Analysis of mode-hop free tuning of folded cavity grating feedback lasers.

We analytically study an external cavity laser structure including a folded cavity. A steering mirror is utilized in the folded cavity to deflect the intracavity laser beam. A mode-hop free tuning range of ∼400  GHz can be achieved by control of the steering mirror, and a fast tuning rate is expected because of the small mass of the steering mirror. This technique has potential for applications in spectroscopy for turbulent media, especially in the mid-infrared region.