Crystals and optics processing services

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.    

A band pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range, and it’s used to selectively transmit a portion of the spectrum while rejecting all other wavelengths.

Nd:YAG is the earliest and most famous laser host crystal. Since it combines great advantages in many basic properties,Nd:YAG is the ubiquitous presence for near-infrared solid-state lasers and their frequency-doubler, tripler, and higher order multiplier. It is widely used in industrial, medical, military and scientific fields.. Nd:YAG crystals are wildly used in all types of solid-state laser systems-frequency-doubled continuous wave, high-energy Q-switched, and so forth.Its good fluorescent lifetime thermal conductivity and physical strengths makes it suitable for high power lamp pumped laser.

Invented by H.W. Dove, Dove Prisms are also known Reversion prisms.  When the prism is rotated about its length axis, the image viewed through the prism rotates at twice the prism rotation rate.  This is an unusual and sometimes useful property for special applications. Entry and exit faces are anti-reflection coated.

α-BBO (α-BaB2O4) is a negative uniaxial crystal which has large birefringence over a broad transparent range of 190nm to 3500nm. α-BBO is an excellent crystal especially in UV and high power applications. The physical, chemical, thermal, and optical properties of alpha-BBO crystal are similar to those of Beta-BBO. However, there is no second order nonlinear effect in alpha-BBO crystal due to the centrosymmetry in its crystal structure and thus it has no use for second order nonlinear optical processes. Instead, alpha-BBO is widely used for fabrication of polarizers, polarizing beam displacers, phase retarders, birefringent plates, and time delay compensators especially those for UV and high power lasers.

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.

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.

Plano-convex circular cylindrical lenses are useful for line imaging or uni-axial magnification in a wide range of applications. These lenses may be combined with other lenses to form complex imaging systems.