Extended temperature tuning of an external cavity diode laser

We describe the construction and operation of an external cavity diode laser in which the diode is cooled to -45 °C. This technique allows us to pull the wavelength of a nominally 782 nm diode to operate at 766.7 nm, a change of over 15 nm. The important aspects of our design are its ease and low cost as compared to other designs of changing the operating wavelength of laser diodes. We provide background information on thermal design with multiple TECs so the reader can extend this example for use in their own applications.