Waveplate

Holmium-doped Yttrium Aluminum Garnet (Ho:YAG) is an important solid-state laser crystal. Due to the excellent physicochemical properties of theYAG matrix, it can withstand high thermal loads and is an important pumpsource laser crystal for mid-wave infrared lasers. At the same time, it is alsoan ideal light source for coherent Doppler wind radar, differentialabsorption radar, and laser rangefinders.

HGO grows Ho:YLF laser crystals using Czochralski technology. Ho:YLF is a very attractive laser material, because the lifetime of the upper laser level is much longer ( ~ 14 ms) than in Ho:YAG and the emission cross sections are higher. Additionally the thermal lens in Ho:YLF is much weaker, which helps to generate diffraction limited beams even under intense end-pumping. The primary advantage of directly pumping the Ho 5I7 is that it does not have to depend on energy transfer, which lends itself to various radiative and non-radiative losses. Up-conversion losses that have deleterious effect in high-energy Q-switched lasers are eliminated.

The Anamorphic prisms are used in pairs to magnify input beam size along one axis while leaving the other axis unchanged. The elliptical laser diode beams can be transferred into nearly circular.

Cr4+:YAG (Y3Al5O12) crystal is ideal for passive Q-switch operation of Nd:YAG and other Nd3+ or Yb3+ doped laser crystals in the wavelength range of 900 nm to 1200 nm. Passive Q-switches or saturable absorbers provide high power laser pulses without electro-optic Q-switches, thereby reducing the package size and eliminating a high voltage power supply. A remarkable feature of Cr4+:YAG is the high damage threshold of >10 J/cm2@1064 nm, 10 ns. Its absorption band extends from 900 nm to 1200 nm and peaks around 1060 nm with a very large absorption cross-section.

Germanium (Ge) is the preferred lens and window material for high performance infrared imaging systems in the 8–12 um wavelength band.

Laser mirrors are fabricated with specialized coatings, which will offer high damage thresholds.

Plano-concave rectangular cylindrical lenses provide uni- axial negative imaging for anamorphic beam expansion and a wide range of applications.These lenses may also be used as mirror blanks if a concave cylindrical surface mirror is required.

Ytterbium-doped Potassium Gadolinium Tungstate (Yb:KGd(WO₄)₂, Yb:KGW) crystal is an excellent laser gain material, boasting numerous advantages over the widely used Nd³⁺-doped materials. Its wide spectral emission band of 1023-1060 nm enables the generation of short laser pulses (picosecond or femtosecond level). The broad absorption band at 980 nm and highly absorbent pump radiation allow it to efficiently utilize diode laser pumping. Compared with YAG doped with Yb³⁺ ions, KGW crystal has a larger absorption cross-section, which reduces the minimum pump intensity required to achieve transparency in the quasi-two-level system of Yb.