Publications by authors named "Dunlu Sun"

Article Synopsis
  • The study explores how thermal bonding and concave end faces impact the performance of 795 nm laser diodes (LD) when used to pump Tm:YAP crystals.
  • Concave end faces help to counteract thermal lensing effects, allowing for higher power output, reaching 42.5 W with a slope efficiency of 47.4% and optical-optical conversion efficiency of 41.6%.
  • Compared to flat bonding rods, the concave design improves the maximum output power and efficiencies, demonstrating its effectiveness in enhancing heat dissipation and laser performance.
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We report on a polarization-resolved study of mid-infrared emission properties of Er-doped orthorhombic yttrium aluminum perovskite YAlO single crystal. For the I→ I Er transition, the stimulated emission cross section is 0.20 × 10cm at 2919 nm for light polarization E ‖ c.

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We demonstrated a 978 nm laser diode (LD) side-pumped YSGG/Er:YSGG/YSGG composite crystal with a size of Ф 3 mm × 65 mm and continuous-wave (CW) mode. By optimizing resonator length and output mirror transmittance, a maximum output power of 28.02 W is generated, corresponding to slope efficiency of 17.

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We demonstrate the thermal, spectroscopy and laser properties of Ho,Pr doped YAP crystal grown successfully by Cz method. The thermal expansion coefficient, thermal conductivity, absorption and emission spectra of Ho,Pr:YAP crystal are investigated in detail. Additionally, the level lifetimes suggest that Pr is a suitable deactivating ion for Ho:YAP crystal.

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In this work, we report on investigations of structure, spectroscopic properties and laser performances of, what we believe to be, a novel Er:YGGAG laser crystal. High crystalline quality is proved by an FWHW of XRC of 0.019°.

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We demonstrate a 968-nm LD side-pumped Er:YAP laser with concave end-faces and a working frequency of 50∼1000 Hz. The maximum average powers of 26.75 and 13.

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We demonstrate a novel Er:LuSGG active gain medium emitting laser wavelength at 2795 nm for the first time. The Er:LuSGG crystal is grown successfully by the Czochralski method with high crystalline and optical quality. The spectra properties, including absorption and fluorescence emission cross-section are presented in contrast with similar Er-doped garnet crystals.

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We demonstrate a laser diode (LD) end-pumped Er:YAP laser with dual-wavelength outputs of 2710 and 2728 nm. The maximum average powers of 739 and 738 mW are achieved in the continuous wave (CW) and pulse modes, which corresponds to optical-to-optical efficiencies of 10.1% and 12.

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We demonstrate a 966 nm laser diode (LD) side-pumped Er,Pr:GYSGG laser crystal operated at 2.79 μm under a high repetition rate. The lifetimes of the upper level I4 and lower level I4 are 0.

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The surface laser damage performance of fused silica optics is related to the distribution of surface defects. In this study, we used chemical etching assisted by ultrasound and magnetorheological finishing to modify defect distribution in a fused silica surface, resulting in fused silica samples with different laser damage performance. Non-destructive test methods such as UV laser-induced fluorescence imaging and photo-thermal deflection were used to characterize the surface defects that contribute to the absorption of UV laser radiation.

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We demonstrate the thermal analysis and laser performance of a GYSGG/Cr,Er,Pr:GYSGG composite crystal. The lifetime ratio of lower and upper levels of Er in Cr,Er,Pr:GYSGG crystal is further reduced due to the optimized doping concentrations. The thermal effect of composite crystal is lower than that of Cr,Er,Pr:GYSGG crystal.

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We report passively Q-switched ∼2 and ∼3  μm mid-infrared (MIR) solid-state lasers with a self-assembly solvothermal-synthesized BiTe/graphene heterostructure saturable absorber (SA) for the first time. Based on the oxidation resistance and high thermal conductivity of graphene, and large modulation depth of BiTe nanosheets, two high-performance Q-switching lasers were realized. One is a Tm:YAP laser with a maximum average output power of 2.

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We demonstrate the growth, spectroscopy, and laser performance of a 2.79 μm Cr,Er,Pr:GYSGG radiation-resistant crystal. The lifetimes for the upper laser level (4)I(11/2) and lower laser level (4)I(13/2) are 0.

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Passively Q-switched mode-locking performance of Nd:GdTaO crystal using molybdenum disulfide (MoS) as a saturable absorber at 1066 nm was demonstrated for the first time. The MoS saturable absorber was prepared simply by transferring the MoS suspension onto a quartz substrate. By inserting the MoS saturable absorber into the Nd:GdTaO laser, stable Q-switched modelocked operation can be achieved.

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We demonstrate a comparative investigation on Er,Pr:GYSGG and GYSGG/Er,Pr:GYSGG composite crystals at 2.79 μm. Simulating results show the highest temperatures are 369 K and 318 K, respectively.

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We demonstrate a 968 nm diode end-pumped Er,Pr:GYSGG (Gd₁.₁₇Y₁.₈₃Sc₂Ga₃O₁₂) laser at 2.

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A flash lamp pumped Cr,Er:YSGG laser utilizing a langasite (LGS) crystal as an electro-optic Q-switch is proposed and demonstrated. It is proved that a LGS crystal with relatively high damage threshold can be used as the electro-optic Q-switch at 2.79 μm, and 216 mJ pulse energy with 14.

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We demonstrate a dual-wavelength laser based on a new laser material-Nd, Gd:YSGG, or Nd:GYSGG for short-for the first time to our knowledge. Besides its attractive properties such as antiradiation, high segregation coefficient, etc., this kind of laser crystal also shows excellent laser performance.

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In the present paper, the authors measured the Raman spectra of YAG/Nd : YAG single crystal, Nd : YAG precursor and the powder sintered at different temperatures. The bands of these Raman spectra were assigned and analyzed. The results show that there is a structure transformation process in the course of sintering Nd : YAG precursor.

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A highly doped Er3+: LiNbO3 (concentration 6 mol%) crystal was grown successfully by Czochralski method. The crystal is higher than that of the lowly doped Er3+ in LiNbO3 crystal, which is helpful to improve absorption coefficient of the grown the pumping efficiency. The absorption spectra at two unpolarized directions (X and Z) and two polarized directions (E parallel Z, E perpendicular Z) were measured.

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In this article, a good-quality crystal Yb:YAG was grown by pull method, and its absorption spectrum of 200-3000 nm was measured at room temperature. Its absorption of 200-300 nm is from the host YAG, and there exists only the characteristic absorption of Yb3+ in the range of 390-3000 nm. Judd-Ofelt theory computation indicates that the absorption and emission oscillator strengths of electric dipole of (24 at%) Yb:YAG are 3.

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