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A broadband and compact TE-pass/TM-stop polarizer is presented based on hybrid plasmonic grating (HPG) on an x-cut Lithium-Niobate-on-isolator (LNOI) platform. By comprehensively analyzing the effects of metal width on mode effective index, mode similarity, and mode conversion, we demonstrate the structure with a narrow metal layer. The simulation results indicate that the polarizer with a compact length of 9 m achieves an extinction ratio over 20 dB within the wavelength range from 1470 nm to 1700 nm. The insertion loss is below 2.3 dB in C-band. Furthermore, the polarizer exhibits large fabrication tolerance to current fabrication technology.

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We report a nanosecond (ns) 165 nm deep-ultraviolet (DUV) laser with a maximum average power of 2.14 mW by eighth-harmonic generation (EHG) of a homemade ns 1319 nm Nd:YAG laser. The EHG was performed by cascaded second-harmonic generation (SHG) through successive stages of two LiB3O5 crystals and one KBe2BO3F2 crystal. The generated radiation at 165 nm is the shortest DUV wavelength ever generated through SHG method and the highest average power of all solid state lasers below 170 nm to our knowledge. Such a ns DUV laser at 165 nm is of great interest for photoemission spectroscopy and Raman spectroscopy.

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We demonstrate a ps 167.75-nm vacuum-ultraviolet (VUV) laser by cascaded second-harmonic generation (SHG). The VUV laser is produced by eighth-harmonic generation (EHG) of a mode-locked ps 1342-nm Nd:YVO4 amplifier through three stages cascaded SHG with two LiB3O5 crystals and one KBe2BO3F2 crystal, successively. The 167.75-nm laser provides up to 65-μW output power, and the corresponding photon flux and photon flux density are 5.5×10(13)  s(-1) and 1.6×10(18)  s(-1)·cm(-2), respectively.

Mid-infrared (MIR) nonlinear optical crystals of LiInSe₂ (LISe) were grown by a modified Bridgman technique on a (001)-seed. A 7-12 μm widely tunable picosecond (ps) MIR optical parametric amplifier (OPA) based on a LISe crystal was demonstrated for the first time, to the best of our knowledge. The MIR OPA was pumped by a 30 ps 1064 nm Nd:YAG laser and injected by a KTiOPO₄ (KTP)-based widely tunable near-infrared seed. The idler operating at 7.5 μm with the highest pulse energy of 170 μJ was obtained under a pump energy of 14 mJ. The corresponding energy conversion efficiency is ∼1.21%, and the photon conversion efficiency is 8.6%. The output energies were measured to be ∼121  μJ at 7 μm and ∼21  μJ at 12 μm.

In this article, we will report the low temperature Raman studies of Li 0.12 Na 0.88 NbO 3 ceramics at the ferroelectric-ferroelectric phase transitions. The spectral pattern indicates the phase transition occurs at 200 K in the cooling process and at 280 K on heating. The observed spectra are discussed as they relate to the internal stretching modes of the NbO 6 octahedron and cation translation modes. The temperature-dependent spectra show that the phase transitions may involve the rearrangement of Na ϩ cation, the relative orientation of the NbO 6 octahedral, and the displacement of Nb ions.