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.

HGO grows Pr:YLF laser crystals using Czochralski technology. Pr3+:YLF has been found as promising laser material for producing visible lasers directly and UV lasers through intracavity second-harmonic generation. Very few laser materials have the necessary properties for the realization of lasing in the visible spectral range. Trivalent praseodymium (Pr3+) is known to be an interesting laser ion for use with solid-state lasers in the visible spectral range because of its energy levels scheme, providing several transitions in the red (640 nm, 3P0 to 3F2), orange (607 nm, 3P0 to 3H6), green (523 nm, 3P0 to 3H5), and dark red (720 nm, 3P0 3F3+3F4) spectral regions.

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.

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.

Potassium Gadolinium Tungstate (KGd(WO₄)₂) crystal is an excellent stimulated Raman laser crystal with characteristics such as a wide light transmission range, good thermal conductivity, high damage threshold, large Raman shift coefficient, and high Raman gain. It can maintain high conversion efficiency and beam quality during the Raman frequency conversion process. The KGW crystal can withstand high pump power and is suitable for pump lights of various wavelengths, making it widely used in Raman lasers, laser frequency conversion, medical imaging, photodynamic therapy, environmental monitoring, spectroscopy research, material processing, and other fields.