Chuandong Sun

Bio: Chuandong Sun is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Laser & Fiber laser. The author has an hindex of 7, co-authored 14 publications receiving 133 citations.

Design and optimization of highly nonlinear low-dispersion crystal fiber with high birefringence for four-wave mixing

Abstract: We have proposed a novel type of photonic crystal fiber (PCF) with low dispersion and high nonlinearity for four-wave mixing. This type of fiber is composed of a solid silica core and a cladding with a squeezed hexagonal lattice elliptical airhole along the fiber length. Its dispersion and nonlinearity coefficient are investigated simultaneously by using the full vectorial finite element method. Numerical results show that the proposed highly nonlinear low-dispersion fiber has a total dispersion as low as ±2.5 ps nm−1 km−1 over an ultrabroad wavelength range from 1.43 to 1.8 μm, and the corresponding nonlinearity coefficient and birefringence are about 150 W−1 km−1 and 2.5×10−3 at 1.55 μm, respectively. The proposed PCF with low ultraflattened dispersion, high nonlinearity, and high birefringence can have important application in four-wave mixing.

Growth, spectroscopic characteristics and laser potential of Yb 3+ :Ca 3 La 2 (BO 3 ) 4 crystal

Abstract: Crystal of Yb3+-doped Ca3La2(BO3)4 has been grown by the Czochralski technique. The room temperature absorption and fluorescence spectra of the crystal have been investigated. The result showed that this crystal exhibits broad absorption and emission with the FWHM of 11 nm at 978 nm and 66 nm FWHM at 1025 nm, respectively. The stimulated emission cross-section of Yb3+ ions were calculated using the reciprocity method and Fuchtbauer-Ladenburg method, respectively. The room temperature fluorescence decay curves of 2 F 5/2 manifold of Yb3+ ions were recorded for both crystal and powder samples. The effect of radiation tapping on the spectroscopic properties is discussed. The result that the lifetime of the powder sample is shorter than that of the bulk sample demonstrates the existence of radiation trapping effect. The laser potentiality was also evaluated and the results show that this crystal is a good candidate for tunable and ultrashort pulse lasers.

All-optical switching application of germano-silicate optical fiber incorporated with Ag nanocrystals

Abstract: Ag-nanocrystal-incorporated germano-silicate optical fiber with high resonant nonlinearity was fabricated by using modified chemical vapor deposition and solution doping techniques. An all-optical signal switching application based on cross-phase modulation was demonstrated in the cascaded long-period fiber gratings. Pumped with 499 nm argon laser, all-optical signal gating of the pi-phase shift was achieved with low pump intensities of less than 7.64 GW/cm2.

End-Pumped Tm,Ho:NaY(WO4)2 Crystal Laser at 2.07 μm

Abstract: We presented an infrared laser output at 2.07 μm with Tm,Ho:NaY(WO4)2 crystal end-pumped by 795 nm laser diode at room temperature. The crystal was grown by the Czochralski method with the concentrations of 5 at % Tm3+ and 1 at % Ho3+. The highest output power was up to 2.7 W corresponding to the crystal temperature being controlled at 283 K. The overall optical conversion efficiency was 5.4% and the slop efficiency was 26%. The output characteristics and the laser threshold affected by the pulse duration and temperature have been studied. We found the stability of the output power was correlative with the crystal temperature heavily. In addition, the wider pulse duration of pump could promote the output power efficiently.

Excessively tilted fiber grating based Fe3O4 saturable absorber for passively mode-locked fiber laser.

Abstract: A novel approach to saturable absorber (SA) formation is presented by taking advantage of the mode coupling property of excessively tilted fiber grating (Ex-TFG). Stable mode-locked operation can be conveniently achieved based on the interaction between Ex-TFG coupled light and deposited ferroferric-oxide (Fe3O4) nanoparticles. The central wavelength, bandwidth and single pulse duration of the output are 1595 nm, 4.05 nm, and 912 fs, respectively. The fiber laser exhibits good long-term stability with signal-to-noise ratio (SNR) of 67 dB. For the first time, to the best of our knowledge, Ex-TFG based Fe3O4 SA for mode-locked fiber laser is demonstrated.

