Highly sensitive and ultrafast light modulation with a vanadyloxophthalocyanine-doped composite polymer guided wave mode device

Abstract

We propose a guided wave mode (GWM) device with prism coupling, which is composed of a low-refractive-index polymer layer and a vanadyloxophthalocyanine-doped polymer layer. Reflectance dips due to the GWM were observed at specific incident angles depending on the wavelength and the thickness of each layer. The reflectance at the GWM can be controlled by the real part (n) and/or the imaginary part (k) of the complex refractive index of the waveguide layer. The k dependence of reflectance showing a minimum of almost zero at a certain value defined as kc was confirmed in the visible to near infrared region. The kc value varies linearly with the intensity of the evanescent wave. Highly sensitive and ultrafast control of reflection in the GWM geometry was demonstrated by the photoinduced complex refractive-index change upon femtosecond laser excitation of vanadyloxophthalocyanine.