Sterling Precision Optics
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Optical Lenses Materials

Night Vision Optical

  • NVIS

Still Life of Binoculars on RocksNight vision, also known as image intensification, allows humans to see in low to zero light conditions. Night vision is made possible by a combination of two approaches; sufficient spectral range, and sufficient intensity range. A device (NVD) works by collecting photons through a lens (NVIS). Then they pass through a photocathode which converts the photons into electrons. These electrons then pass through a microchannel plate, consisting of millions of closely spaced channels. In here the electrons can hit the walls so they will release thousands of additional electrons. Finally, the multiplied electrons will hit a phosphor screen where they get turned back into light. This light is thousands of times brighter than the original light and is in the visual spectrum of the human eye. The intensified light is in the same orientation as it came in providing a clear view of objects in the dark.

Night vision has many uses. The original use was for military operations. NVDs are now used in security, police work and amateur work. Night vision goggles are especially useful for rescue helicopter pilots because they work even when there are bright light behind them. NVDs work in the near-infrared band at a wavelength of one micrometer. Humans can see between 0.4 and 0.7 micrometers. NVDs work by capturing ambient light usually from the moon and stars. It only takes one star in the sky for an NVD to work.

Night vision can work in one of two ways, active and passive. Passive systems amplify the existing light and active systems rely on an infrared light source. Early NVDs were designed to be used as active systems, as they did not have the sensitivity to operate on ambient light. Active systems are commonly used today in closed-circuit television security and on many home video cameras. The military uses passive NVDs over active because infrared illumination is easily spotted and tracked by others equipped with it. Modern NVDs are equipped with infrared illuminator for when there is no ambient light.

Optical Glasses

  • Bk7
  • Crown

Color Filter Glasses

  • Heat Absorbing Glass
 

Night Vision Monocular Optical filters are lenses that transmit certain wavelengths of light. There are many different types of optical filters. Absorptive filters will absorb certain wavelengths of light while letting others through. Dichroic filters do the opposite of absorptive filters; they reflect certain wavelengths and let certain ones through. Dichroic filters' films form a sequential series of reflective cavities that resonate with the desired wave lengths. Other wavelengths destructively cancel or reflect as the peaks and troughs of the waves overlap.

Infrared or heat-absorbing filters are designed to block mid-infrared wavelengths but pass visible light. They are often used in devices with bright incandescent light bulbs to prevent unwanted heating. There are also near-infrared filters which are used in solid state video cameras to compensate for the high sensitivity of many sensors to near-infrared light. Ultraviolet filters block ultraviolet radiation, but let visible light through. Neutral density filters have a constant attenuation across the range of visible wavelengths, and are used to reduce the intensity of light by reflecting or absorbing a portion of it. They are specified by the optical density of the filter.

Heat Resistant Glasses

  • Pyrex
  • Boroflat

Plate Glass

  • From 1 mm to 1 inch

B270 Drawn Crown

  • From 1 mm to 17 mm
 

UV Materials

  • Fused Silica
  • Fused Quartz

I.R. Materials

  • Germanium
  • Zinc Selenide
  • Zinc Sulfide

Zero Expansion Glass

  • Zerodur

Other glass types available upon request.

Sterling Precision Optics