Coherent Optical Processor [Photonics]

[Tsunami]

In my course on Microphotonics there is a brief mention of a coherent optical processor system. My problem is I don't exactly know what it's for.

Basically, what is said that a transparent input image (like a photograph) is lighted monochromatically and then focussed by a lens to a spot with another transparent layer with a given transmission function. If the light transmitted through this spot is again refocussed, the convolution of these two transmission function will be given. (At least, I think, maybe there's a phase factor I'm missing?)


Anyway, at this point, the intensity can be given as:


I(x3,y3) = K* abs[ (g*h)(x3,y3) ]^2

where

(g*h)(x3,y3) = int(int( g(eps,eta) h(x3-eps,y3-eta), eps=-inf..inf),eta=-inf..inf)



So

So I think that this thing can be used to 'clean' an image up, by making h a filter function. However, I've been reading some on the net, and it appears that such a processor can also be used to reconstruct an image. How is that possible?

2.
Also, I've read that nowadays, there are other and better techniques for stuff like this, and that one can even use incoherent light. Can anybody tell me something about that?

 

[Aaron Bex]

Yes, there are now other techniques that can be used for image processing. These include digital image processing, which is done through software, and optical image processing, which can use incoherent light to process images. Incoherent light is less efficient than coherent light, but it is often easier to use due to its lack of phase information. Digital image processing uses algorithms to manipulate the pixels in an image, while optical image processing involves passing light through a series of lenses, filters, and mirrors to manipulate the image.

 

[astrokreng]

As a scientist in the field of photonics, I can provide some insight into the purpose and capabilities of a coherent optical processor.

First, let's start with the basics. A coherent optical processor is a device that uses coherent light, meaning that the light waves have the same frequency and phase, to perform various operations on an input image. This device is typically used in the field of optics and photonics, where light is the main medium of study and manipulation.

Now, onto your specific questions. The purpose of a coherent optical processor is to perform operations on an input image, such as filtering or reconstruction. The process you described, involving the convolution of two transmission functions, is a common operation in signal processing and can indeed be used to filter an image. By choosing a specific transmission function as your filter, you can remove certain features or noise from the input image to improve its quality.

However, a coherent optical processor can also be used for image reconstruction. This is possible because of the unique properties of coherent light. Since the light waves have the same phase, they can be combined in a way that allows for the reconstruction of an image that has been distorted or lost during transmission. This process is known as holography and is commonly used in imaging and data storage.

As for your question about using incoherent light, this is also possible but with some limitations. Incoherent light does not have the same phase as coherent light, so it cannot be used for operations that require precise interference patterns. However, incoherent light can still be used for basic image processing and does have some advantages, such as being easier to produce and manipulate.

In conclusion, a coherent optical processor is a powerful tool in the field of photonics that can be used for various operations on an input image, including filtering and reconstruction. While there are other techniques available, the use of coherent light allows for precise and efficient processing of images.