非断熱励起による近赤外励起可視発光と応用

抄録

We observed visible light emission in the wavelength range (λ = 600-690 nm) from aggregated 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) dye molecule microcrystals pumped by infrared light (λ = 805 nm). This visible light emission occurs through the nonadiabatic transition processes induced by the optical near field at the microcrystal surface. From an observation of the dependence of the emitted light intensity on the excitation intensity, we found that the visible light emission is originated both from the nonadiabatic one-step and two-steps transition processes. The frequency up-conversion efficiency for our DCM microcrystals was experimentally estimated to be higher than that of the second harmonic generation from a potassium dihydrogen phosphate (KDP) crystal.