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Novel Approaches to Sensitivity Enhancement of Ring Laser Gyros

Marlan O. Scully, Sudhakar Prasad

Published Jun 1, 1990• 0 citations

Abstract

Abstract : A main theme of these papers are the role of quantum effects and determining how the sensitivity of optical sensor, such as the ring-laser gyro, can be improved. The correlated-spontaneous-emission laser (CEL) is a concept which permits reduction of quantum noise associated with the relative phase angle between two correlated laser transitions. The mechanism of quantum noise quenching in the original CEL device (quantum beat laser) has been explained using a geometrical approach, and a more rigorous analysis where amplitude noise is also included. Extensive studies on the CEL, including the effects of nonlinear saturation and atomic motion, was performed. The CEL concept has been found applicable to various types of devices, besides the quantum beat laser, for the purpose of quantum noise reduction. Using the CEL concept, we have developed the following four devices, which have the ability of quantum noise reduction, even squeezing.

Related papers

Correlated emission laser: concept, theory, and analysis

Marlan O. Scully, Muhammad Suhail Zubairy

As discussed in the last three chapters, the fundamental source of noise in a laser is spontaneous emission. A simple pictorial model for the origin of the laser linewidth envisions it as being due to the random phase diffusion process arising from the addition of spontaneously emitted photons with random phases to the laser field. In this chapter we show that the quantum noise leading to the laser linewidth can be suppressed below the standard, i.e., Schawlow–Townes limit by preparing the atomic systems in a coherent superposition of states as in the Hanle effect and quantum beat experiments discussed in Chapter 7. In such coherently prepared atoms the spontaneous emission is said to be correlated. Lasers operating via such a phase coherent atomic ensemble are known as correlated spontaneous emission lasers (CEL). An interesting aspect of the CEL is that it is possible to eliminate the spontaneous emission quantum noise in the relative linewidths by correlating the two spontaneous emission noise events. A number of schemes exist in which quantum noise quenching below the standard limit can be achieved. In two-mode schemes a correlation between the spontaneous emisson events in two different modes of the radiation field is established via atomic coherence so that the relative phase between them does not diffuse or fluctuate. In a Hanle laser and a quantum beat laser this is achieved by pumping the atoms coherently such that every spontaneously emitting atom contributes equally to the two modes of the radiation, leading to a reduction and even vanishing of the noise in the phase difference.

Cambridge University Press eBooks•Sep 4, 1997•0 citations

Correlated emission laser

Muhammad Suhail Zubairy, Shahid Qamar, Sadaf Sultana

We present a review of various schemes in which the quenching of spontaneous emission takes place in correlated emission laser (CEL). In particular we discuss Hanle laser, quantum beat laser, and a two-photon CEL. We also discuss noise-free amplification in a two-photon CEL.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 28, 1992•0 citations

Dynamically correlated spontaneous-emission laser: theory and comparison with experiment

János A. Bergou, Miguel Orszag

A higher-order correlated-emission laser (CEL) effect is found theoretically in a Doppler-broadened medium. A full quantum-mechanical account of the CEL in the nonlinear regime shows a large reduction in the beat-signal linewidth. This behavior is confirmed by a recent experiment.

Journal of the Optical Society of America B•Feb 1, 1988•5 citations

Quantum-noise quenching in the correlated spontaneous-emission laser as a multiplicative noise process. II. Rigorous analysis including amplitude noise

Wolfgang P. Schleich, Marlan O. Scully, H.-G. von Garßen

An analytical steady-state distribution for the phase difference \ensuremath{\psi} in a correlated spontaneous-emission laser (CEL) is derived based on the amplitude and phase equations of a CEL. This distribution is shown to be an excellent approximation to that obtained from a numerical simulation of the complete set of CEL equations. In particular, the effects of amplitude noise on CEL operation are considered and it is shown that fluctuations in the relative amplitude are also noise quenched.

