Optical glass neutral density filters

Colored glass filters are optical components that control incident wavelength by distributing an optical absorbing substance in glass.

Longpass filters are ideal for a variety of applications, such as gas monitoring, temperature, sensing, thermal imaging and motion sensing, etc. Longpass filters block shorter wavelengths and transmit longer wavelengths. Blocking can be from reflectance, absorption or a combination. Transmission in the pass band can be enhanced with an antireflection coating on the second surface.

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.

IPL Filter is the key optical element for IPL (intense Pulsed Light) machine, which blocks the UV wave and transmits the useful wave from 400nm to 1200nm for laser equipment, such as photo-rejuvenation hair removal, vascular and acne treatment, skin rejuvenation.

The Rhomboid prism application for rhomboid-prism is controlling and redirecting the optical path without affecting the image direction. They can be used to displace an optical center line for light beam folding and stereoscopic systems of different sizes.

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.

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.    

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.