Self-assembled 3D flower-shaped NaY(WO4)2:Eu3+ microarchitectures: Microwave-assisted hydrothermal synthesis, growth mechanism and luminescent properties

Abstract: Three dimensional (3D) flower-shaped microarchitectures of NaY(WO4)2 were synthesized via a microwave-assisted hydrothermal process in the presence of trisodium citrate (Na3Cit) and a post-calcination process. The effects of reaction conditions on the morphology of precursor microstructures were studied. It was found that Na3Cit, as the chelating agent and shape modifier, plays a key role in the microstructure growth. A possible growth mechanism for the flower-shaped microarchitectures was proposed. The as-formed precursor can completely transform into NaY(WO4)2 with its original flower-shaped morphology via a heat treatment process. The concentration and temperature quenching behaviors of Eu3+ fluorescence in the flower-shaped NaY(WO4)2 were studied, and the optimal doping concentration was confirmed, meanwhile the activation energy was obtained. Judd-Ofelt parameters Ωλ (λ = 2, 4 and 6) of Eu3+ in the flower-shaped NaY(WO4)2 phosphor were obtained by using the emission spectrum of Eu3+, moreover the radiative transition properties were analyzed.

Fabrication and characterization of a water-free mid-infrared fluorotellurite glass.

Abstract: Using a physical and chemical dehydration technique and a high-pressure, ultradry O2 atmosphere in a semiclosed steel-chamber furnace, we fabricated a group of fluorotellurite glasses with a composition of (90−x)TeO2-xZnF2-10Na2O (mol.%, x=0–30). For x=30, no OH absorption was observed in the range of 0.38–6.1 μm. This is the first report of a water-free mid-IR fluorotellurite glass, to our knowledge, offering the common advantages of a robust oxide glass and an IR-transparent fluoride one. Besides optimized linear transmittance and absorption, the nonlinear refractive indices and Raman gain coefficients are reduced. These results are discussed in the context of mid-IR high-power laser generation and transmission.

High-order optical nonlinearities in plasmonic nanocomposites—a review

Abstract: Composites consisting of metal nanoparticles (NPs) embedded in dielectric media may present large nonlinear optical response due to electronic transitions in the NPs. When the metal NPs are suspended in liquids or embedded in solid substrates, the obtained composites may present high-order optical nonlinearities (HON) beyond the third-order nonlinearity, usually studied for most materials. Moreover, it is observed that the magnitude and phase of the effective high-order susceptibilities can be controlled by adjusting the light intensity, I, and the volume filling fraction, f, occupied by the NPs. Therefore, the sensitivity to the values of I and f allowed the development of a nonlinearity management procedure for investigation and control of various phenomena, such as self- and cross-phase modulation, spatial modulation instability, as well as bright and vortex solitons stabilization, in media presenting relevant third-, fifth-, and seventh-order susceptibilities. As a consequence, it is reviewed in this paper how the exploitation of HON in metal–dielectric nanocomposites may reveal new ways for optimization of all-optical switching devices, light-by-light guiding, as well as the control of solitons propagation for long distances. Also, theoretical proposals and experimental works by several authors are reviewed that may open the possibility to identify new high-order phenomena by applying the nonlinearity management procedure. Therefore, the paper is focused on the properties of metal nanocomposites and demonstrates that these plasmonic composites are versatile platforms for high-order nonlinear optical studies.

Diode-pumped continuous wave and passively Q-switched Tm,Ho:LLF laser at 2 µm

Abstract: A compact diode-pumped continuous wave and passively Q-switched Tm,Ho:LuLiF(4) laser is demonstrated. The maximal output power of 381 mW at 2069 nm in continuous wave regime is obtained at an absorbed pump power of 1.5 W. By using a Cr(2+):ZnS saturable absorber, the maximum Q-switched average output power of 74 mW is obtained at 2055 nm. The pulse width and pulse energy are almost independent of the absorbed pump power, with the maximal values of 1.2 μs and of 13 μJ respectively. The pulse repetition frequency can be tuned almost linearly from 1 to 5.8 kHz by changing the absorbed pump power. Furthermore, a comparative analysis of laser performances with different output couplers is first carried out.