The present disclosure provides meroduplex ribonucleic acid molecules that decreases or silences target gene expression. The light guide plate includes a first surface, a second surface, and a light incident surface connecting the first surface and the second surface. After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light.