes a relatively steep slope. This slope is preferably greater than or equal to 5. Additionally, the full-width half-max value of the output optical energy distributions are between 0.025 and 250 microseconds and, more preferably, are about 50-70 microseconds. A flashlamp is used to drive the laser system, and a current is used to drive the flashlamp. A flashlamp current generating circuit includes a solid core inductor which has an inductance of about 50 microhenries and a capacitor which has a capacitance of about 50 microfarads. The output optical energy pulses cut target surfaces by interacting with fluid that is located above, on and/or in the target surface. Methods are disclosed for therapeutically treating tissue with pulses of electromagnetic energy.