メタン吸収線を基準にした3.39μm He-Ne レーザーの波長安定化
1972 年 41 巻 12 号 p. 1300-1307
詳細
1972 年 41 巻 12 号 p. 1300-1307
An infrared frequency standard stabilized with respect to the absorption line of methane has been constructed and studied. An extra-cavity cell of CH4, which is kept at the triple point or the boiling point of nitrogen, is used to stabilize the 3.39μm 3He-22Ne laser. 22Ne line is shifted by pressure effect and broadened by Zeeman effect resulting in a flat top in the gain curve at the center of the absorption line. First derivatives of the output power passing through the cell show approximately constant slopes near the line center in the CH4 pressure range 13-70 Pa (0.1-0.5 torr), and the control signal is not sensitive to the CH4 pressure in this range. Two servo systems with and without an integrator have been tested, and from the traces of the error signal, fluctuations of the stabilized frequency are estimated to be ±2×10-11 in a day and ±8×10-11 in an hour respectively.
