S. Ezekiel

Nonlinear laser spectroscopy

1. Introduction.- 2. Elements of the Theory of Resonant Interaction of a Laser Field and Gas.- 3. Narrow Saturation Resonances on Doppler-Broadened Transition.- 4. Narrow Resonances of Two-Photon Transitions Without Doppler Broadening.- 5. Nonlinear Resonances on Coupled Doppler-Broadened Transitions.- 6. Narrow Nonlinear Resonances in Spectroscopy.- 7. Nonlinear Atomic Laser Spectroscopy.- 8. Nonlinear Molecular Laser Spectroscopy.- 9. Nonlinear Narrow Resonances in Quantum Electronics.- 10. Narrow Nonlinear Resonances in Experimental Physics.- 11. Conclusion.- Author Index.

Narrow-linewidth stimulated Brillouin fiber laser and applications

A stimulated Brillouin fiber ring laser with a spectral width of 2 kHz and an intrinsic linewidth of less than 30 Hz has been demonstrated. Applications of such a laser include laser linewidth narrowing, microwave frequency generation, high-rate amplitude modulation, and optical inertial rotation sensing.

Passive ring resonator laser gyroscope

A new method of measuring inertial rotation is presented. It is based on the use of a passive ring resonator as the rotation sensing element and an external laser for measuring the difference between the clockwise and counterclockwise lengths of the resonator. Preliminary performance data is included.

Passive fiber-optic ring resonator for rotation sensing.

A passive fiber-optic resonator technique for rotation sensing has been investigated. Preliminary data show a noise-equivalent rotation-rate sensitivity of 0.5 degrees /h (tau= 1 sec), which is an order of magnitude above the photonshot-noise limit. The major sources of error and ways of reducing such errors are discussed.

Stimulated Brillouin fiber-optic laser gyroscope

We achieved simultaneous bidirectional lasing in an all-fiber ring laser, using stimulated Brillouin scattering as the gain medium. The Brillouin lasing threshold was 60 microW for a He-Ne pump at 1.15 microm. The operation of this device as a ring-laser gyroscope was demonstrated.

Passive ring resonator method for sensitive inertial rotation measurements in geophysics and relativity

As part of a program to develop sensitive laser inertial rotation sensors, we have studied the performance of a passive-resonator technique using a 0.7-m x 0.7-m optical cavity. For an averaging time tau of 10 sec, the random drift was 1.1 x10(-2) deg/h, which was consistent with the shot-noise limit for the present setup. For a longer averaging time the random drift was 5.6 x 10(-3) deg/h (tau = 90 sec), showing a slight departure from the shot-noise limit. The problems encountered in the present apparatus, as well as those that are critical in the development of much larger esonators for geophysics and relativity applications, are discussed.

Closed-loop, low-noise fiber-optic rotation sensor.

A closed-loop, multiturn fiber-optic rotation sensor has been developed that exhibits low noise of the order of 0.1 masculine/h for an averaging time of 30 sec. This performance is consistent with the photon-noise limit for our setup. The length of the fiber is 200 m, and the coil diameter is 19 cm. Nonreciprocal phase modulation is accomplished with an electro-optic crystal driven at 470 kHz, and closed-loop operation is achieved by means of acousto-optic frequency shifters.

Study of Vortex Rings Using a Laser Doppler Velocimeter

filter resulting when the gyro drifts, accelerometer errors, and DME biases are neglected performs nearly optimally. Hence, alignment can be accomplished by using an eighth-order filter when using one VOR/DME, or a seventh-order filter when using two DMEs. The quantitative results presented here are, of course, dependent upon the validity of the error models assumed. In particular, the VOR/DME error model proposed here has not been as thoroughly checked experimentally as the inertial navigation system model.

Absolute distance measurements by variable wavelength interferometry.

This paper describes a laser interferometer which provides absolute distance measurements using tunable lasers. An active feedback loop system, in which the laser frequency is locked to the optical path length difference of the interferometer, is used to tune the laser wavelengths. If the two wavelengths are very close, electronic frequency counters can be used to measure the beat frequency between the two laser frequencies and thus to determine the optical path difference between the two legs of the interferometer.

Stabilized single-frequency stimulated Brillouin fiber ring laser.

The detailed behavior of the cw stimulated Brillouin fiber laser has been studied by using a narrow-linewidth cw pump argon laser at 5145 A and an 83-m fiber ring cavity. By stabilizing the fiber cavity, we achieved stable single-frequency Brillouin-laser output with a linewidth determined primarily by the 100-kHz modulation used in the feedback system. Lasing threshold for the 4.5-microm-core fiber used was observed at a pump power of 77 mW, and the maximum Brillouin output was 13 mW for a pump of 320 mW. The Brillouin gain medium was shown to exhibit homogeneouslike behavior.