Abstract

 Semiconductor laser diodes are efficient electrical to optical power converters operating over a wide wavelength range. We developed high-power infrared laser diodes and laser arrays suitable for optical pumping, spectroscopy and biomedical applications. Some of these applications require high output power delivered into a narrow spectral range. The compact size of laser diodes is preferable and convenient in different implementations, but it leads to significant overheating in high power operations. The inherent properties of semiconductor materials result in a red-shift of laser emission spectrum with temperature. This thermal drift of the laser emission spectrum can lead to misalignment with the narrow absorption bands of illuminated materials. We have developed an experimental technique to measure the time-resolved evolution of the laser emission spectrum. The spectrum evolution was measured using a SPEX-500M grating monochromator equipped with a linear 256-pixel InGaAs photodetector. This technique allows measuring the laser spectrum over a 40-nm wide range without rotating the diffraction grating. The data obtained from the emission spectrum measurements have been used to optimize the laser device design.