Группа авторов

Processing of Ceramics


Скачать книгу

efficiency is as low as approximately 5%.

Schematic illustrations of (a) Appearance and microstructure, (b) cw laser performance, and (c) oscillation spectrum of BMZT ceramics.

      Source: Kaminskii et al. [12]© 2009, John Wiley & Sons.

      Schematic illustration of (a) Optical transmission of 2%Yb:CaF2 transparent ceramics window in comparison with that of non-doped CaF2 single crystal. (b) Room temperature scattering coefficient of a 4 at.%-doped Yb:CaF2 ceramic. Schematic illustration of (c) the comparison between the lasing efficiency curves of a 4%-doped Yb:CaF2 ceramic and a 4.5% Yb:CaF2 single crystal versus absorbed pump power neglecting saturation effects.

      Source: Sarthou [13].© 2016, John Wiley & Sons.

      (b) Room temperature scattering coefficient of a 4 at.%‐doped Yb:CaF2 ceramic. (c) Comparison between the lasing efficiency curves of a 4%‐doped Yb:CaF2 ceramic and a 4.5% Yb:CaF2 single crystal versus absorbed pump power neglecting saturation effects.

      Source: Aballea et al. [14]© 2015, The Optical Society.

Schematic illustration of dependence of the average output power on the absorbed pump power under quasi-cw pumping.

      Source: Chen et al. [16].

Schematic illustration of the appearance of Cr-doped ZnSe, and Fe-doped ZnSe ceramics by hot press and Fe:ZnSe single crystal as reference.

      Source: Mirov et al. [17].

Schematic illustrations of absorption and fluorescence spectra of (a) Cr-doped ZnSe, ZnS, and CdSe and (b) Fe-doped ZnSe and CdMnTe.

      Source: Modified from [17].

      2.3.5 Fiber Ceramics as Laser Gain Media

      In general, glass materials have large σ (stimulated emission cross section) and τ (fluorescence lifetime) and are materials that have a large energy storage capacity and large output of laser power. However, due to their low thermal conductivity and low repetition rate of continuous‐wave and pulse oscillation, crystalline materials are industrially being applied. The above problem can be solved by adding a laser‐active element to a glass fiber having a diameter of about several tens of μm or smaller, and the laser emitted from the fiber can simplify the optical system or it can be mounted on a robot arm and so on. Hence, the technical range is different from the lasers that use bulky solid gain media. However, regarding the fiber laser, if a crystalline fiber (ceramic) can be made instead of glass fiber, the laser gain length (fiber length) of the fiber can be shortened and the heat dissipation characteristics will