Realization of multiphoton lasing from carbon nanodots microcavities
The use of organosililane chains to link carbon nanodots (CDs) through organosililane surface functional group is proposed to improve the efficiency of multiphoton absorption. As a result, large absorption coefficient of 1.16×10–6cm5/GW3 is obtained and four-photon luminescence under 1900 nm excitation is observed from the CDs at room temperature. Furthermore, CDs laser, which demonstrates random lasing under three-photon (i.e. 1400 nm) excitation, can be realized by sandwiching CDs film between a quartz substrate and a dielectric mirror. The formation of strongly confined microcavities, which are arisen from the non-uniform distribution of refractive index inside the CDs film, is attributed to the realization of lasing emission.