Pulses on Demand in Fibre and Hybrid Lasers

Abstract

This paper presents an investigation of pulse-on-demand operation in fibre and hybrid lasers. Two methods for efficient gain control that enable the generation of laser pulses at arbitrary times with controlled pulse parameters are presented. The method of direct modulation of the pump power in the high-power laser oscillator is shown to generate pulses with a duration in the nanosecond range, with repetition rates varying during operation from a single shot to over 1 MHz. An advanced method using a combination of marker and idler seeding a fibre amplifier chain is investigated. Such a system can easily achieve repetition rates of several tens of MHz. The lasers’ performances were successfully tested in a real environment on an industrial platform for laser transfer printing. Similar concepts were used for a laser source with ultrashort laser pulses (femtosecond range) on demand by using a mode-locked seed as a source and a solid-state amplifier to achieve high pulse energy and peak power.

Regenerative Shaper of Ultrashort Light Pulses

“…The optimal repetition rate depends on the imaging depth, so a tunable repetition rate source has to be used to ensure optimal operation at different penetration depths [5]. Similarly, in laser processing of materials using polygon scanners, the laser-light source needs to operate at a variable repetition rate in order to create arbitrarily arranged structures [6].…”

Pulse-on-demand laser operation from nanosecond to femtosecond pulses and its application for high-speed processing

“…Similar issue arises with resonant scanners, where the speed of the laser beam on the workpiece sinusoidally changes due to the sinusoidal oscillation of the scanner mirror. Lasers that are compatible with both polygon and resonant scanners, that is that they are capable of generating arbitrary patterns on the workpiece, must therefore be able to generate laser pulses on demand [6].…”