Observation of scalable sub-Poissonian-field lasing in a microlaser

Abstract

Sub-Poisson field with much reduced fluctuations in a cavity can boost quantum precision measurements via cavity-enhanced light-matter interactions. Strong coupling between an atom and a cavity mode has been utilized to generate highly sub-Poisson fields. However, a macroscopic number of optical intracavity photons with more than 3 dB variance reduction has not been possible. Here, we report sub-Poisson field lasing in a microlaser operating with hundreds of atoms with well-regulated atom-cavity coupling and interaction time. Its photon-number variance was 4 dB below the standard quantum limit while the intracavity mean photon number scalable up to 600. The highly sub-Poisson photon statistics were not deteriorated by simultaneous interaction of a large number of atoms. Our finding suggests an effective pathway to widely scalable near-Fock-state lasing at the macroscopic scale.

Frequency pushing enhanced by an exceptional point in an atom-cavity coupled system

“…The magnitude of frequency pushing is maximized at ∆ cp /2π ∼ ±1 MHz and the maximum frequency pushing is 41±7 kHz/per atom. This value is about 20 times larger than the maximum frequency pulling per atom observed in the cavity-QED microlaser [11] with N ∼ 250 and g/2π ≃ 190 kHz -well above the lasing threshold in the highly nonlinear region -generating intensity squeezed output [4]. The frequency pulling in the microlaser was influenced by many factors such as quantum jumps [24] and photon number stabilization [4], so a direct comparison with the frequency pushing here is difficult.…”

“…This value is about 20 times larger than the maximum frequency pulling per atom observed in the cavity-QED microlaser [11] with N ∼ 250 and g/2π ≃ 190 kHz -well above the lasing threshold in the highly nonlinear region -generating intensity squeezed output [4]. The frequency pulling in the microlaser was influenced by many factors such as quantum jumps [24] and photon number stabilization [4], so a direct comparison with the frequency pushing here is difficult. But one of the reasons why the present frequency shift is larger than those in the previous studies by an order of magnitude is that the frequency shift was maximized here by choosing the experimental conditions very close to the EP, near which we can still have a single peak lineshape while getting closer to the strong atom-cavity coupling regime.…”

“…The mean number N of atoms in the cavity are calibrated using the technique of n-vs-N curve of the cavity-QED microlaser [4,10,12,13]. In a nutshell, the unique characteristics in the lasing of the atom-cavity system are utilized.…”

“…Microscopic lasers utilizing the strong interactions between atoms and a cavity field can serve as a test ground for various quantum optical phenomena such as nonclassical photon statistics [1][2][3][4][5] and ultralow-threshold lasing [6][7][8]. In particular, an arrangement of atoms in a beam traversing a cavity in a short interaction time has advantages of preparing specific atomic states, fully inverted [9] or in a superposition state [10], and achieving steady-state operation while avoiding saturation effects.…”

Effects of Reservoir Input Fields on the Non-Classical Features of Quantum Beat Cascade Laser

“…The statistical properties of a light beam generated through a certain quantum optical system can be studied in the three regimes such as sub-Poissonian [32][33][34][35], super-Poissonian [36], and Poissonian ones. These photon statistical distributions are characterized by comparing the variance of the photon The light beams which possess the super-Poissonian photon statistics satisfy the mathematical inequality Δ𝑛 2 > 𝑛.…”