We present, to the best of our knowledge, the first demonstration of thermal, optical, and laser properties of Y b : G d S c O 3 for potentially efficient ultrashort pulse lasers. The stimulated emission cross section at 1025 nm (E//c) is 0.46 × 10 − 20 c m 2 with the emission band width of 85 nm, even broader than the well-known Y b : C a G d A l O 4 . It has quite a high thermal conductivity of 5.54 W / ( m ⋅ K ) at 50°C, comparable with Yb:YAG. In the continuous-wave regime, the maximum output power of 13.45 W at 1063.9 nm was generated with the optical-to-optical efficiency of 63.3%. These results suggest that the Y b : G d S c O 3 crystal is a promising candidate for ultrashort pulse lasers.

A novel nanofabrication technique based on double layer ultra-thin anodized aluminium oxide (AAO) membranes is demonstrated.

We report on the growth, polarized spectroscopy and first laser operation of an orthorhombic (space group Pnma) Tm³⁺,Ho³⁺-codoped gadolinium orthoscandate (GdScO₃) perovskite-type crystal. A single crystal of 3.76 at.% Tm, 0.35 at.% Ho:GdScO₃ was grown by the Czochralski method. Its polarized absorption and fluorescence properties were studied revealing a broadband emission around 2 µm. The parameters of the Tm³⁺ ↔ Ho³⁺ energy transfer was quantified, P₂₈ = 1.30 × 10⁻²² cm³µs^-1, and P₇₁ = 0.99 × 10⁻²³ cm³µs^-1, and the thermal equilibrium lifetime was measured to be 3.5 ms. The crystal-field splitting of Tm³⁺ and Ho³⁺ multiplets in C_s symmetry sites of the perovskite structure was determined by low-temperature spectroscopy and the mechanism of spectral line broadening is discussed. The continuous-wave Tm,Ho:GdScO₃ laser generated 1.16 W at ∼2.1 µm with a slope efficiency of 50.5%, a laser threshold of 184 mW, a linear laser polarization ( E || c ) and a spatially single-mode output. The Tm,Ho:GdScO₃ crystal is promising for broadly tunable and femtosecond mode-locked lasers emitting above 2 µm.

We report on the investigation of continuous-wave (CW) and SEmiconductor Saturable Absorber Mirror (SESAM) mode-locked operation of a Yb:GdScO₃ laser. Using a single-transverse-mode, fiber-coupled InGaAs laser diode at 976 nm as a pump source, the Yb:GdScO₃ laser delivers 343 mW output power at 1062 nm in the CW regime, which corresponds to a slope efficiency of 52%. Continuous tuning is possible across a wavelength range of 84 nm (1027–1111 nm). Using a commercial SESAM to initiate mode-locking and stabilize soliton-type pulse shaping, the Yb:GdScO₃ laser produces pulses as short as 42 fs at 1065.9 nm, with an average output power of 40 mW at 66.89 MHz. To the best of our knowledge, this is the first demonstration of passively mode-locking with Yb:GdScO₃ crystal.

In recent twenty years, the research on nuclear clocks based on Th nuclear transition has become increasingly intensive. Among them, solid-state nuclear clocks based on thorium-doped crystals are considered to have unique advantages in the detections of accurate energy and lifetime of nuclear isomers and the stability and miniaturization of optical clocks. In this work, The feasibility and potential of using Th:$\mathrm{BaLi}{\mathrm{F}}_3$ single crystal as a solid-state nuclear clock material was calculated and predicted by using density functional theory (DFT). The theoretical results showed that Th ions could be effectively doped in $\mathrm{BaLi}{\mathrm{F}}_3$ crystal through a suitable charge compensation mechanism, and only slightly decreased the transmittance of $\mathrm{BaLi}{\mathrm{F}}_3$ crystal in the nuclear transition band. On this basis, a Th:$\mathrm{BaLi}{\mathrm{F}}_3$ single crystal was successfully grown through experiments. Th concentration of the as-grown crystal can reach $3.13\times {10}^{18}\mathrm{c}{\mathrm{m}}^{-3}$, and the transmittance can reach $T$ ∼ 50% at ∼150 nm. Compared with the pure $\mathrm{BaLi}{\mathrm{F}}_3$ crystal grown under similar conditions, it only slightly decreased. The Th:$\mathrm{BaLi}{\mathrm{F}}_3$ single crystal is expected to be a potential candidate for solid-state nuclear clock material.