Compact Squeezed Light Source Achieves -8 dB Improvement for Quantum Technologies
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Scientists are continually striving to develop more efficient quantum technologies, and a key component is reliable squeezed light sources. Shahar Monsa, Shmuel Sternklar, and Eliran Talker, all from Ariel University, have now demonstrated an ultra-compact and low-cost source of two-mode squeezed light at 795nm, achieved through four-wave mixing in hot rubidium vapour. This innovative design , utilising a modular architecture and minimal pump power , delivers up to -8dB of intensity-difference squeezing, offering a significant step towards deployable quantum-enhanced technologies for metrology, information processing, and communications. The narrowband character of the generated states also makes it particularly suitable for atomic-based applications and quantum networking, representing a versatile and portable platform for future advancements. This innovative system employs a streamlined architecture, a single fibre-coupled input, an electro-optic phase modulator paired with a single Fabry-Perot etalon for probe generation, and two free-space output modes for signal and conjugate fields, resulting in a significantly simplified and cost-effective design. Optimised for minimal pump power, the source delivers up to -8 dB of intensity-difference squeezing at an analysis frequency of 0.8MHz, utilising only 300mW of power.
The team achieved this breakthrough by focusing on a modular design that minimises complexity and optical loss, a key challenge in previous squeezed-light sources. Conventional methods often rely on multiple, costly components like Mach-Zehnder electro-optic modulators and numerous Fabry-Perot etalons to suppress unwanted modulation sidebands, increasing system size and power consumption. In contrast, this new approach utilises a single electro-optic phase modulator in conjunction with just one Fabry-Perot etalon to generate the frequency-shifted probe beam, dramatically reducing both optical loss and excess noise. Experiments show this simplified architecture yields a lower initial probe-beam noise compared to double-pass acousto-optic modulator and Mach-Zehnder electro-optic modulator schemes, enabling superior squeezing performance.
This research establishes a versatile and portable platform for generating low size, weight, and power (SWaP) squeezed light, opening doors to deployable quantum-enhanced technologies. The intrinsic narrowband character of the generated quantum states makes them ideal for precision measurements.
Rubidium Vapor Source of Narrowband Squeezed Light Scientists engineered a compact narrowband source of two-mode squeezed light at 795nm, leveraging four-wave mixing within hot 85Rb atomic vapor. The research team implemented a modular architecture featuring a single fiber-coupled input, an electro-optic phase modulator (EOPM), and a single Fabry-Perot (FP) etalon for probe generation, culminating in two free-space output modes for signal and conjugate fields. Optimized for minimal pump power, the system achieved -8 dB of intensity-difference squeezing at an analysis frequency of 0.8MHz, utilizing only 300mW of pump power, a significant advancement in efficient squeezed-light generation. This narrowband characteristic renders the source particularly suitable for atomic-based technologies and networking applications, including interfaces with atomic memories. To generate the frequency-detuned probe beam, the study pioneered an innovative approach employing an EOPM in conjunction with a single FP etalon, demonstrably outperforming traditional methods. Experiments compared this configuration against double-pass acousto-optic modulators (AOMs) and Mach-Zehnder electro-optic modulators (MZ-EOMs) with multiple FP etalons, revealing the lowest initial probe-beam noise with the EOPM/FP etalon combination. This improvement stems from the reduced number of optical components and the elimination of interferometric structures, minimizing optical loss and preserving quantum correlations. The optical power spectra generated using the EOPM and MZ-EOM were analyzed alongside the transmission peaks of a 15GHz free spectral range FP etalon, visually confirming the superior spectral purity of the EOPM-based approach. The electric field at the output of the EOPM is described by the equation E(t) = 1/2 E0eiω0t[J0(α) + 2J2(α)sin (2Ωt) + 2J3(α)sin (3Ωt) + ⋯ ], where E0 represents the input field amplitude, ω0 is the optical carrier frequency, Ω is the RF modulation frequency, and α is the modulation index. In contrast, the MZ-EOM output is expressed as E(t) = 1/2 E0eiω0t[4J1(α)sin (Ωt) + 4J3(α)sin (3Ωt) + ⋯ ]. The FP etalon efficiently suppresses unwanted frequency components, selectively transmitting the desired sideband due to the large spectral separation between adjacent modulation sidebands. Consequently, the team demonstrated that a single EOPM combined with a single FP etalon is sufficient to generate a clean probe beam frequency-shifted by 3.04GHz, avoiding the complexity and excess loss of interferometric modulators. Experiments utilized a double-Λ configuration in hot 85Rb vapor to generate narrowband two-mode squeezed light via four-wave mixing (FWM). A strong pump beam from an external-cavity diode laser (ECDL), amplified by a tapered amplifier, interacted with a probe beam frequency down-shifted by 3.04GHz using the EOPM and filtered by the FP etalon. This interaction resulted in the generation of correlated photon pairs, amplifying the probe field and creating a conjugate field, with the pump and probe frequencies tuned near the two-photon Raman resonance between the ground-state hyperfine level.
Scientists have demonstrated a compact narrowband source of two-mode squeezed light at 795nm, achieving up to -8 dB of intensity-difference squeezing at an analysis frequency of 0.8MHz. The breakthrough relies on four-wave mixing within hot 85Rb atomic vapor, implemented in a modular architecture with a single fiber-coupled input and free-space output modes for signal and conjugate fields. Optimized for low pump power, the system required only 300mW to reach this significant level of squeezing, representing a substantial advancement in quantum light source efficiency. Experiments revealed that the intrinsic narrowband character of the generated quantum states makes them ideal for high-precision measurements. Rubidium vapour delivers compact squeezed light source Scientists have developed a compact source of squeezed light at 795nm, utilising four-wave mixing within hot rubidium atomic vapour. This narrowband source achieves up to -8 dB of intensity-difference squeezing with a remarkably low pump power of 300mW, representing a significant advance in quantum photonics. The. The significance of this work lies in its potential to bridge the gap between laboratory experiments and real-world quantum technologies, particularly those requiring atomic interfaces. The narrowband nature of the squeezed states makes them ideally suited for applications in atomic physics. 👉 More information 🗞 Ultra Compact low cost two mode squeezed light source 🧠 ArXiv: https://arxiv.org/abs/2601.13939 Tags: