Stabilization of VCSEL laser source for absolute laser interferometry

We describe a new laser head with Vertical Cavity Surface Emitting Laser (VCSEL) diode for absolute laser interferometry with Michelson interferometer. The VCSEL lasers at 760 rim with mode-hop free tuning range above 1 nm are affordable now. The VCSEL's are fabricated as circulary-symetric lasers; the circular aperture is of particular value as it implies a circular beam profile. The linewidth and the optical noise of the VCSEL laser diode depend on the stability of the current source controller and on the quality temperature control system. We developed a digital temperature control system with temperature stability below 1 mK and high stability current source controller.