Gold nanorod saturable absorber for passive mode-locking at 1 μm wavelength

Abstract

Gold nanorods (GNRs) were used as a saturable absorber (SA) for passive mode-locking at 1 µm wavelength. The GNR-SA film was fabricated by mixing GNRs with sodium carboxymethylcellulose. The longitudinal surface plasmon resonance absorption of GNRs was used to induce mode-locking. By using the GNR-SA film, stable passive mode-locking at 1039 nm was experimentally demonstrated in an ytterbium-doped fiber laser cavity pumped by a 980 nm laser diode. The laser produced ∼440 ps pulses with a repetition rate of 36.6 MHz and an average output power of ∼1.25 mW for a pump power of ∼82 mW.

Gold nanorod as saturable absorber for Q-switched Yb-doped fiber laser

“…In fact, it should be stressed that the position of longitudinal SPR can be conveniently tuned from the visible to the infrared region by varying the aspect ratio of GNRs, suggesting that the saturable absorption of GNRs could operate at different wavebands. However, despite the fact that the saturable absorption characteristic of GNRs has been verified at 1.06 μm [32], Q-switching operation has not yet been investigated. Considering the significance of Q-switched pulses, a question naturally arises as to whether the GNRs could be used as SAs in 1.06 μm Ybdoped fiber lasers for Q-switched pulse generation.…”

Gold Nanorods as Single and Combined Saturable Absorbers for a High-Energy <named-content content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="TeX">$Q$</tex-math></inline-formula></named-content>-Switched Nd:YAG Solid-State Laser

“…Because the third-order susceptibility of gold nanoparticles required at least a few picoseconds to rise [13], the saturation intensity of the GNRs induced by nanosecond or CW lasers should be lower than that induced by femtosecond lasers at the same excitation wavelength [14]. Furthermore, because the saturable absorption of the nanoparticles is dominated by the SPR properties, the saturation intensity of the GNRs also depends on the excitation wavelength, shapes, and sizes of the nanorods [7]- [9], [11].…”

“…The weak TSPR band is always located at the visible region, while the intense LSPR band can be flexibly tuned from the visible to the near-infrared region by changing the aspect ratio. Recently, GNRs have been successfully exploited as SAs for the generation of short pulses in Q-switched or modelocked fiber lasers [6]- [11]. As for the Q-switched Er fiber lasers, pulses at 1562 nm with a pulse width of 1.78 s and a pulse energy of 0.13 J were obtained with the microfiber-based evanescent field interaction scheme [8], while 4.8 s and 0.31 J pulses at 1560 nm were generated in the GNRs film sandwich configuration [9].…”

“…As for the Q-switched Er fiber lasers, pulses at 1562 nm with a pulse width of 1.78 s and a pulse energy of 0.13 J were obtained with the microfiber-based evanescent field interaction scheme [8], while 4.8 s and 0.31 J pulses at 1560 nm were generated in the GNRs film sandwich configuration [9]. Regarding mode-locking operation, 887 fs pulses at 1552 nm and $440 ps pulses at 1039 nm were obtained from GNRs-based modelocked Er and Yb fiber lasers, respectively [10], [11]. In comparison with the fiber lasers, bulktype solid state lasers show potential for further pulse energy scaling, because their large mode areas allow more energy to be stored.…”

van der Waals Layered Tin Selenide as Highly Nonlinear Ultrafast Saturable Absorber

“…However, they suffer from limited operating bandwidth and expensive fabrication costs, which demand the development of new cost‐effective broadband SAs, ideally with more superior performance. To this end, a variety of materials have been investigated thus far, which include carbon nanotubes, black phosphorus, gold nanoparticles and/or nanorods, filled‐skutterudites, and topological insulators (TIs) . Recently, enormous research efforts have been dedicated to 2D materials such as graphene, graphene oxide, phosphorene, and transition‐metal dichalcogenides (TMDCs), as well as MXene that was first suggested by our recent study indicating the great promise of its large material option for SA .…”