基于高次谐波的特性，在上海光源X光学测试线分别进行了吸收谱、成像和衍射相关检测实验，拓展了在线检测中同步辐射的光谱范围和应用场景。利用元素Se的K吸收边对光子能量为12.658 keV高次谐波进行测量，实现了Si（111）双晶单色器4.219 keV能量下限的标定；利用Si（111）晶体的光子能量12 keV高次谐波的衍射成像，研究了晶体热形变引起的Si（333）晶格面衍射的光斑畸变现象；利用双晶单色器出射的光子能量为60keV的高次谐波，完成了对Si（111）高能劳厄晶体摇摆曲线的测量。

Yb³⁺/Er³⁺ co-doped Na₅Lu₉F₃₂ single crystals used as a spectral up-converter to improve the power conversion efficiency of perovskite solar cells are prepared via an improved Bridgman approach. Green and red up-conversion (UC) emissions under the excitation of near-infrared (NIR) bands of 900–1000 nm and 1400–1600 nm can be observed. The effectiveness of the prepared materials as a spectral converter is verified by the enhancement of power conversion efficiency of perovskite solar cells. The sample with a UC layer is 15.5% more efficient in converting sunlight to electricity compared to the UC layer-free sample due to the absorption of sunlight in the NIR range. The results suggest the synthesized Yb³⁺/Er³⁺ co-doped Na₅Lu₉F₃₂ single crystals are suitable for enhancing the performance of perovskite solar cells.

A highly transparent Eu3+-doped CaGdAlO4 (CGA) single crystal is grown by the floating zone method. The segregation coefficient, x ray diffraction, and x ray rocking curve are detected, and the results reveal that the single crystal is of high quality. The f–f transitions of Eu3+ in the host lattice are discussed. The D05–F72 emission transition at 621 nm (red light) is dominant over the D05–F71 emission transitions at 591 and 599 nm (orange light), agreeing well with the random crystal environment of Eu3+ ions in a CGA crystal. The decay time of Eu:D05 is measured to be 1.02 ms. All the results show that the Eu:CGA crystal has good optical characterization and promises to be an excellent red- fluorescence material.

A Ce3+ ion-doped α-NaYF4 single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of NaF:KF:YF3:CeF3 in the molar ratio of 30∶18∶48∶4, where the KF is shown to be an effective assistant flux. The x ray diffraction, absorption spectra, excitation spectra, and emission spectra of the Ce3+-doped α-NaYF4 single crystal are measured to investigate the phase and optical properties of the single crystals. The absorption spectrum of the Ce3+:α-NaYF4 shows a strong band that peaks at the wavelength of 300 nm. The emission spectrum of the Ce3+:α-NaYF4 emits an intense ultraviolet (UV) band at the wavelength of 332 nm under the excitation of 300 nm light. Two separated luminous bands of 330 and 350 nm, which correspond to the transitions 5d→F5/22 and 5<

We report the transformation of a linear electro-optically tunable non-phase-matched second-order nonlinear process into a cascaded second-order nonlinear process in a bulk KTP crystal to generate the effect of electro-optically tunable Kerr-type nonlinearity. By applying an electric field on the x–y plane, parallel to the z-axis of the crystal, phase mismatch is created, which introduces a nonlinear phase shift between the launched and reconverted fundamental waves from the generated second harmonic wave. Due to the nonuniform radial intensity distribution of a Gaussian beam, a curvature will be introduced into the fundamental wavefront, which focuses or defocuses the incident beam while propagating through the crystal.