A spectroscopically resolved photo- and electroluminescence microscopy technique for the study of high-power and high-brightness laser diodes

A novel and advanced characterization technique is described for performing optical studies of the luminescence properties of materials. It was developed for the investigation of semiconductor materials, including semiconductor laser diodes and photonic integrated circuits. A quantitatively calibrated, spatially and spectrally resolved imaging technique is described, which is based upon the technologies of photoluminescence microscopy and photoluminescence spectroscopy. The principles of the spectroscopically resolved photo- and electroluminescence microscopy techniques are outlined in this paper, and the developed instrument is described in detail. Design calculations used to select and set up the experimental apparatus are presented, and results are found to compare well with this analysis. Various experimental measurements are used to demonstrate the performance of the new instrument. The study of strain and defects in high-power laser diodes is presented as one of the more challenging applications of the new technique. The results presented demonstrate the ability of this technique to image photoluminescence shifts occurring in the substrate of packaged laser bars, enabling the investigation of strain, defects and their evolution with aging. Other applications of the technique include the spectroscopic measurement of near- and far-field patterns and virtual sources of laser diodes, investigations of spectral hole burning and optical scattering processes in lasers and photonic integrated circuits, and studies of organic LEDs. In the future, applications are also envisaged in medicine and the biological sciences.