# Progress in Transparent Nano-Ceramics and Their Potential Applications
## 2 Transparent Nano-Ceramics for Solid-State LASERs
### Application  
The schematic diagram of YAG transparent nano-ceramics' application in a laser diode pumping system is shown in Figure 4. As depicted in Figure 4, a symmetrical ring pump source was created using 32 groups of laser diodes (the highest output of an LD at 807 nm was 10 W) and a \(\phi\)4 mm \(\times\) 105 mm 0.6% Nd:YAG transparent nano-ceramic rod. Then, a high-power Nd:YAG ceramic laser with CW 1.46 kW was developed [13], and this was the first time that the output power of a ceramic laser exceeded the kilowatt level. The experimental findings showed that increasing the pump power to 290 W resulted in an 88 W multimode CW laser output. This meant that the light-to-light efficiency of YAG transparent nano ceramics was about 30%. In 2010, Marsh Corporation in the United States used multiple Nd:YAG transparent ceramic slabs with composite structures to achieve a laser output of more than 100 kW using direct pumping technology, of which the output power of a single Nd:YAG slab could reach 17 kW [33;34]. [PERSON] [31] developed a high-power efficient transparent ceramic Yb:YAG laser with a Yb concentration of 9.8%, a pumping power of 13.8 W, a T = 10% output coupler, and a cavity length of 20 mm at a room temperature of 20 \({}^{\circ}\)C. At a maximum output power of 1.6 W, the ceramic Yb:YAG laser showed continuous tunability in the spectral region of 63.5 nm from 1020.1 to 1083.6 nm. A high-power passive Q-switched Ho:YAG ceramic laser was created by [PERSON] et al. [35]. The maximum pulse energy of this laser was 0.94 mJ, the pulse width was 28 ns, and the peak power was 33.5 kW at a pulse-repetition frequency of 28.8 kHz. \begin{table}
\begin{tabular}{l l l l} \hline
**Doping Type** & **Year, Powder, and Fabrication** & **Findings** & **Performance** & **Remarks** \\ \hline Nd\({}^{3+}\)-doped & & The average grain size and relative density of the 1.1 at. \(\%\) Nd:YAG ceramics were about 50 \(\mu\)m and 99.98\(\%\), respectively. & For the first time, polycrystalline ceramics were successfully used for effective laser cutting. \\ \hline
2002; raw nano powder of oxide and aluminum, yttrium, and & In laser experiment of Nd:YAG ceramics and single-crystal rods, the Nd:YAG materials the light-to-light efficiency of Nd:YAG nanocrystalline ceramics were obtained, respectively [13]. & Compared with single-crystal \\  & & In laser experiment of Nd:YAG ceramics and single-crystal rods, the Nd:YAG materials the light-to-light efficiency of Nd:YAG nanocrystalline ceramics were obtained, respectively [13]. & Nd:YAG materials the light-to-light efficiency of Nd:YAG nanocrystalline ceramics needs to be further improved. \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of doped YAG transparent nano-ceramics described in the text grouped by doped type and published year. \begin{table}
\begin{tabular}{c c c c c} \hline
**Doping Type** & **Year, Powder, and Fabrication** & **Findings** & **Performance** & **Remarks** \\ \hline
2010. an average particle size of 100 nm by reverse-stike & & The infrared transmittance of the sample was 80\%, and its emission spectrum was the same as 14.\% & Nd: YAG nano powder with an average size of about 100 nm was prepared for the first time. \\ precipitation method; HIP method. & & NdYAG single crystal [14]. & prepared for the first time. \\ \end{tabular}
\end{table} 
Table 1: _Cont._ \begin{table}
\begin{tabular}{c c c c c} \hline
**Doping Type** & **Year, Powder, and Fabrication** & **Findings** & **Performance** & **Remarks** \\ \hline \hline Ho-doped & 2015, the nano powders were made up of near-spherical particles; solid-state reaction involving a pre-calcining stage. & & The slope efficiency of laser oscillations in the fabricated Ho-YAG transparent ceramic sample for pumping power was 40\% (at 1.85 \(\mu\)m) [21]. & Based on the nano-powders prepared by laser ablation, Ho-YAG optical ceramics with finer particle size were prepared. \\ Ho-doped & & & \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._