Ion-implanted InGaAs single quantum well semiconductor saturable absorber mirrors for passive mode-locking

We demonstrate that ion implantation can be used for response time tailoring to create high-performance indium gallium arsenide (InGaAs) quantum well semiconductor saturable absorber mirrors (SESAMs). The design and manufacture of the SESAMs are described, and their nonlinear optical and temporal responses, relevant to the mode-locking of picosecond type pulses, are given. The implanted devices shown here have response times as short as 11 ps, compared with several hundred picoseconds without implantation. They have small non-bleachable losses and low saturation fluence (≤20 μJ cm^-2), allowing for operation far below the damage threshold. An implantation- and annealing-induced quantum well intermixing effect is shown to be present in the SESAMs, resulting in an energy shift in the excitonic feature. This effect can be taken into account in the SESAM design or minimized, if necessary. Using the SESAMs to mode-lock a low-power Nd:YVO₄ laser at 1064 nm, we have generated pulsewid ths between 9 and 23 ps, depending on the cavity configuration and the SESAM used.