Schematics of power-gated optical holeburning setup for nanoparticles at . The setup uses a double-beam normalized optical detection system. Lock-in amplifiers A and B detected the signal in the reference and the sample beam. A signal divider (A/B), a data acquisition card (DAQ), and a personal computer (PC) with LABVIEW software were used for processing the spectra.
Emission (a) and excitation (b) spectra of MgS:Eu. The ZPLs appear as intense and sharp features at . Note that the microparticle samples used for the emission and excitation spectra are not the same. To show the broadening effects in nanoparticles, in (b) the ZPL is compared with the broadest ZPL observed in microparticle samples.
(a) Emission spectra of transition in nanoparticles prepared in different buffer gas pressures, as shown in spectra 1–4. The higher the pressure, the smaller the size of nanoparticles produced. (b) DWF as a function of pressure (logarithmic scale). The deviation of the point at is attributed to oxygen contamination that results in a Eu–O center with a ZPL at .
Linewidth of the ZPL as a function of the pressure of the ambient gas in the PLD chamber for the data presented in Fig. 3(a), the higher the pressure , the smaller the size of nanoparticle produced and the narrower the ZPL. The for the ZPL increases with the size of nanoparticle. The line fit represents the fit to the data.
Particle size distribution in a typical PLD run without any further size selection. The average particle diameter is .
The emission and the spectral holeburning (inset) spectra for nanoparticles. The spectral holes were burned in the ZPL of the transition and had a typical width of .
Temperature broadening of the spectral hole: the triangles represent the data for nanoparticles, the solid line shows the dependence, and the dashed line the best possible fit for .
Schematics of the mechanism of power-gated holeburning in transition of . act as deep traps. The solid arrows represent optical excitations and the dashed arrows represent electron capture. Both burning and gating photons come from the same laser. The hole generated in the inhomogeneous line is shown on the left.
Article metrics loading...
Full text loading...