Physical Review A•Apr 1, 1988•20 citations

Stability and instability of correlated emission lasers

Ann Cavin Strozewski, John C. Englund

The idea of using correlated emission to reduce spontaneous-emission noise in an active interferometer1 has recently been successfully implemented in a He–Ne Zeeman laser,2 an advance of particular significance for the development of high-sensitivity probes of metric gravity.1 Because the sensitivity of such probes is expected to increase with increasing laser power, we have begun assessing the degree to which instability imposes limitations on the operating levels of correlated-emission-laser (CEL) devices. In particular, we have found that the model of Bergou et al.3 of a homogeneously broadened, three-level CEL exhibits transitions to chaos that are very similar to the well-known Haken–Lorenz instability, and at quantitatively similar threshold powers. A CEL model more appropriate to Ref. 2 is also considered.

Annual Meeting Optical Society of America•Jan 1, 1992•0 citations

Generation of squeezing in a quantum beat laser

Muhammad Suhail Zubairy, Marlan O. Scully, M. Sargent

Recently Scully 1 proposed the concept of related spontaneous-emission laser with potential application to an improved active interferometer in mind. This laser is a two-mode laser in which the gain medium is prepared so as to eliminate the spontaneous emission fluctuations in the relative phase angle between the two laser modes. An important example of a correlated spontaneous emission laser is the quantum beat laser.2

•Apr 26, 1987•0 citations

Abstract : A main theme of these papers are the role of quantum effects and determining how the sensitivity of optical sensor, such as the ring-laser gyro, can be improved. The correlated-spontaneous-emission laser (CEL) is a concept which permits reduction of quantum noise associated with the relative phase angle between two correlated laser transitions. The mechanism of quantum noise quenching in the original CEL device (quantum beat laser) has been explained using a geometrical approach, and a more rigorous analysis where amplitude noise is also included. Extensive studies on the CEL, including the effects of nonlinear saturation and atomic motion, was performed. The CEL concept has been found applicable to various types of devices, besides the quantum beat laser, for the purpose of quantum noise reduction. Using the CEL concept, we have developed the following four devices, which have the ability of quantum noise reduction, even squeezing.

As discussed in the last three chapters, the fundamental source of noise in a laser is spontaneous emission. A simple pictorial model for the origin of the laser linewidth envisions it as being due to the random phase diffusion process arising from the addition of spontaneously emitted photons with random phases to the laser field. In this chapter we show that the quantum noise leading to the laser linewidth can be suppressed below the standard, i.e., Schawlow–Townes limit by preparing the atomic systems in a coherent superposition of states as in the Hanle effect and quantum beat experiments discussed in Chapter 7. In such coherently prepared atoms the spontaneous emission is said to be correlated. Lasers operating via such a phase coherent atomic ensemble are known as correlated spontaneous emission lasers (CEL). An interesting aspect of the CEL is that it is possible to eliminate the spontaneous emission quantum noise in the relative linewidths by correlating the two spontaneous emission noise events. A number of schemes exist in which quantum noise quenching below the standard limit can be achieved. In two-mode schemes a correlation between the spontaneous emisson events in two different modes of the radiation field is established via atomic coherence so that the relative phase between them does not diffuse or fluctuate. In a Hanle laser and a quantum beat laser this is achieved by pumping the atoms coherently such that every spontaneously emitting atom contributes equally to the two modes of the radiation, leading to a reduction and even vanishing of the noise in the phase difference.

An analytical steady-state distribution for the phase difference \ensuremath{\psi} in a correlated spontaneous-emission laser (CEL) is derived based on the amplitude and phase equations of a CEL. This distribution is shown to be an excellent approximation to that obtained from a numerical simulation of the complete set of CEL equations. In particular, the effects of amplitude noise on CEL operation are considered and it is shown that fluctuations in the relative amplitude are also noise quenched.

The idea of using correlated emission to reduce spontaneous-emission noise in an active interferometer1 has recently been successfully implemented in a He–Ne Zeeman laser,2 an advance of particular significance for the development of high-sensitivity probes of metric gravity.1 Because the sensitivity of such probes is expected to increase with increasing laser power, we have begun assessing the degree to which instability imposes limitations on the operating levels of correlated-emission-laser (CEL) devices. In particular, we have found that the model of Bergou et al.3 of a homogeneously broadened, three-level CEL exhibits transitions to chaos that are very similar to the well-known Haken–Lorenz instability, and at quantitatively similar threshold powers. A CEL model more appropriate to Ref. 2 is also considered.