Neodymium-doped Yttrium Vanadate-manufacture,factory,supplier from China

Research BackgroundLithium Yttrium Fluoride (LiYF4, YLF) crystal has many excellent properties such as low melting point, low phonon energy, small thermal lens effect, natural polarization, etc. It is a laser matrix material with excellent performance. YLF belongs to the tetragonal structure of scheelite, and the space group is I41/a.

1. 3 2 ~ 3 μm laser crystals doped with Cr2+ The mid-infrared luminescence of transition metal ions (Ni2+, Co2+, Cr2+, Fe2+, etc.) is based on 3d→3d transitions. According to the different types of sites occupied by transition metal ions in the host material, they can be divided into two categories: occupying octahedral sites with inversion symmetry (such as: Ni2+, Co2+ doped halides); Symmetric tetrahedral sites (such as: Ni2+, Co2+, Cr2+, Fe2+ doped II-VI compounds).

1. ~ 2 μm laser crystals doped with Tm3+ or Ho3+Tm3+ has a strong absorption near ~790 nm and a large absorption cross-section, so the ~790 nm commercial LD can be directly used as a pump source.

1. 2   ~ 2.3 μm laser crystals doped with Tm3+ Compared with the 2 μm band (3F4 → 3H6) of Tm3+, the 2.3 μm laser operation based on the 3H4 → 3H5 transition of the Tm3+ doped laser medium has the following advantages: (1) ~790 nm LD is directly pumped to the upper energy level of the laser. Tm3+ has a strong absorption around 790 nm (directly corresponding to the 3H4 → 3H6 transition), which can match the emission wavelength of the current mature commercial AlGaAs LD, so as to realize high-performance LD pumping all-solid-state high-efficiency 2.3 μm laser operation.

1.5  ~ 4 μm laser crystals doped with Fe2+ Compared with Cr:ZnSe, Fe:ZnSe has a smaller band gap and is prone to produce thermally induced multi-phonon quenching, so both laser power and efficiency are low. In 1999, Adams et al. realized the tunable wavelength of 3.98-4.54 μm at low temperature for the first time in Fe:ZnSe, and obtained laser output with slope efficiency of 8.2%. Pumped by Er3+ doped or Cr:ZnSe @ 2.7 μm laser, 4.0 μm wavelength and 1 W level continuous laser output have been obtained at room temperature. In 2020, Pushkin et al.

1. 4  ~ 3 μm laser crystals doped with Er2+, U4+, Ho3+, Dy3+  As an active ion, Ho3+ has achieved laser output in the ~3 μm band (5I6→5I7). In 1976, researchers first realized 2.9 μm laser output in Ho:YAP crystal. In 1990, Bowman et al. obtained 2.85 μm and 2.92 μm laser outputs in Ho:YAP crystals, and obtained 2.92 μm band-tuned laser outputs in Ho:YAP crystals in the following year. In 2017, Nie et al. pumped Ho, Pr: LiLuF4 crystals with a 1 150 nm Raman fiber laser, achieving 2.95 μm watt-level laser output for the first time. In 2018, Zhang et al.

Nanoscale laser damage precursorsDifferent from microscopic defects, defects are called precursors here. Defects generally refer to observable microstructures that are different from the characteristics of the surrounding matrix materials, and are often observed by optical microscopy. The precursors mentioned in this article generally cannot be directly observed by optical methods, and there is no obvious difference in characteristics from the surrounding matrix materials.

Laser damage induced by microscopic defects in optical componentsAccording to the above numerical analysis results, it can be seen that cracks may be generated around the nodule seed and propagate along the radial direction.

2.1 Manipulating and understanding laser damage precursors through material growth processesCombined with the statistical model, information such as precursor density and threshold distribution can be extracted from the damage probability curve, which indirectly reflects the information of the precursor. The analysis shows that the KDP crystal (www.wisoptic.com) mainly contains a precursor with a threshold distribution.

1. Research status and future development trend of mid-infrared (2-5 μm) laser crystalsAccording to the order of laser wavelength from short to long, the main material that have achieved laser output (including some optical fibers and transparent ceramics for comparison) are listed in Table 1. Among them, the highest continuous laser output power of laser crystals corresponding to different wave bands is shown in Figure 2. The laser output power of activated ions shows an obvious attenuation trend as the wavelength expands to the mid-infrared direction.