Crystals and optics processing services

HGO grows LiF crystals in house using Czochralski technology. LiF crystal or lithium fluoride crystal is an optical material with outstanding transmittance in VUV region. It is also used for windows, prisms, and lenses in the visible and infrared in 0.104µm-7µm. LiF single crystal is sensitive to thermal shock and would be attacked by atmospheric moisture at 400°C. When working at a high temperature of 600°C, the LiF crystal softens and is slightly plastic, so it can be bent into radius plates. In addition irradiation produces color centers. Hence, users should take measures to protect LiF crystals from moisture and high energy radiation damages. What is more LiF can be cleaved along (100) plane and less commonly (110) plane. The optical characteristics are good and yet the structure is not perfect and cleavage is difficult.

Nd:GdVO4, is a promising material for diode pumped lasers. Similar to the more well-known Nd:YVO4 crystal, Nd:GdVO4 crystal also exhibits high gain, low threshold, and high absorption coefficients at pumping wavelengths. Nd:GdVO4 has the additional advantage over Nd:YVO4 of a much higher thermal conductivity. For CW lasing at 1.06 um and 1.34 um and intracavity doubling with KTP and LBO, the gadolinium vanadate have produced a higher slope efficiency or optical conversion than Nd:YVO4.

Diffusion bonded crystals consist of one laser crystal and one or two undoped material. They are combined by optical contact method and further bonded under high temperature. Diffusion Bonded Crystal helps to decrease thermal lens effect considerably of laser crystals, provides integral components to make compact lasers. HGO are able to supply various standard assembly and special customized bonding crystals.These diffusion bonded composite crystals have different wedge structures, Brewster angles, etc. It is used to effectively reduce the thermal effect of solid-state high-power lasers.

Co2+:MgAl2O4 Cospinel is a relatively new material for passive Q-switching in lasers emitting from 1.2 to 1.6 μm, in particular, for eye-safe 1.54 μm Er:glass laser, but also works at 1.44 μm and 1.34 μm wavelengths. Spinel is a hard, stable crystal that polishes well. Cobalt substitutes readily for magnesium in the Spinel host without the need for additional charge compensation ions. High absorption cross section (3.5×10-19 cm2) permits Q-switching of Er:glass laser without intracavity focusing both with flash-lamp and diode-laser pumping. Negligible excited-state absorption results in high contrast of Q-switch, i.e. the ratio of initial (small signal) to saturated absorption is higher than 10.

A Neutral Density filter allows a photographer to control the exposure in an image very easily. The filter stops light reaching the camera sensor, therefore allowing us to leave the camera with a higher aperture for a longer amount of time. HG OPTRONICS neutral-density filter is a filter that reduces or modifies the intensity of all wavelengths, or colors, of light equally, giving no changes in hue of color rendition.

Beamsplitter Cubes are constructed by cemented two right angle prisms.  The hypotenuse of one prism is coated with polarization dielectric coating.

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.

Silicon is used as an optical window primarily in the 3 to 5 micron band and as a subsrate for production of optical filters and windows.     Silicon (Si) is grown by Czochralski pulling techniques (CZ) and contains some oxygen that causes an absorption band at 9 microns. To avoid this, material can be prepared by a Float-Zone (FZ) process. Optical silicon is generally lightly doped (5 to 40 ohm cm) for best transmission above 10 microns, and doping is usually boron (P-type) and phosphorus (N-type). After doping silicon has a further pass band: 30 to 100 microns which is effective only in very high resistivity uncompensated material.