Graphene saturable absorber mirror for ultra-fast-pulse solid-state laser

Abstract

High-quality graphene sheets with lateral size over 20 μm have been obtained by bath sonicating after subjecting the wormlike graphite marginally to mixed oxidizer. To date, to our knowledge, they are the largest graphene sheets prepared by exfoliation in the liquid phase. A saturable absorber mirror was fabricated based on these sheets. We exploited it to realize mode-locking operation in a diode-pumped Nd:GdVO(4) laser. A pulse duration of 16 ps was produced with an average power of 360 mW and a highest pulse energy of 8.4 nJ for a graphene mode-locked laser.

Optical Third-Harmonic Generation in Graphene

“…Because ideal freestanding monolayer graphene is centrosymmetric, its second-order nonlinear response vanishes within the dipole approximation [24]. In contrast, symmetry-allowed third-order nonlinear optical effects in graphene are remarkably strong, leading to studies that include saturable absorption [27][28][29][30][31][32], optical limiting [33,34], two-photon absorption [35], four-wave mixing (FWM) [36,37], and current-induced SHG [38]. In one notable FWM investigation, the authors have estimated the third-order nonlinear susceptibility of single-layer and multilayer graphene and demonstrated the capability of FWM for imaging of graphene using two input beams [36].…”

Watt-level Q-switched Nd:LuVO4laser based on a graphene oxide saturable absorber

“…where T and T 0 stand for the transmission of the graphene oxide saturable absorber and the initial transmission of the quartz substrate and α is the absorption of the monolayer graphene oxide, which is estimated at 2.3% [13]. The measured transmission of the graphene oxide at 1064 nm was between 79.6% and 83%.…”

Mode-locked 2-μm wavelength fiber laser using a graphene-saturable absorber

“…2 Since then, mode-locked lasers have been created using graphene as a saturable absorber at wavelengths in the near IR. [3][4][5][6][7][8][9][10] Theory predicts graphene's performance as a saturable absorber at wavelengths beyond 1.55 μm. 9 Graphene's broadband performance has been shown by a few groups by using it as a saturable absorber to modelock lasers at wavelengths longer than 1.55 μm.…”

“…Graphenebased SAMs have been fabricated via (1) dispersion of graphene in a solution with poly(methyl methacrylate) 20 and polyvinyl-alcohol, 21 (2) liquid-phase exfoliation of small area (∼20 μm) flakes, 8,22,23 or (3) chemical vapor deposition on copper foils and transferral to a mirror. 3,10 Until now, epitaxially grown graphene on silicon carbide (SiC) was used as a saturable absorber only in Q-switched lasers, 9,19,24,25 and not in mode-locked lasers.…”

“…This is a tremendous advantage for creating continuous graphene layers over large areas that are unachievable with the popular method of sonication of graphite. 8,22,23 In addition, using graphene synthesized on SiC opens up a potential avenue for mass production of saturable absorber feedstock. Such an approach will benefit from the obvious economies of scale associated with the commercial business of GaN on SiC LEDs as well as the increasingly important low voltage (600 V) SiC current switches that are of interest for applications such as in the auto industry.…”