Laser nearfield measurements

The threshold current density of a laser is an important figure of merit. Threshold current densities are produced using widths derived from the FWHM of optical near field measurements. The infrared light emitted from the facet of the laser is imaged using a lens onto a ccd array, the resulting image being saved as a jpeg (.jpg or .png). Cross sections are taken of the image in the form of intensity versus pixel number and displayed as line profiles, selecting the one with the largest intensity. These are stored as text files. (.txt) Multiple plots can be stored in special text files with headers (.epw) which will open in a normal text editor etc or that will generate a plot if the data is opened using Easyplot graph plotting software. The plots are calibrated against the measured device width.

Research results based upon these data are piblished at http://doi.org/10.1038/nphoton.2016.21