AN ABSOLUTE DIODE LASER WAVELENGTH STANDARD

PHASE I CONSISTS OF A RESEARCH AND DEVELOPMENT PROGRAM TO DEMONSTRATE THE FEASIBILITY OF STABILIZING THE FREQUENCY OF AN INEXPENSIVE DIODE LASER TO WITHIN 1 MHZ OF THE CENTER OF AN ATOMIC ABSORPTION LINE. A KEY TO THE APPROACH WILL BE THE USE OF A FREQUENCY DISCRIMINATOR BASED ON THE ZERO-CROSSING OF THE ANOMALOUS DISPERSION CURVE AT CENTER LINE. THIS WILL ALLOW ACTRIVE STABILIZATION OF THE LASER FREQUENCY WITHOUT THE USUAL NEED TO DITHER ITS FREQUENCY. THE ZERO-CROSSING WILL BE SENSED USING A STABLE INTERFEROMETER AND A UNIQUE TRIPHASE DETECTION TECHNIQUE WHICH IS UNAFFECTED BY LASER INTENSITY FLUCTUATIONS. IF SUCCESSFUL, THE TECHNIQUE CAN BE USED WITH VIRTUALLY ANY LASER AND PROMISES TO REDUCE THE COST OF LASER FREQUENCY STABILIZATION, AND TO SIMPLIFY THE PROCESS AND MINIMIZE THE POWER CONSUMPTION. FREQUENCY-STABILIZED LASER DIODES, BECAUSE OF THEIR INHERENTLY LOW COST, HIGH EFFICIENCY, AND WIDE TUNING RANGE, ARE IDEAL LIGHT SOURCES FOR THESE APPLICATIONS.