Vol. 18, issue 01-02, article # 9
pdf Zemlyanov A. A., Geints Yu. E. Laser-induced spontaneous fluorescence of molecules from a microparticle. // Atmospheric and oceanic optics. 2005. V. 18. No. 01-02. P. 53-60.Copy the reference to clipboard
Abstract:
Spontaneous fluorescence of molecules induced by laser pulses of different duration in a microparticle is considered theoretically. Equations describing the dependence of the power and the spectral cross section of a single-photon spontaneous fluorescence from the microparticle on the particle volume, the concentration of active molecules, and the spectral characteristics of the incident and emitted light are obtained by the method of open-resonator theory with the field vectors expanded in series of quasinormal vibrational eigenmodes of a dielectric sphere. It is shown that the spontaneous fluorescence cross section for the particle excited by a short ( (tp << ts, where ts is the characteristic time of spontaneous fluorescence) and long (tp >> ts) laser pulses has the same form provided that it is determined from the energy and power relations, respectively. At the same time, the spectral cross section of a single-photon process can exceed by more than ten times the cross section of spontaneous emission from the same volume of a bulk medium. This excess is proportional to the product of the factors accounting for the focusing properties of the particle and its characteristics as a dielectric microresonator.