Stimulated Emission Thresholds of Ethanol Solution of Coumarin-30 Dye with Incorporated ZnO Nanoparticles Upon Irradiati
- PDF / 608,571 Bytes
- 4 Pages / 595.276 x 790.866 pts Page_size
- 78 Downloads / 147 Views
STIMULATED EMISSION THRESHOLDS OF ETHANOL SOLUTION OF COUMARIN-30 DYE WITH INCORPORATED ZnO NANOPARTICLES UPON IRRADIATION WITH FEMTOSECOND LASER PULSES P. A. Babushkin,1,3 A. V. Burnashov,1 V. A. Donchenko,2 Al. A. Zemlyanov,1,3 V. K. Oshlakov,1 R. V. Ryambov,3 and A. V. Trifonova3
UDC 537.523
Experimental results of measuring the threshold power density of stimulated emission in coumarin-30 dye solutions with ZnO nanoparticles upon irradiation with femtosecond laser pulses are presented. It is shown that the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles upon irradiation with femtosecond laser pulses are approximately by 3 orders of magnitude higher than the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles irradiated with nanosecond laser pulses. Keywords: nanoparticles, femtosecond pulse, stimulated emission threshold.
The development of laser sources in the last few years is connected with their miniaturization and creation of highly effective active media. One of such lasers is a stochastic laser known in the foreign literature as a random laser. The active medium of this laser is a composite of laser-active molecules and nanoparticles of various materials. The possibility of laser radiation generation in randomly-inhomogeneous active media was first theoretically substantiated by V. S. Letokhov [1], who proposed a possible mechanism of feedback formation in an amplifying medium at the expense of strong scattering. In 1986, V. M. Markushev demonstrated this effect experimentally for dielectric powder samples activated by neodymium ions [2]. In 1994, N. M. Lawandy [3] demonstrated the isotropic laser emission of solutions of Rhodamine 640 (R640) with scattering TiO2 nanoparticles. In his experiment, the width of the secondary emission spectrum sharply narrowed down from 70 to 4 nm after achievement of the threshold pump energy. Stochastic lasers find application in many branches of science and technology, such as illumination [4, 5], imaging [6], sensors [7–9], and information technologies [10]. Among the special properties of the random laser compared to lasers of other types are the angular dependence of radiation and the possibility of wavelength tuning in a wide spectral range. Radiation of the random lasers is distributed over the entire solid angle 4 π. Such angular distribution of radiation is ideally suited for displays. A particular advantage of the random lasers is that they can be prepared as suspensions and used as coatings on an arbitrary shaped surface [6]. Drane et al. [11] reported that the stimulated emission thresholds with femtosecond pumping were by two orders of magnitude lower than with nanosecond pumping. In [11] Red fluorescent protein DsRed2 was used as nanoparticles, and it was concluded that the superfast pumping could be preferable for lasing of biological media with low damage threshold of biological tissues.
1
V. E. Zuev Institute of Atmospheric Optics of the Siberian Branch of the
Data Loading...
