"An ECDL provides a stable single-frequency, single-mode laser output using an external cavity created between the laser diode and a diffraction grating. The external cavity, together with the internal cavity within the laser diode, provides a small range of wavelengths that can be scanned over using a piezo to perform laser absorption spectroscopy.  For this project, a design for the overall layout of the components needs to be created as well as controllers to stabilize the current and temperature of the diode."