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Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it.Optics usually describes the behaviour of visible, ultraviolet, and infrared light.

When you choose the appropriate optical components, it is necessary to calculate more about your actual application, and their different properties. Besides of cost, to express or improve the optical performance is our final destination.

In optical systems, optical lenses are necessary and the most fundamental components. They are transparent and allow light transmit. According to actual application, they are designed to control the light directions, further to its path, the focus and magnification. They could be widely used in cameras, telescopes , projector and such optical instruments.

Of course, it is important to understand the basic light principles. As we all know, Light travels in a straight line until it hits a surface, where it could be absorbed, reflected, or refracted. When light passes through a material with a different refractive index, refraction occurs and causes direction changing. This phenomenon is what allows lenses to bend and focus light.

An optical lens is made of a material with a specific refractive index, such as glass or plastic. It has two surfaces, called the convex (bulging outwards) and concave (curving inwards) surfaces. When light passes through the lens, it is refracted twice: once at each surface. The amount of refraction depends on the shape and curvature of the lens, as well as the refractive index of the material.

The behavior of light passing through an optical lens can be mathematically described using the lens equation: 1/f = 1/v + 1/u, where “ f “ is the focal length of the lens, “ 1/v” is the distance of the object from the lens, and “ 1/v” is the distance of the image from the lens. This equation helps to predict how the lens will affect the path of light and where the image will be formed.

While optical lenses’ design is a complex and iterative process, many aspects, such as size, weight, performance, cost, need to put into consideration.

VD stands for “Abbe number” . It is one material’s dispersion measurement. In other words, how much the refractive index of the material varies with wavelength. And use Abbe number to show different refractive index. With higher Abbe number, this material has larger dispersion. That is to say, such a material separates different colors of light more strongly. On the contrary, With lower Abbe number, this material has smaller dispersion. That is to say, such a material separates different colors of light less strongly.

ND stands for ” Refractive number” . It is a measure of how much light is bent when it passes through one kind of material. With higher Refractive index, this material bends light more strongly. On the contrary, With lower Refractive index, this material bends light less strongly.

Such two values are important, optical glass is often characterized by them. since they affect the optical glass’s behaviour in one optical system. Take one optical lens made of glass with high VD value as one example, it will suffer from chromatic aberration, which means that different colors of light will focus at slightly different points, resulting in blurred images. In order to reduce chromatic aberration, the glass with low VD is often used.

Similarly, the refractive index of the glass affects the power of the lens. Lenses made of glass with high refractive index can be made thinner and lighter for the same optical power as lenses made of glass with low refractive index.

Of curse, exact and appropriate choice are decided by actual application and system.

Mentioning Optical Prisms, we all know that they are kinds of transparent optical elements with flat, polished surfaces which could refract, reflect, or disperse light. They are widely used in optics and photons applications, such as in cameras, and telescopes, to manipulate the path of light.

Dating back to the ancient times, Sir Isaac Newton conducted experiments on the nature of light in the late 1600s. In one famous experiment, Newton used a prism to show that white light is actually made up of a spectrum of colors, which can be separated and displayed as a rainbow. This discovery laid the foundation for the field of spectroscopy, which is the study of the interaction between light and matter.After Newton’s discovery, prisms began to be used in a variety of optical instruments, including cameras, binoculars, and telescope and so on.

Optical prisms can refract and/or reflect light. When light enters the prism at an angle, it is refracted by the prism’s surface, causing changing the light direction. The amount of refraction depends on the angle of incidence and the refractive index of the prism material. Different colors of light have different wavelengths, which means they refract at slightly different angles. This property of light is what allows prisms to split white light into its component colors, creating a rainbow effect. They also can be used to reflect light, and invert an image without changing the orientation, widely used in porro prism type binocular.

Of course, there are many kinds of optical prisms, such as triangle prism, right angle prism, porro prism, dove prism and so on. Exact and appropriate choice is decided by actual application and system.