Abstract: A single frequency stabilized laser which is useful in long base line interferometers, optical inspection devices and other applications requiring a single-frequency laser source is provided having a cold-cathode and a hard-sill glass laser tube. A resistance coating, for example, Aquadag, covers the exterior surface of a laser tube which is mounted on a metallic base member. A small power supply which energizes the resistance coating for serving as a heater is coupled to this coating by fine wires, embedded in silver epoxy, for heating the glass laser tube to stabilize the frequency of the tube and eliminate mode changes in the operation thereof. A temperature sensor is provided for monitoring the temperature of the tube and is coupled to a temperature controller which controls the power supply for controlling the current applied to the resistance coating on the tube via the fine wires.