The estimation of the Point Spread Function (PSF) of an imaging system is important for various post acquisition processes. The PSF can be estimated by knowing the optical arrangement of the imaging system or can be obtained by using a point object. Both the techniques have their own limitations. In this paper we propose a new PSF estimation technique based on a target that can be reconfigured programmably. We will show that a target with different illumination areas can be imaged to establish a relation between the image plane and the object plane via a PSF. The relation thus allows one to estimate the PSF of the imaging system.
The high resolution applications of a laser scanning imaging system very much demand the accurate positioning of the illumination beam. The galvanometer scanner based beam scanning imaging systems, on the other hand, suffer from both short term and long term beam instability issues. Fortunately Computer generated holography based beam scanning offers extremely accurate beam steering, which can be very useful for imaging in high-resolution applications in confocal microscopy. The holographic beam scanning can be achieved by writing a sequence of holograms onto a spatial light modulator and utilizing one of the diffracted orders as the illumination beam. This paper highlights relative advantages of such a holographic beam scanning based confocal system and presents some of preliminary experimental results.
In confocal microscopy the polarization of the illumination beam plays an important role in determining the orientation of the fluorescent molecules being illuminated. The efficiency of the excitation depends on the angle between the excitation electric field and the direction of the molecular dipole. In order to determine the orientation of the fluorescent molecules in the focal plane the molecules are to be excited using two mutually orthogonal electric fields. In this paper we show how a computer generated holography technique can be implemented using a ferroelectric liquid crystal spatial light modulator to conveniently obtain two images of the same target once with an X polarized illumination beam and another with a Y polarized illumination beam.