Optical control of resonant light transmission for an atom-cavity system

2016

Phys. Rev. A

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The control of light transmission through a Fabry-Pérot cavity containing atoms is theoretically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the time dependent cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained in steady state limit. For an ensemble of atoms in the cavity mode, the response of the intra-cavity light intensity to the intersecting resonant beam is understood for stationary atoms (closed system) and non-static atoms (open system). The open system is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, with the thermal environment. The solutions to the model are used to qualitatively explain the observed steady state and transient behaviour of the light in the cavity mode, in Sharma et. al. [1]. The control behaviour with three-and two-level atomic systems is also studied, and the rich physics arising out of these systems, for closed and open atomic systems is discussed.

Section: Introductionmentioning

confidence: 54%

“…In this case the switching response of light through the cavity can be studied and connected to the experiments in Sharma et. al [1].…”

Section: Open System Of Atoms a Four Level Atomsmentioning

confidence: 98%

Section: B Two Level Atoms With Decay Lossmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…al. [1]. The application of this model to laser cooled atoms [19] or ions coupled to a cav- * Electronic address: rahuls@rri.res.in ity, is discussed.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical-bistability-enabled control of resonant light transmission for an atom-cavity system

Sawant

2016

Phys. Rev. A

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Lasing by driven atoms-cavity system in collective strong coupling regime

Sawant

2017

Sci Rep

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The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

All-optical switching in a continuously operated and strongly coupled atom-cavity system

Dutta

Applied Physics Letters

2017

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We experimentally demonstrate collective strong coupling, optical bi-stability (OB) and all-optical switching in a system consisting of ultracold 85 Rb atoms, trapped in a dark magneto-optical trap (DMOT), coupled to an optical Fabry-Perot cavity. The strong coupling is established by measuring the vacuum Rabi splitting (VRS) of a weak onaxis probe beam. The dependence of VRS on the probe beam power is measured and bi-stability in the cavity transmission is observed. We demonstrate control over the transmission of the probe beam through the atom-cavity system using a free-space off-axis control beam and show that the cavity transmission can be switched on and off in micro-second timescales using micro-Watt control powers. The utility of the system as a tool for sensitive, in-situ and rapid measurements is envisaged. [20,21] and, as we suggest here, in sensitive measurement of interactions. Essential requirements for many of these applications are atom-cavity strong coupling [9,11,12,14,21] and all-optical switching of the cavity output light [7,10,22,23]. Perhaps the most important goal is to engineer all-optical switches that are fast, yet can be operated with minimal power [22][23][24]. To this end, significant progress has been made in cavity QED systems consisting of a single atom strongly coupled to a high finesse cavity [21], which however require extremely precise system control. Here we study the relatively less explored complementary system consisting of an ensemble of trapped ultracold atoms collectively coupled to a low finesse cavity [9][10][11]. This results in a significant technical simplification and ease with which a low intensity, fast alloptical switch can be implemented.In this article, we show that atom-cavity collective strong coupling can be achieved on a non-cycling (i.e. open) transition in a continuously operated 85 Rb dark-spot magneto-optical trap (DMOT) [25,26]. The signature of collective strong coupling is vacuum Rabi splitting (VRS) which is observed using a weak on-axis probe beam. The dependence of VRS on the probe beam power is measured and optical bi-stability (OB) in the cavity transmission is observed. Control over the nature of OB curve using a freespace off-axis control beam is demonstrated. We finally show that the cavity transmission can be switched on and off in micro-second timescales using micro-Watt control powers. Remarkably, a DMOT of ultracold atoms coupled to a cavity can be operated analogous to both strongly coupled atom-cavity systems as well as weakly coupled vapor cell based cavity systems, and retain advantages of the respective systems.The details of the overall experimental apparatus which consists of an atom trap and an ion trap at the mode center of a low finesse optical cavity has been described elsewhere [11,27]. A schematic representation of parts relevant for the present experiments is shown in Fig. 1(a). The 85 Rb DMOT is loaded from a Rb dispenser source. The DMOT is formed by three mutually orthogonal pairs of counter-propagating cooling beams ...