###### Abstract
They used crystals with a Ti\({}^{3+}\)-ion doping concentration of 0.1 wt.%, but the FOM available at this concentration is generally less than approximately 400 [16; 17; 18; 19; 20; 21; 22; 23; 24; 25] and, of course, low-loss crystals with such FOM must be specially ordered [16]. The highest efficiencies among fiber-laser-based SHG laser-pumped CW Ti:sapphire lasers were achieved by [PERSON] et al. in 2012 [11]. Using Ti:sapphire crystals with a FOM of 270 or higher, which may be easily commercially available, they achieved an optical-to-optical conversion efficiency of approximately 24% and a slope efficiency of 32.9%. In 2018, we obtained an optical-to-optical conversion efficiency of 31.7% and slope efficiency of 41.2% at a low pump power of 3.5 W [12; 13]. These efficiencies were obtained by high-intensity pumping using commercially available crystals. To our knowledge, the optical-to-optical conversion efficiency of 31.7% is the highest in experiments using commercially available crystals up to that time. For the first time since either 28.1% in 1991 or approximately 24% in 2012, the optical-to-optical conversion efficiency of CW Ti:sapphire lasers using commercially available crystals has been updated. In addition, for the first time since 1994, the new, highest slope efficiency has been updated despite \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Author (Year)** & \begin{tabular}{c} **Pump** \\ **Wavelength (nm)** \\ \end{tabular} & **Pulse Width** & **FOM** & \
\begin{tabular}{c} **Incident Pump** \\ **Power (W)** \\ \end{tabular} &
\begin{tabular}{c} **Optical-to-Optical** \\ **Conversion** \\ **efficiency \(\eta_{\text{m}}\) (\%)** \\ \end{tabular} & **Slope Efficiency \(\eta_{\text{m}}\) (\%)** \\ \hline [PERSON] et al. (1982) [1] & - & 500 ns & - & - & - & - \\ [PERSON] et al. (1991) [6] & 488/514 & 60 fs & - & 8 & 5.63 & - \\ [PERSON] et al. (2008) [7] & 532 & 4.4 fs & - & 5.5 & 1.64 & - \\ [PERSON] et al. (1994) [8] & - & - & & 2.2 & - \\ [PERSON] et al. (1991) [9] & 488/514 & CW & - & -7.5 & 28.1 & 32.0 \\ [PERSON] et al. (1994) [10] & 488/514 & CW & 1000 & -10 & 35 & 40 \\ [PERSON] et al. (2012) [11] & 532 & CW & \textgreater{}270 & -11 & -24 & 32.8 \\ [PERSON] et al. (2018) [12; 13] & 532 & CW & 200 & 3.5 & 31.7 & 41.2 \\ [PERSON] et al. (2021) [14] & 532 & CW & \textgreater{}250 & 22.5 & \textgreater{}40 (seeeding & 51 (pump power \textgreater{}11 W, with seeding) \\ Spectra-Physics 3900 5 & & & & power included) & with seeding) \\ (commercial, 2022 [15] & 532 & CW & - & -10 & \textless{}22 & - \\ This work (2022) & 532 & CW & 200 & 5.0 & 32.4 & 42.5 \\ \hline \end{tabular}
\end{table} 
Table 1: Comparison of Ti:sapphire lasers. These efficiencies are for the incident pump power to the gain medium. the use of commercially available crystals. In 2021, the efficiencies of Ti:sapphire lasers with injection seeding and high pump power were updated by [PERSON] et al. [14]. Using high pump powers of more than 20 W, high optical-to-optical conversion efficiencies of approximately 40% or higher (seeding power included) were obtained. The slope efficiency was also as high as 51% in the high pump power range of over 11 W. As of 2022, the highest optical-to-optical conversion efficiency of commercially available CW Ti:sapphire lasers is around 22% or less [15]. Thus, here, we propose a method to increase the efficiencies of Ti:sapphire lasers, in which all components are commercially available, by high-intensity pumping. First, we report an experiment on a high-efficiency CW Ti:sapphire laser using commercially available crystals with high-intensity pumping. In this experiment, the obtained optical-to-optical conversion efficiency is 32.4% and the slope efficiency is 42.5%. Furthermore, we have succeeded in confirming the reliability of our theoretical analysis by theoretically reproducing the experimental results.