Fig. 2: Chain-conformation patterning in PFO films.

a Schematic illustration of the laser-patterning process. Colours and symbols as in Fig. 1. ITO layer is shown by a purple stripe; yellow arrows indicate diffusion of donor. b Confocal PL microscopy images of β-phase lines patterned in glassy PFO using laser excitation at 785 nm, constant writing speed v = 5 µm s⁻¹ and laser power P = 10–50 mW (as indicated). PL intensity is shown at 438 nm to spectrally select β-phase emission. Also shown in b is an exemplary Raman intensity ratio image (right panel) of the line patterned using P = 30 mW, recorded as the ratio of Raman intensities, r_R, at 1257 and 1606 cm^–1, from which local β-phase fraction is estimated. c, d FWHM of β-phase line patterns (black dot, left ordinates) and maximum induced β-phase fraction in the patterns (red triangle, right ordinates) as function of (c) laser power for v = 5 µm s^–1 and (d) writing speed for P = 20 mW.