Thulium doped YLF-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.

1.5  ~ 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. 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. 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.

3.3 Laser pretreatment of dielectric film with large diameter Laser pretreatment technology is the last process before the supply of large-diameter components with dielectric film in NIF devices in the United States. LLNL provides their laser pretreatment device and specifications to each of their supplier of thin film components.

Conclusion Considering comprehensive factors such as wide absorption bandwidth, large absorption cross section, long upper energy level lifetime (ms to tens of ms) (see Table 2), ion cross relaxation, increased quantum efficiency, and mature LD pump source, Tm3+ in the 2 μm band, Ho3+ and Er3+ in the 3 μm band must be one of the most important and basic laser sources in the mid-infrared band from 2 to 20 μm, and will compete with Nd3+ and Yb3+ in the 1 μm band.

2-5 μm mid-infrared laser crystals have important applications in directional infrared countermeasures, anti-terrorism, biomedicine, environmental monitoring, optical communications, strong field physics, laser fusion, and mid-to-far infrared (nonlinear frequency conversion) basic light sources, etc. With the related development of the pump source technology of semiconductor laser (laser diode, LD), solid-state laser and fiber laser (including resonant pump), mid-infrared crystal has become one of the four main laser crystals developed currently.

04 Theoretical study of thermal properties As can be seen from Figure 5 (a), when the BBO crystal (www.wisoptic.com) matching temperature is 60 ℃, as the 266 nm deep ultraviolet laser power gradually increases from 0.32 W to 1.24 W, 2.09 W and 2.25 W, the fitted nonlinear absorption coefficient βNLA also increases continuously, from 0 to 0.079, 0.128, and 0.189 cm/GW, respectively.