Q-switched Mode-locked Waveguide Lasers Research Articles

A Novel Hierarchical Nanostructure for Enhanced Optical Nonlinearity Based on Scattering Mechanism.

Surface modification of nonlinear optical materials (NOMs) is widely applied to fabricate diverse photonic devices, such as frequency combs, modulators, and all-optical switches. In this work, a double-layer nanostructure with heterogeneous nanoparticles (NPs) is proposed to achieve enhanced third-order optical nonlinearity of NOMs. The mechanism of modified optical nonlinearity is elucidated to be the scattering-induced energy transfer between adjacent NPs layers. Based on the LiNbO3 platform, as a typical example, double layers of embedded Cu and Ag NPs are synthesized by sequential ion implantation, demonstrating twofold magnitude of near-infrared enhancement factor and modulation depth in comparison with a single layer of Cu NPs. With the elastic collision model and thermolysis theory being considered, the shift of the localized surface plasmon resonance (LSPR) peak reveals the formation mechanism of the double-layer nanostructure. Utilizing the enhanced optical nonlinearity of LiNbO3 as modulators, a Q-switched mode-locked waveguide laser at 1µm is achieved with shorter pulse duration. It suggests potential applications to improve the performance of nonlinear photonic devices by using double-layer metallic nanostructures.

Q-switched mode-locked Nd:GGG waveguide laser with tin disulfide as saturable absorber

We demonstrate a Q-switched mode-locked waveguide laser operation with high fundamental repetition rate based on the few-layer tin disulfide (SnS2) as a saturable absorber. The excellent nonlinear optical property of SnS2 enables efficient pulsed laser generation. By using Nd:GGG ridge waveguide, the fundamental repetition rate up to 17.9 GHz has been achieved for the mode-locked pulses with duration as short as 30 ps. In addition, this Nd:GGG-based waveguide laser exhibits excellent lasing properties (maximum output power of 115 mW at 1064 nm) by modulation of SnS2, suggesting promising application as miniature ultrafast light sources.

Monolithic waveguide laser mode-locked by embedded Ag nanoparticles operating at 1 μm

Abstract Monolithic waveguide laser devices are required to achieve on-chip lasing. In this work, a new design of a monolithic device with embedded Ag nanoparticles (NPs) plus the Nd:YAG ridge waveguide has been proposed and implemented. By using Ag+ ion implantation, the embedded Ag NPs are synthesized on the near-surface region of the Nd:YAG crystal, resulting in the significant enhancement of the optical nonlinearity of Nd:YAG and offering saturable absorption properties of the crystal at a wide wavelength band. The subsequent processing of the O5+ ion implantation and diamond saw dicing of crystal finally leads to the fabrication of monolithic waveguide with embedded Ag NPs. Under an optical pump, the Q-switched mode-locked waveguide lasers operating at 1 μm is realized with the pulse duration of 29.5 ps and fundamental repetition rate of 10.53 GHz, owing to the modulation of Ag NPs through evanescent field interaction with waveguide modes. This work introduces a new approach in the application of monolithic ultrafast laser devices by using embedded metallic NPs.

WSe2 as a saturable absorber for multi-gigahertz Q-switched mode-locked waveguide lasers [Invited

Graphene and other extraordinary two-dimensional materials together with recent advances in optical modulators have set the foundations for the widespread applications of next-generation optoelectronic devices. In this work, we report on the high-performance fundamentally mode-locked waveguide laser modulated by chemical-vapor-deposition-grown WSe2 as a saturable absorber. By incorporating a WSe2 sample into a monolithic Nd:YVO4 waveguide platform, 6.526 GHz picosecond pulsed laser generation has been achieved at the wavelength of 1 μm with pulse duration of 47 ps.

Enhanced nonlinear optical response of graphene by silver-based nanoparticle modification for pulsed lasing

In this work, we report on the synthesis and characterization of a functionalized graphene modified by Ag based nanoparticles (Ag2S@Ag) and the applications as an optical modulator for pulsed laser generation at 1μm in the compact waveguide platform written by a femtosecond laser. The nonlinear optical response of the Ag2S@Ag nanoparticle modified graphene has been explored by the Z-scan technique, which exhibits an enhanced ultrafast saturable absorption response with higher modulation depth and lower saturation intensity. The Q-switching and Q-switched mode locking have been realized in a waveguide laser system by using Ag nanoparticle modified graphene as a saturable absorber (SA) mirror. Fundamental Q-switched mode-locked waveguide lasers with a repetition rate of 6.44 GHz have been achieved, reaching shorter pulse duration (33 ps) in comparison to that (52 ps) through unmodified graphene SA. This work suggests potential applications of functionalized graphene in ultrafast photonics.

65 GHz Q-switched mode-locked waveguide lasers based on two-dimensional materials as saturable absorbers

Two-dimensional (2D) materials have generated great interest in the past few years opening up a new dimension in the development of optoelectronics and photonics. In this paper, we demonstrate 6.5 GHz fundamentally Q-switched mode-locked lasers with high performances in the femtosecond laser-written waveguide platform by applying graphene, MoS2 and Bi2Se3 as saturable absorbers (SAs). The minimum mode-locked pulse duration was measured to be as short as 26 ps in the case of Bi2Se3 SA. The maximum slope efficiency reached 53% in the case of MoS2 SA. This is the first demonstration of Q-switched mode-locked waveguide lasers based on MoS2 and Bi2Se3 in the waveguide platform. These high-performance Q-switched mode-locked waveguide lasers based on 2D materials pave the way for practical applications of compact ultrafast photonics.