Nonlinear optical responses in two-dimensional transition metal dichalcogenide multilayer: WS2, WSe2, MoS2 and Mo0.5W0.5S2: publisher's note.

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

Nonlinear optical responses in two-dimensional transition metal dichalcogenide multilayer: WS2, WSe2, MoS2 and Mo 0.5 W0.5 S2.

Synthetic two-dimensional transition metal dichalcogenides such as, tungsten disulphide (WS2), tungsten diselenide (WSe2), molybdenum disulphide (MoS2) as well as mixed molybdenum tungsten disulphide (Mo0.5W0.5S2) 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 Mo0.5W0.5S2 showed nonlinear two-photon absorption (2PA). A large 2PA coefficient ß as high as + 1.91x10-8 cm/W was obtained for the Mo0.5W0.5S2, and an index of refraction coefficient γ = -2.47x10-9 cm2/W was obtained for the WSe2 sample.

Switchable dual-wavelength SOA-based fiber laser with continuous tunability over the C-band at room-temperature.

We propose and demonstrate a simple compact, inexpensive, SOA-based, dual-wavelength tunable fiber laser, that can potentially be used for photoconductive mixing and generation of waves in the microwave and THz regions. A C-band semiconductor optical amplifier (SOA) is placed inside a linear cavity with two Sagnac loop mirrors at its either ends, which act as both reflectors and output ports. The selectivity of dual wavelengths and the tunability of the wavelength difference (Δλ) between them is accomplished by placing a narrow bandwidth (e.g., 0.3 nm) tunable thin film-based filter and a fiber Bragg grating (with bandwidth 0.28 nm) inside the loop mirror that operates as the output port. A total output power of + 6.9 dBm for the two wavelengths is measured and the potential for higher output powers is discussed. Optical power and wavelength stability are measured at 0.33 dB and 0.014 nm, respectively.

Tunable multi-wavelength SOA based linear cavity dual-output port fiber laser using Lyot-Sagnac loop mirror.

We propose and demonstrate a simple dual port tunable from the C- to the L-band multi-wavelength fiber laser based on a SOA designed for C-band operation and fiber loop mirrors. The laser incorporates a polarization maintaining fiber in one of the fiber loop mirrors and delivers multi-wavelength operation at 9 laser lines with a wavelength separation of ~2.8 nm at room temperature. We show that the number of lasing wavelengths increases with the increase of the bias current of the SOA. Wavelength tunability from the C to L-band is achieved by exploiting the gain compression of a SOA. Stable multi-wavelength operation is achieved at room temperature without temperature compensation techniques, with measured power and the wavelength stability within < ±0.5 dB and ±0.1 nm, respectively.

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.

Sign of chi((3)) in polysilane polymers.

The signs of the third-order optical nonlinear susceptibility chi((3)) of polysilane have been determined to be negative at 532 nm and positive at 1064 nm from single-beam Z-scan measurements. The small and positive chi((3)) at 1064 nm arises from the bound-electronic process. The negative chi((3)) at 532 nm is attributed to two-photon absorption resonance transition.

Implementation of a binary optical full adder using a Venn diagram and optical phase conjugation.

Conventional optical pattern logic schemes can only process two input variables at a time. We propose a new optical spatial encoding scheme that is capable of simultaneously processing multiple input variables. Based on this new scheme an optical full adder was experimentally demonstrated using a picosecond optical phase-conjugation device.

Nonlinear-optical response in polythiophene films using four-wave mixing techniques.

We report measurement of X(3) in polythiophene and a homologous series of polycondensed thiophene-based polymers above and below the absorption edge using the folded-boxcar four-wave mixing technique. Above gap the nonlinear coefficient X(3) was found to be one of the largest and fastest in a polymer.

Real-time measurements of phonon lifetime using a streak-camera-Raman-induced phase-conjugation method.

A novel real-time technique to measure phonon dynamics using the Raman-induced phase-conjugation method in combination with streak-camera technology is described. The technique is used to determine vibrational and optical phonon dephasing kinetics of CS(2), calcite, and LiNbO(3) with a temporal resolution of 3 psec.

Picosecond Raman-induced phase conjugation in liquids and solids.

We have used the new Raman-induced phase conjugate (RIPC) technique to obtain strong Raman signals using picosecond laser pulses. We have obtained the picosecond RIPC spectra of carbon disulfide, benzene, nitrobenzene, and calcite. By delaying one of the interacting pump beams relative to the other pump and probe beams we were able to determine the intensities of the phase conjugate beams at the Stokes frequencies as a function of time with 20-ps resolution. These measurements show the potential of this technique to determine phonon relaxation times in condensed matter using shorter laser pulses.