We demonstrate single-mode microdisk lasers in the telecom band with ultralow thresholds on erbium-ytterbium co-doped thin-film lithium niobate (TFLN). The active microdisk was fabricated with high-Q factors by photolithography-assisted chemomechanical etching. Thanks to the erbium-ytterbium co-doping providing high optical gain, the ultralow loss nanostructuring, and the excitation of high-Q coherent polygon modes, which suppresses multimode lasing and allows high spatial mode overlap between pump and lasing modes, single-mode laser emission operating at 1530 nm wavelength was observed with an ultralow threshold, under a 980-nm-band optical pump. The threshold was measured as low as 1 µW, which is one order of magnitude smaller than the best results previously reported in single-mode active TFLN microlasers. The conversion efficiency reaches 4.06 × 10^-3, which is also the highest value reported in single-mode active TFLN microlasers.

We demonstrate integrated lithium niobate (LN) microring resonators with Q factors close to the intrinsic material absorption limit of LN. The microrings are fabricated on pristine LN thin-film wafers thinned from LN bulk via chemo-mechanical etching without ion slicing and ion etching. A record-high Q factor up to 108 at the wavelength of 1550 nm is achieved because of the ultra-smooth interface of the microrings and the absence of ion-induced lattice damage, indicating an ultra-low waveguide propagation loss of ∼0.0034dB/cm. The ultra-high Q microrings will pave the way for integrated quantum light source, frequency comb generation, and nonlinear optical processes.

We report an electro-optically (EO) tunable microdisk laser fabricated on the erbium (Er3+)-doped lithium niobate on insulator (LNOI) substrate. By applying a variable voltage on a pair of integrated chromium (Cr) microelectrodes fabricated near the LNOI microdisk, electro-optic modulation with an effective resonance-frequency tuning rate of 2.6 GHz/100 V has been achieved. This gives rise to a tuning range of 45 pm when the electric voltage is varied between -200V and 200 V.

We demonstrate high-quality (intrinsic Q factor ∼2.8 × 10⁶) racetrack microresonators fabricated on lithium niobate thin film with a free spectral range (FSR) of ∼86 pm. By integrating microelectrodes alongside the two straight arms of the racetrack resonator, the resonance wavelength around 1550 nm can be red shifted by 92 pm when the electric voltage is raised from -100 V to 100 V. The microresonators with the tuning range spanning over a full FSR are fabricated using photolithography assisted chemo-mechanical etching.

当前微纳尺度的三维金属结构，由于其独特的物化性能和空间构型优势，在科学与工程领域的应用需求日益增多。由此应运而生的各种三维金属微尺度打印技术近年来相继被开发，并引起了广泛关注。在众多技术中，基于激光的三维微打印技术有着非接触加工、制造灵活性好等优势。文中综述了当前一些代表性的激光辅助三维金属微打印技术，总结了各种三维金属微打印的基本原理、技术优势及典型应用。针对高表面光滑度、高熔点、高电导率的三维金属微打印存在的挑战，介绍了超快激光制备玻璃微通道模具法辅助实现三维金属微制造的新技术。最后就三维金属微打印的未来方向和应用前景进行了探讨。