Compensation of the capacitance effects produced by a HPDLC cell on a voltage amplifier

Abstract

Holographic polymer-dispersed liquid crystal (HPDLC) is a composite electro-optic material, able to exhibit holographic volume regime and whose refraction index can be varied by the application of an electric field. This electrical tunability combined with volume regime offer the possibility of many interesting photonics applications such as in diffraction optics, reflection display, and in optical interfaces and interconnects. In principle H-PDLC cells need high voltage AC signals, typically 1 kHz bipolar waveforms, to be tuned, therefore a high voltage amplifier in combination with a waveform generator is necessary. In this work we provide evidence of limitations in the voltage range applied with our voltage amplifier due to the capacitance of the HPDLC cell. The theoretical modelling, done using OrCAD-PSpice® software confirms the experimental results. Finally we show how this limitation can be overcome.