2. Introduction to advanced optical imaging#
2.1. Motivation#
Why study optical imaging systems? Advanced optical imaging systems are everywhere: microscopes, lithography systems, holographic displays, and computed tomographic imaging systems. These imaging systems are of paramount importance in science, biology, medicine, and industry. For the creation of the best possible images it is of key importance that these imaging systems perform at their limits in terms of resolution, contrast, and signal amplitude.
To understand the performance of optical imaging systems these systems need to be described in terms of wave optics. In contrast to the geometrical optics description of optical systems one needs to take into account the full wave nature of light to understand the performance of these systems. The wave nature of light gives rise to diffraction, which poses a fundamental limit on the obtainable spatial resolution.
The wave nature of light in optical imaging systems is described by what is called Fourier Optics. This is a description of the optical wavefield in spatial Fourier components. Fourier Optics gives a solid framework to describe and understand optical imaging systems as linear space-invariant systems that operates on the input. In the spatial domain this is described by a convolution of the image with a point spread function. In the frequency domain the imaging systems operates as a frequency filter by means of a transfer function.
2.2. Course topics#
After an introduction into the concepts of Fourier optics in this online book we will see how they play a role in various imaging systems such as:
wide field microscopy
phase microscopy
confocal microscopy
structured illumination microscopy
super resolution microscopy
adaptive optics
holography
optical coherence tomography
Note this book is under development and that not all of these topics have yet been added to the book.