Nd: YVO4 crystal laser characteristics and comparison with Nd: YAG

Pure (undoped) YVO4 crystal is an excellent birefringent optical crystal newly developed in recent years. It has good light transmission in a wide range of visible and near-infrared, with a large refractive index and birefringence. Poor rate. Compared with other important birefringent crystals, YVO4 crystals are harder than icelandite (CaCO3 single crystal), have better mechanical processing properties, are insoluble in water, and can be grown artificially (icelandite depends on natural resources); YVO4 crystals are also It is easier to grow large high-quality crystals than rutile (TiO2 single crystal), and the price is much lower than rutile. These excellent characteristics make YVO4 crystal quickly become a new type of birefringent optical material, which is widely used in the optoelectronic industry. In optical fiber communication equipment, a large number of various light splitting and polarization components made of pure YVO4 crystals, such as optical isolators, circulators, optical beam splitters, and Glan series polarizers, are required. The combination of YVO4 crystals and rutile crystals can also obtain an ideal temperature compensation effect, which greatly improves the temperature stability of the optical communication system. Neodymium-doped yttrium vanadate (Nd: YVO4) 　　 neodymium-doped yttrium vanadate (Nd: YVO4) crystal is a laser crystal with excellent performance, suitable for the manufacture of laser diode pumps, especially low- and medium-power lasers. Compared with Nd: YAG, Nd: YVO4 has a higher absorption coefficient and a larger stimulated emission cross section for pump light. Laser diode-pumped Nd: YVO4 crystals are used in conjunction with crystals with high nonlinear coefficients such as LBO, BBO, KTP, etc., to achieve better frequency multiplication conversion efficiency, and can be made into output types such as near-infrared, green, blue to ultraviolet rays Of all solid-state lasers. Now the Nd: YVO4 laser has been widely used in many fields such as machinery, material processing, spectroscopy, wafer inspection, display, medical inspection, laser printing, data storage and so on. Moreover, Nd: YVO4 diode-pumped solid-state lasers are rapidly replacing the traditional water-cooled ion laser and lamp-pumped laser market, especially in terms of miniaturization and single longitudinal mode output. The advantage of Nd:YVO4 compared with Nd:YAG is that the pump bandwidth around 808nm is about 5 times that of Nd:YAG. The stimulated emission cross section at 1064nm is 3 times that of Nd: YAG. The low optical damage threshold, high slope efficiency biaxial crystal, the output is linearly polarized Nd: YVO4 laser characteristics 1. Compared with Nd: YAG, Nd: YVO4 is larger The advantage lies in the wider absorption bandwidth range, the absorption efficiency is 5 times higher than that of Nd:YAG, and the peak absorption wavelength is reached around 808nm, which can fully meet the current standards of high-power laser diodes. This allows us to use smaller crystals to make smaller and smaller lasers. At the same time, it also means that the laser diode can output specific energy with a smaller power, thereby extending its service life. The absorption bandwidth of Nd:YVO4 can reach 2.4-6.3 times that of Nd:YAG. This feature also has great development value. In addition to higher pumping efficiency, it provides more room for choice in diode specifications, which will save laser manufacturers more manufacturing costs.　　 2. Nd: YVO4 has larger stimulated emission cross sections at 1064nm and 1342nm. In the a-axis direction, the stimulated emission cross section of Nd:YVO41064nm wave is about 4 times that of Nd:YAG, while the stimulated emission cross section of 1342nm can reach 18 times that of Nd:YAG at 1.3um, so the continuous output of Nd:YVO41342nm wave The efficiency is much higher than that of Nd:YAG, which makes it easier to maintain a strong single-line excitation for both wavelengths of the Nd:YVO4 laser. 3. Another important feature of Nd: YVO4 is that it belongs to a uniaxial crystal system and only emits linearly polarized light, so it can avoid birefringence interference during frequency doubling conversion. Nd: YAG is a square crystal with high uniformity. This feature. Although the fluorescence lifetime of Nd:YVO4 is about 2.7 times shorter than that of Nd:YAG, because Nd:YVO4 has a higher pump quantum efficiency, a fairly high slope efficiency can still be obtained in an ideally designed optical cavity. (The above is edited by laser cutting machine on the Internet. Please indicate the source for reprinting)