When incoming photons arrive at one of the wires first it results in Mie scattering which essentially means that the absorption capability of the second wire is affected. Since both wires are optically coupled and the photocurrent is proportional to the angle of the incoming light the angle can easily be determined.
The researchers, however, took their experiment a step further and built two angle detections. The two detectors were then separated by a known distance and using the differential current readings from each sensor they were able to triangulate the light source and therefore know its distance. According to their triangulation experiment distances from a light source can be determined with an accuracy of a centimeter within a range of 10 meters. Interestingly, this method of range finding is considerably less complex than using high-speed electronics which fire a laser beam and then time the return journey.
For example, LiDAR systems use a rotating mirror and a laser along with high-speed electronics to time the return journey of a laser.
Angle of incidence (optics)
While this method is reliable and already in use, it generally requires bulky parts such as motors and mirrors , as well as having a minimum detection distance. Nanowires, however, may not have a minimum distance measurement due to the fact that they operate around real-world photon behavior as opposed to a CPU and a counter.
A LiDAR system that used nanowires would still need a rotating mirror with a laser but there would be no need for a CPU with timer and results could be read with even the simplest microcontroller. A fixed laser could also be used, which would act as a laser range-finder but the entire sensor and laser setup could easily fit into a single IC package. Angular detection, as stated before, could be potentially useful for photography.
While professional photographers typically use manual focus, most novice users will use autofocus. Autofocus can be achieved using multiple methods. A simple example of one such method involves contrast and sharpness detection whereby an object that is to be focused should have a sharp change in contrast between it and the background.
The lens is adjusted until the largest change is detected, at which point the camera considers the object in focus. However, angular detection sensors could provide both angular and direction information that would tell the camera exactly how far away the subject is.
AN ANGLE OF LIGHT IS AN ANGEL OF LIGHT
Therefore, instead of guessing if the image is in focus, the camera would be able to adjust the camera focus setting these settings are often shown as a distance to object. This could provide a path towards lens-less cameras. This functionality also has ramifications for robotic vision applications, providing additional data for processors to utilize in, for example, autonomous vehicle guidance. Augmented reality, which relies on sensor data to populate graphics overtop the existing environment, could see a revolution as more advanced focusing and distance detection allow more immersive augmented experiences.
Light Reflection and Refraction
Featured image includes image of nanowires used courtesy of Stanford University. Load More Articles. Angular detection is something difficult to accomplish with modern sensors. Learn More About: nanowires Silicon si nanowires angle detection angle measurement photon angle mie scattering robin mitchell. You May Also Like:. Robin Mitchell. Note that while these abbreviations are commonly used, the angles associated with these vary slightly from manufacturer to manufacturer.
These are typical beam angles spread abbreviations.
For most domestic household ceiling fitted appliances a beam angle in the degrees will be sufficient given the standard height of ceilings and the range, spread and number of light bulbs in the area. Please also note that the wattage, type of light bulb and colour used will also determine the beam angles available. Please move your mouse over the interactive picture below, left for a narrower beam angle, right for a wider beam angle.