Underwater Optics

The light scattering, absorption, and refractive index of the underwater environment are different from that of the ground environment. As the depth of the water increases, the pressure increases, and the light becomes darker and darker. Besides, the chemical elements in the water corrodes the materials of the instruments underwater. To better observe the underwater environment, detect underwater resources, and protect underwater instruments, the use of high-precision optical components is essential.

Optical dome is an optical element often used in underwater instruments. Based on consideration of underwater environment factors, the optical materials of underwater domes are usually BK7, quartz, sapphire, etc. The shape of the glass dome is conducive to the underwater movement of the underwater instruments. It enhances the compressive strength and temperature resistance of the instruments. Meanwhile, it improves the corrosion resistance and mechanical strength of the instruments.

Spherical lenses are often used in underwater observation equipment. They are mostly used in objective lenses, oculars and laser collimation systems. An afocal system consisting of a plano-concave lens (used as a waterproof window) and a positive lens corrects distortion, chromatic aberration, and other aberrations. After the precise optical design, the underwater dedicated optical lenses more effectively correct aberrations and eliminate the influence of water media.

Optical mirrors, optical prisms and optical filters are commonly used for underwater lasers. Optical mirrors and optical prisms change the direction of transmission of the light beam. Optical filters filter stray light.

Commonly used underwater optical applications include underwater robots, underwater cameras, underwater probes and underwater laser systems. They are used in the hydrological survey, minefield search, environmental survey, oil drilling, fishery salvage, etc.