Electron energy loss spectrometry mapping

Among electron beam microanalytical techniques, electron energy loss spectrometry (EELS) offers unique advantages in terms of information content, sensitivity, limits of detection. This paper describes new methods and tools for acquiring families of spectra over many pixels on the specimen, i.e. spectrumimages, and for processing them. Applications in different fields of research, both in materials science and in life sciences, demonstrate the potential impact of the technique for characterizing nano-sized structures.     

Laser action and excited state absorption of chlorophyll-a

Stimulated emission of chlorophyll-a is observed in the spectral range around 670 nm. The calculated wavelength at the threshold turns out to be shifted by 20 nm towards longer wavelengths. To clarify this discrepancy, extrinsic-loss variations at the laser as well as measurements of nonlinear are carried out. The results indicate an excited singlet state absorption (σ > 10¹⁷ cm² within the range from 670 to 700 nm).