The yellow laser with a wavelength of 589 nm can be used in optogenetics, sodium laser pointer beacon, temperature and wind lidar, laser Raman, dynamic nuclear polarization, urban landscape, scientific research, national defense and military fields. It is an inevitable requirement for high-end applications to obtain yellow lasers with high efficiency, high beam quality, high stability, and narrow linewidth.
Among the most commonly used laser crystals, Nd:YAG, Nd3+ ion has two strong laser emission lines of 1064 nm and 1319 nm, and through the nonlinear sum frequency scheme, the yellow laser output of 589 nm can be easily obtained.
Single cavity dual wavelength sum frequency 589 nm laser
The end-pumped structure is adopted, and the laser cavity contains two laser crystals. The laser crystal on the left side of the purple in Figure 1 is a 1319 nm laser crystal, with 1319 nm and 808 nm double antireflection coatings on both sides. The laser crystal on the right side of the purple in Figure 1 is a 1064 nm laser crystal, one side is coated with 1319 nm and 808 nm antireflection coatings, and a 1064 nm high-reflection coating.
The other side is coated with 1319 nm, 1064 nm and 808 nm antireflection coatings. The 1064 nm resonant cavity is embedded in the 1319 nm resonant cavity to achieve coaxial green laser pointer output. Through the special design of the resonant cavity, a smaller beam waist is realized at the position of the nonlinear crystal, and the peak power density acting on the nonlinear sum frequency crystal is increased. The etalon group is further inserted into the resonant cavity to narrow the line width. At the same time, it can achieve the best power matching of 1064 nm and 1319 nm to achieve high-efficiency output of 589 nm yellow light.
The laser product using this cavity design has the characteristics of small size, good beam quality, and high conversion efficiency. It can achieve continuous single-frequency and low-noise output. The maximum power can achieve 500 mW and the beam quality M2 is better than 1.2.