Vertical-Cavity Surface-Emitting Lasers (VCSELs) are very attractive to high power light sources owing to the
advantageous configuration of two-dimensional arrays and being free from catastrophic optical damage. Although oxideconfined
VCSELs have been employed in most of applications with VCSELs, ion-implanted VCSELs have a potential to
be the better light sources for high power applications. In spite of the fact, the detailed characteristics of the ionimplanted
VCSELs had been researched only in ten milliwatt-class output power. Here we report on a high power
VCSEL-array with proton-implanted current apertures. A peak output power of over 40 W under short-pulse operation
has been achieved. This is the first demonstration of ten watt-class output power for ion-implanted VCSELs.
We have developed a 389-nm frequency-doubled nanosecond-pulsed coherent light source with injection seeding for nuclear polarization of <sup>3</sup>He atoms with 2<sup>3</sup>S→3<sup>3</sup>P and then suggested four kinds of spectroscopic methods with the injection-seeded light source. With this light source, we have conducted saturated absorption spectroscopy of metastable <sup>3</sup>He atoms. As a result, an accurate resonance frequency of 770682 GHz and a dip width of 1.7 GHz of metastable <sup>3</sup>He atoms are obtained. Therefore, the linewidth of our injection-seeded light source can be estimated at 65 MHz or 1.7 GHz. Our light source has potential for the polarization of <sup>3</sup>He due to high-peak power and narrow linewidth of the injection-seeded light source.
We investigate optical properties of semiconductor atoms by absorption and
emission spectroscopies. Each of <sup>3</sup>P<sub>J'</sub> - <sup>3</sup>P°<sub>J</sub> transitions except for J'=0 (the total angular
momentum of the ground state) is confirmed in broad emission spectra in a hollow-cathode
discharge in which negative electrodes incorporate semiconductor atoms that are evaporated
in the discharge. For finer spectroscopies, the <sup>3</sup>P<sub>1</sub> - <sup>3</sup>P°<sub>0</sub> cyclic transition for laser cooling of
silicon atoms at 252 nm is investigated in absorption spectra with a single-frequency tunable
deep-UV coherent light source, which has a high potential for controlling their nuclear spins.