Do you know what an optical prism is?

Definition of an optical prism

An optical prism is a solid, transparent element that has the characteristic of refracting light. When light enters through one surface, it can be manipulated and emitted through the other side. Therefore, there is a certain relationship between the precision polished surface and the angle of its surface, which ensures that the prism plays a key role in reflecting light.

Optical prisms are essential for redirecting light at specific angles, allowing it to reflect, bend or change the direction of an image. They can also separate light into its component wavelengths or polarizations. A famous historical use of prisms was Isaac Newton, who used a simple prism to scatter light into the full spectrum, proving that white light is a mixture of various colors. This scattering principle is still vital in modern applications such as spectrometers and refractometers. Conversely, prisms can combine light beams, demonstrating their versatility.

Optical prisms are made of high-quality materials, including fused silica, filter glass, germanium, silicon, and zinc selenide. The company also offers custom and standard coatings through its in-house facilities, with anti-reflection designs, reflectors, beam splitters and high laser damage threshold coatings, ensuring optimal performance in a variety of applications.

Optical Prism Types

Dispersive Prisms

Among them, the triangular prism is also a type of dispersive prism, which separates light into its spectrum due to the different refractive indices of different wavelengths. According to Snell’s law, longer wavelengths, such as red (656.3 nm), are refracted less than shorter wavelengths, such as green (587.6 nm) or blue (486.1 nm), resulting in color separation. The degree of dispersion depends on the dispersion curve and geometry of the prism, and equilateral prisms are commonly used in spectroscopy and telecommunications.

Displacement Prisms

These prisms maintain the direction of the beam while changing its relationship to the normal. The rhombus prism is a typical example of this type, which displaces the incident beam without changing its handedness, making it suitable for binoculars, rangefinders, and laser instruments.

Rotation Prisms

These prisms, such as the Dove prism, rotate a beam of light and its corresponding image. The Dove prism is used in fields such as astronomy and pattern recognition, and rotates the image 180 degrees, producing a left-handed image. On the other hand, the Schmidt prism deflects the light by 45 degrees, producing a right-handed image.

Deflection Prisms

This category includes the half pentaprism and the Amici roof prism. The Amici prism deflects the light path by 90 degrees. degrees, while inverting the image, making them popular in microscope and telescope eyepieces. Coatings on the top surface of the prism can also allow for different angles of deflection. Half-penta prisms deflect light by 45 degrees and are commonly used in Pechan erector assemblies.

It is worth noting that a single prism can serve multiple functions depending on its orientation. For example, a 45°–90°–45° prism (called a right-angle prism) can cause a single reflection, deflecting the incoming light by 90 degrees when the light enters at right angles through one of the 45° leg faces. Alternatively, if the light enters through the hypotenuse face, it becomes a Porro prism, which reverses the direction of the light, allowing the beam to enter and exit from the same face, potentially inverting the image depending on its orientation.

Similarly, a right-angle prism can also be used as a Dove prism, rotating the image by 180 degrees, and can also be inverted or inverted depending on the position of the prism. This adaptability makes optical prisms a key tool in a variety of optical systems and applications.

Summary

We Mok Optics offers many types of optical components. If you have any questions about these products, please feel free to contact us.

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