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This Letter proposes a new method to eliminate the quantum radiation pressure force noise in optomechanics at frequencies much smaller than the resonance frequency of the optomechanical mirror. With no radiation pressure force noise, the shot noise and thermal noise together determine the total noise in the system. The force sensitivity of the optomechanical cavity is improved beyond standard quantum limit at frequencies much smaller than the resonance frequency of the mechanical oscillator. Finally, optimum optomechanical cavity design parameters for attaining the best sensitivity are discussed.

This publisher’s note contains corrections to Opt. Lett. 45, 1256 (2020)OPLEDP0146-959210.1364/OL.385092.

We show that back-action noise in the momentum measurement of a damped forced oscillator can be suppressed because of damping. Using this principle, we propose a back-action suppressed interferometer, in which the signal is a function of momentum of atoms in a harmonic trap. We show that the quantum noise limited sensitivity of this interferometer can overcome the standard quantum limit of force sensing, even at frequencies much smaller than the eigen frequency of the harmonic trap.

We propose an interferometry technique, by using electromagnetically induced transparency phenomena, for measuring classical force. The classical force is estimated by measuring the phase at the output of the interferometer. The proposed measurement mechanism satisfies quantum non-demolition measurement conditions leading to back-action evasion. We further derive the sufficient condition under which the thermal noise in the interferometer is negligible. With no back-action noise and no thermal noise, the sensitivity of this technique is limited by shot noise only., Comment: 6 pages

Coherent quantum noise cancellation (CQNC) method is used to beat standard quantum limit (SQL) for improving the per-formance of quantum optomechanical gyroscopes. The protocol for realizing CQNC is achieved by constructing an effectivenegative mass mechanical oscillator, which is simulated by an ancillary cavity. This oscillator shows an antiresponse relativeto that of a real mechanical oscillator. Thus, the optomechanical back-action noise is counteracted or restrained, and we couldincrease our signal by increasing the coupling strength without increasing the noise.

In this article, we present an application of optomechanical cavity for the absolute rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of absolute rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.

In this article, we present an application of the optomechanical cavities for absolute rotation detection. Two optomechanical cavities, one in each arm, are placed in a Michelson interferometer. The interferometer is placed on a rotating table and is moved with a uniform velocity of with respect to the rotating table. The Coriolis force acting on the interferometer changes the length of the optomechanical cavity in one arm, while the length of the optomechanical cavity in the other arm is not changed. The phase shift corresponding to the change in the optomechanical cavity length is measured at the interferometer output to estimate the angular velocity of the absolute rotation. An analytic expression for the minimum detectable rotation rate corresponding to the standard quantum limit of measurable Coriolis force in the interferometer is derived. Squeezing technique is discussed to improve the rotation detection sensitivity by a factor of at 0 K temperature, where and are the damping rate and angular frequency of the mechanical oscillator. The temperature dependence of the rotation detection sensitivity is studied.

Stark splitting and quantum interference effects in the absorption spectrum of a probe field in coherently driven closed upper coupled three level atomic schemes ( and upper-cascade), which are created by a strong driving field are studied using the dressed state representation. In the dressed representation, the absorption due to the Stark splitting can be separated from the absorption due to the interference effects. We explicitly show the presence of both destructive and constructive interference in upper coupled three level atomic schemes. The interference in these atomic schemes is due to the coupling of the two dressed states by the same vacuum modes and the probe. We show that the dephasing rates can change the nature of the interference from constructive to destructive and vice versa, resulting in increased or decreased resonant absorption of the probe field.

In this article, we describe controlling the optomechanically induced transparency (OMIT) phenomena through rotation. An optomechanical cavity, which is coupled to a weak probe field and to a strong drive field, is placed along the diameter of a rotating table. When the table rotates, the centrifugal force due to rotation changes the length of the optomechanical cavity because of which the transparency window in OMIT disappears. We further point out that OMIT can be recovered by shifting both the drive and probe frequencies simultaneously. We derived an analytic parameter to estimate the minimum angular velocity that can effect OMIT for a given optomechanical cavity. In other words, we describe turning on and turning off OMIT by controlling the rotation rate.