Femtosecond pulse generation with voltage-controlled graphene saturable absorbers

Abstract

We describe experiments where voltage controlled graphene supercapacitor devices are used as saturable absorbers to initiate femtosecond pulses from tunable solid-state lasers. The device architectures allow the control of the Fermi level and hence the overall insertion loss of these devices at low operating voltages on the order of a few volts. Hence, they can be readily incorporated into the resonator of low-gain solid-state lasers. After the background sections on laser fundamentals and ultrafast pulse generation, the second part of the Chapter focuses on the spectroscopic characteristics of graphene and use of graphene supercapacitor devices as saturable absorbers to initiate femtosecond pulses. We present comparative, experimental data taken with a multi-pass cavity, Cr4+:forsterite laser, where two different graphene-based supercapacitor device architectures were used to generate sub-100-fs pulses near 1250 nm.