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Dual Sagnac loop mirror SOA-based widely tunable dual-output port fiber laser

A widely tunable (30 nm) fiber laser based on a double Sagnac loop mirror configuration is proposed and demonstrated. A semiconductor optical amplifier (SOA) placed between the two loop mirrors acts as the gain medium. The fiber laser has two output ports with adjustable optical power outputs. Wavelength tunability is obtained through the use of a thin film tunable filter, while optical power adjustability is accomplished by proper adjustment of each of the loop mirror reflectivity via a polarization controller. A total output power of + 9 dBm is measured and the potential for higher output powers is discussed. Optical power stability of better than +/- 0.15 dB is measured for 6 hours.

Nonlinear optical responses in two-dimensional transition metal dichalcogenide multilayer: WS 2 , WSe 2 , MoS 2 and Mo 0.5 W 0.5 S 2

Synthetic two-dimensional transition metal dichalcogenides such as, tungsten disulphide (WS₂), tungsten diselenide (WSe₂), molybdenum disulphide (MoS₂) as well as mixed molybdenum tungsten disulphide (Mo_0.5W_0.5S₂) single crystals were grown by the chemical vapor transport method using halogens (bromine or chlorine) as transport agents. Multi- layer samples were cleaved from the single crystals, and their nonlinear optical (NLO) properties were obtained from both open aperture and closed aperture Z-scan measurements using a picosecond mode-locked Nd: YAG laser operating at a wavelength of 1064 nm, with pulse duration of 25 ps, and 20 Hz repetition rate. Both WS₂ and MoS₂ exhibited nonlinear saturable absorption (SA), whereas WSe₂ and Mo_0.5W_0.5S₂ showed nonlinear two-photon absorption (2PA). A large 2PA coefficient β as high as + 1.91x10^-8 cm/W was obtained for the Mo_0.5W_0.5S₂, and an index of refraction coefficient γ = -2.47x10^-9 cm²/W was obtained for the WSe₂ sample.

Plasmon assisted enhanced nonlinear refraction of monodispersed silver nanoparticles and their tunability.

Nonlinear optical characterizations were performed on monodispersed silver (Ag) nanoparticles (NPs) of various sizes using a picosecond Z-scan technique with excitation wavelengths of 532 nm and 1064 nm. The Ag NPs were fabricated using a heterogeneous condensation technique in a gas medium. The nonlinear refraction values were higher for the monodispersed Ag NPs whose surface plasmon resonance (SPR) peak is closer to the excitation wavelength. The higher nonlinear optical response is explained in terms of an electric field enhancement near the SPR. Moreover, the fabrication method allows the tailoring of the nonlinear refraction index of the Ag NPs by tuning the SPR peak of the sample. A comparison of the nonlinear refraction index of the monodispersed and polydispersed Ag NPs showed that the nonlinear refractive index of the monodispersed Ag NPs is higher.

Synthesis of selenium nanoparticles and their nonlinear optical properties

Selenium nanoparticles were fabricated using a physical deposition method based on heterogeneous condensation. The Selenium nanoparticles were deposited on a quartz substrate and the ultrafast nonl...

Nonlinear optical responses in two-dimensional transition metal dichalcogenide multilayer: WS 2 , WSe 2 , MoS 2 and Mo 0.5 W 0.5 S 2 : publisher’s note

This publishers note amends the Funding section of a recent publication [Opt. Express24, 20685 (2016].