Stray light in industrial optics emanates from various sources. These include straight shots especially in reflective systems, single scattered light because of highly reflective detectors or non-optimal baffle design.
Also, stray light can come from ghosting in refractive optics and multiple scatter stray light because of poor baffle design. Although it is impossible to fully eliminate stray light, it can be decreased to a tolerable level.
The popular way of dealing with stray light is through the use of proper design for the optomechanical system. The only way to stop stray light from straight shots is through the use of baffles.
Understanding the principles of light reduction is important if you wish to get accurate measurements as you work with optical devices. This is true regardless of whether you use a microscope, spectrometer, or telescope.
Various techniques have been proposed for the reduction of stray light. The most common is the use of efficient baffles. Others include real-time adjustments of optical systems, the use of light absorbent coatings, and other blocking components.
The main function of baffles together with various other designed systems is to prevent light originating from unintended sources beyond the field of view of the device.
A baffle consists of a tube with vanes in its walls. The goal of the vanes is to decrease the intensity of the light reflecting off the walls. In optical instruments, efficient baffling is important to decrease stray light entering the instrument.
However, the drawback of this method is that it requires precise design, is costly, and adds weight to the device. Black light-absorbing material can be used in the careful design of baffles to decrease the impact of stray light.
Too much stray light inside optical systems can result in a reduction of noise ratio. In other words, it causes major degradation of the optical system. Provided an element of the optical system can decrease stray light from hitting the plane of the image, it can increase the noise ratio.
A black coating is capable of providing a surface that considerably decreases the reflection of light through absorption. Today, some companies offer super black materials used to blacken the optical components.
In the same breath, there are ultra-black coating services for UV sensors, UV absorbers, light detectors, light baffles, and passive infrared detectors. The application of a black coating on optical instruments offers 2 main benefits.
First, it decreases stray light, and second, it improves the surface smoothness and protects it against rust. Besides, if optical instruments are used in extreme temperatures, applying a black coat is a wise move.
Informed by the principles that make it possible to work with stray light thanks to the use of advanced coatings and baffles. These make it possible to considerably decrease the impact of stray light leading to more accurate measurements.
Arguably, the use of black coating is cost-effective compared to the use of baffles in the reduction of stray light. What’s more, it is easy to apply.