Undergraduate optical experiments using simple liquid crystal displays

Abstract

We propose here the use of few pixel liquid crystal displays (LCD) to be used in optics experiments. Commercial LCD displays used in electronic sensors have a simple electronic, can be addressed by conventional wavegenerators and are, in addition, very cheap. These devices are governed by the same basic principles as the recently developed high-resolution crystal displays. The physical models that explain the behaviour of the LCD are very interesting from an educational point of view. The predictions arising from different models can be compared by performing simple photometric measurements. By means of interferometric architectures it is possible to measure the phase modulation introduced in the interference pattern when different voltages are applied to the LCD. These devices have the ability of provide a controlled phase modulation, a feature that renders them very useful devices for phase shift interferometers. The experiences presented here can be performed in an undergraduate laboratory with a basic optical equipment.