Graphene-gold supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation

We report, for the first time to our knowledge, a voltage-controlled graphene-gold supercapacitor saturable absorber, as a modulator with adjustable insertion loss for low-gain mode-locked lasers. Nearly transform-limited, 80-fs pulses were generated near 1240 nm. © OSA 2015

Graphene-gold supercapacitor as a voltage controlled saturable absorber for femtosecond pulse generation

We report, for the first time to the best of our knowledge, use of a graphene-gold supercapacitor as a voltage controlled fast saturable absorber for femtosecond pulse generation. The unique design involving only one graphene electrode lowers the insertion loss of the device, in comparison with capacitor designs with two graphene electrodes. Furthermore, use of the high-dielectric electrolyte allows reversible, adjustable control of the absorption level up to the visible region with low bias voltages of only a few volts (0-2 V). The fast saturable absorber action of the graphene-gold supercapacitor was demonstrated inside a multipass-cavity Cr:forsterite laser to generate nearly transform-limited, sub-100 fs pulses at a pulse repetition rate of 4.51 MHz at 1.24 μm. © 2016 Optical Society of America

Femtosecond pulse generation from a Ti3+: Sapphire laser near 800 nm with voltage reconfigurable graphene saturable absorbers

We experimentally show that a voltage-controlled graphene-gold supercapacitor saturable absorber (VCG-gold-SA) can be operated as a fast saturable absorber with adjustable linear absorption at wavelengths as low as 795 nm. This was made possible by the use of a novel supercapacitor architecture, consisting of a high-dielectric electrolyte sandwiched between a graphene and a gold electrode. The high-dielectric electrolyte allowed continuous, reversible adjustment of the Fermi level and, hence, the optical loss of the VCG-gold-SA up to the visible wavelengths at low bias voltages of the order of a few volts (0-2 V). The fast saturable absorber action of the VCG-gold-SA and the bias-dependent reduction of its loss were successfully demonstrated inside a femtosecond Ti3+:sapphire laser operating near 800 nm. Dispersion compensation was employed by using dispersion control mirrors and a prism pair. At a bias voltage of 1.2 V, the laser operated with improved power performance in comparison with that at zero bias, and the VCG-gold-SA initiated the generation of nearly transform-limited pulses as short as 48 fs at a pulse repetition rate of 131.7 MHz near 830 nm. To the best of our knowledge, this represents the shortest wavelength where a VCG-gold-SA has been employed as a mode locker with adjustable loss. © 2017 Optical Society of America

Femtosecond pulse generation from an extended cavity Cr4+: Forsterite laser using graphene on YAG

A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013

Graphene-gold supercapacitor as a voltage controlled saturable absorber for femtosecond pulse generation

We report, for the first time to the best of our knowledge, use of a graphene-gold supercapacitor as a voltage controlled fast saturable absorber for femtosecond pulse generation. The unique design involving only one graphene electrode lowers the insertion loss of the device, in comparison with capacitor designs with two graphene electrodes. Furthermore, use of the high-dielectric electrolyte allows reversible, adjustable control of the absorption level up to the visible region with low bias voltages of only a few volts (0-2 V). The fast saturable absorber action of the graphene-gold supercapacitor was demonstrated inside a multipass-cavity Cr:forsterite laser to generate nearly transform-limited, sub-100 fs pulses at a pulse repetition rate of 4.51 MHz at 1.24 μm

Femtosecond pulse generation with voltage-controlled graphene saturable absorbers

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Femtosecond pulse generation with voltage-controlled graphene saturable absorbers

We report, for the first time to our knowledge, the demonstration of a graphene supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation from a solid-state laser. By applying only a few volts of bias, the Fermi level of the device could be shifted to vary the insertion loss, while maintaining a sufficient level of saturable absorption to initiate mode-locked operation. The graphene supercapacitor was operated at bias voltages of 0.5–1V to generate sub-100 fs pulses at a pulse repetition rate of 4.51 MHz from a multipass-cavity Cr4+:forsterite laser operating at 1255 nm. The nonlinear optical response of the graphene supercapacitor was further investigated by using pump–probe spectroscopy

Graphene supercapacitor as a voltage controlled saturable absorber for femtosecond pulse generation

For the first time to our knowledge, we employed a graphene supercapacitor as a voltage controlled saturable absorber at bias voltages of 0.5-1V to generate 84-fs pulses from a solid-state laser near 1255 nm

Graphene mode-locked multipass-cavity femtosecond Cr⁴⁺: Forsterite laser

We report, for the first time to our knowledge, the use of graphene as a saturable absorber in an energy-scaled femtosecond Cr4+ : forsterite laser. By incorporating a multipass cavity, the repetition rate of the original short resonator was reduced to 4.51 MHz, which resulted in the generation of 100 fs, nearly transform-limited pulses at 1252 nm with a peak power of 53 kW. To the best of our knowledge, this is the highest peak power obtained from a room-temperature, femtosecond Cr4+ : forsterite laser mode locked with a graphene saturable absorber. The corresponding pulse energy was 5.3 nJ with only 24 mW of average output power. The saturation fluence and modulation depth of the GSA were measured to be 25 μJ/cm2 and 0.74%, respectively. The nonlinear effects in the Cr4+ : forsterite medium that limit further power scaling were also investigated by using different output couplers. © 2013 Optical Society of America