Understanding building blocks of photonic logic gates: Reversible, read-write-erase cycling using photoswitchable beads in micropatterned arrays

TL;DR

This study demonstrates reversible, high-contrast photonic switching in micropatterned arrays of photo-switchable beads, enabling binary data processing and paving the way for complex photonic circuit development.

Contribution

We developed a method to create and optimize arrays of photo-switchable polymer beads for reversible optical switching and binary data processing.

Findings

Achieved over 500 reversible switching cycles without contrast loss.

Optimized laser parameters for maximum signal contrast and minimal cross-talk.

Demonstrated binary data writing, reading, and erasing in photonic arrays.

Abstract

Using surface-templated electrophoretic deposition, we have created arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units.