Spectrokinetic characterization of photoactive yellow protein films for integrated optical applications

Szilvia Krekic,Stefka G Taneva,László Fábián,András Dér,Dávid Nagy,László Zimányi

doi:10.1007/s00249-019-01353-8

Abstract

In this paper, the photocycle of the dried photoactive yellow protein film has been investigated in different humidity environments, in order to characterize its nonlinear optical properties for possible integrated optical applications. The light-induced spectral changes of the protein films were monitored by an optical multichannel analyser set-up, while the accompanying refractive index changes were measured with the optical waveguide lightmode spectroscopy method. To determine the number and kinetics of spectral intermediates in the photocycle, the absorption kinetic data were analysed by singular value decomposition and multiexponential fitting methods, whose results were used in a subsequent step of fitting a photocycle model to the data. The absorption signals of the films were found to be in strong correlation with the measured light-induced refractive index changes, whose size and kinetics imply that photoactive yellow protein may be a good alternative for utilization as an active nonlinear optical material in future integrated optical applications.

Highlights

In the past few decades, there has been an ever increasing demand for faster information transmission and data processing
We investigated the photocycle of dry photoactive yellow protein (PYP) films and determined the accompanying light-induced refractive index changes at various relative humidities in order to evaluate their potential integrated optics (IO) adaptability
Our results show that PYP films of controlled relative humidity are good candidates for utilization as active elements in IO devices

Summary

Introduction

In the past few decades, there has been an ever increasing demand for faster information transmission and data processing. Achieving greater speed in state-of-the-art electronic devices requires further miniaturization of integrated electronic circuits and integrating more and more components on a small silicone chip. One of the several alternative solutions investigated is integrated optics (IO), which comprises similar elements to integrated electronics; in IO the information transmission and processing is done solely by optical means. To their electronic counterparts, IO circuits comprise passive and active elements, corresponding to the wires, resistors and capacitors, on the one hand, and the transistors, on the other. The theory of integrated optics and the technology for manufacturing passive IO elements (i.e. miniature waveguides) are well established, and the main challenge is to find or develop materials with suitable nonlinear optical (NLO) properties that can function as active elements in IO circuits

Methods

Results

Conclusion