Spin‐Flip Raman Laser Is Tunable Infrared Source

An intense laser source has been built which, by varying the applied magnetic field, is smoothly and continuously tunable in the infrared range of 10.9–13.0 microns. Other kinds of tunable sources—parametric oscillators—are available in the visible and near‐infrared (but not infrared). At the APS Washington meeting late in April, Kumar Patel (Bell Labs) described the experiment. He and Earl Shaw shone a 10‐micron $CO2$ laser onto an n‐type indium antimonide crystal and applied a strong magnetic field (varied from 20 to 100 kG) perpendicular to the laser beam.