Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching light source in photonic crystal fiber with g2(0) reaching 5.86*104 and g5(0) up to 2.72*108, through measuring its photon number probability distributions. under giant g2(0) values, the super-bunching light source presents upturned-tail photon distributions and ubiquitous extreme multi-photon events, where 31 photons from a single light pulse at a mean of 1.99*10-4 photons per pulse have been determined. The probability of this extreme event has been enhanced by 10139 folds compared to a coherent laser with Poissonian distribution. By varying the power of the pumping laser, both photon number distributions and corresponding high-order correlations of this light source can be substantially tailored from Poissonian to super-bunching distributions. These phenomena are attributed to the synchronized nonlinear interactions in photonic crystal fibers pumping by bright squeezed light, and the theoretical simulations agree well with the experimental results. Our research showcases the ability to achieve non-classical light sources with giant high-order correlations and extreme multi-photon events, paving the way for high-order correlation imaging, extreme nonlinear optical effects, quantum information processing, and exploring light-matter interactions with multi-photon physics.
Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching light source in photonic crystal fiber with g2(0) reaching 5.86104 and g5(0) up to 2.72108, through measuring its photon number probability distributions. under giant g2(0) values, the super-bunching light source presents upturned-tail photon distributions and ubiquitous extreme multi-photon events, where 31 photons from a single light pulse at a mean of 1.99*10-4 photons per pulse have been determined. The probability of this extreme event has been enhanced by 10139 folds compared to a coherent laser with Poissonian distribution. By varying the power of the pumping laser, both photon number distributions and corresponding high-order correlations of this light source can be substantially tailored from Poissonian to super-bunching distributions. These phenomena are attributed to the synchronized nonlinear interactions in photonic crystal fibers pumping by bright squeezed light, and the theoretical simulations agree well with the experimental results. Our research showcases the ability to achieve non-classical light sources with giant high-order correlations and extreme multi-photon events, paving the way for high-order correlation imaging, extreme nonlinear optical effects, quantum information processing, and exploring light-matter interactions with multi-photon physics.
Abstract Photon superbunching, with second-order coherence far beyond the Gaussian thermal limit, is a valuable resource for quantum optics and correlation-based imaging. However, existing sources often rely on fragile platforms, inefficient nonlinear conversion, or mechanically complex architectures. Here, we demonstrate the first highly stable, fully fiber-integrated superbunched random fiber laser that provides a broadly tunable source of giant photon bunching. We establish a cooperative linear–nonlinear mechanism in which Rayleigh-scattering-mediated diffusion provides distributed random feedback, while cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing amplify and redistribute stochastic intensity fluctuations across a spectral comb. This enables continuous tuning of g (2) (0) from approximately 1 to 28 via tailored modulation of linear diffusion strength and nonlinear coupling magnitude. Moreover, by combining photon-correlation measurements with Parisi-overlap analysis, we reveal an inverse correlation between disorder-induced photonic phase evolution and microscopic photon bunching, bridging macroscopic disordered-cavity dynamics and high-order photon statistics. Furthermore, we demonstrate that strongly superbunched light enables temporal ghost imaging with comparable reconstruction fidelity while requiring more than an order-of-magnitude fewer realizations than weakly bunched light. Together, these results establish a fiber-integrated route to engineering giant photon superbunching and high-order light statistics for correlation-based photonic technologies.
Attosecond spectroscopy comprises several techniques to probe matter through electrons and photons. One frontier of attosecond methods is to reveal complex phenomena arising from quantum-mechanical correlations in the matter system, in the photon fields and among them. Recent theories have laid the groundwork for understanding how quantum-optical properties affect high-field photonics, such as strong-field ionization and acceleration of electrons in quantum-optical fields, and how entanglement between the field modes arises during the interaction. Here we demonstrate a new experimental approach that transduces some properties of a quantum-optical state through a strong-field nonlinearity. We perturb high-harmonic emission from a semiconductor with a bright squeezed vacuum field resulting in the emission of sidebands of the high-harmonics with super-Poissonian statistics, indicating that the emitted photons are bunched. Our results suggest that perturbing strong-field dynamics with quantum-optical states is a viable way to coherently control the generation of these states at short wavelengths, such as extreme ultraviolet or soft X-rays. Quantum correlations will be instrumental to advance attosecond spectroscopy and imaging beyond the classical limits.
Photon superbunching, distinguished by second-order coherence values far exceeding the Gaussian thermal limit, represents a highly desirable resource for quantum optics and correlation-based imaging technologies. However, existing approaches typically rely on fragile experimental platforms, inefficient nonlinear conversion processes, or mechanically complex optical architectures. Here, we demonstrate a fully fiber-integrated superbunched random fiber laser (SRFL) in which intrinsic Rayleigh scattering cooperatively interacts with cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing to tailor extreme photon statistics. The SRFL generates a multi-wavelength comb, in which individual spectral components exhibit widely tunable photon bunching, with the second-order coherence g(2)(0) continuously controlled from ~1 to ~26 by tuning the pump power, spectral order and diffusion length. Moreover, we establish a direct correlation between photonic phase transitions (quantified by the Parisi overlap order parameter) and the emergence of superbunching, thereby bridging macroscopic disorder physics and microscopic photon statistics. Finally, we employ the superbunched emission for temporal ghost imaging, realizing high-fidelity temporal object reconstruction with a substantial reduction in required ensemble averaging. These findings validate random fiber lasers as a robust, scalable, and integrated platform for generating extreme photon statistics and unlock new avenues for correlation-enhanced photonic sensing and quantum optics investigations in complex photonic systems.
Correlation imaging based on entangled light sources offers potential benefits over classical single-photon imaging (SPI) in noisy environments, but also faces challenges such as low brightness, long integration times, and difficulty imaging biological organisms. Here, we propose noise-resistant biologically correlated biphoton imaging (CPI) based on a super-bunching light source, addressing the challenge of severe signal-to-noise ratio degradation in conventional SPI schemes. Our CPI, based on a super-bunching light source with high brightness, broadband spectrum (400–1100 nm), and strong quantum correlation (g 2 (0) ∼ 250), delivers high-performance, noise-resistant operation by extracting correlated photon pairs between the reference and signal paths. Experimental results show that under extreme noise conditions (noise-to-signal ratio up to 600), the structural profile in conventional SPI is entirely obscured by noise. In contrast, CPI still clearly resolves the target structure. Quantitative analysis further reveals that, as noise intensity increases, the imaging visibility of CPI can be enhanced by more than two orders of magnitude compared to SPI schemes. This study confirms the exceptional robustness and practical utility of super-bunching light-based correlated imaging in high-noise environments, offering an effective technical approach for high-quality biological observation in complex optical conditions.
The effect of the quantum properties of light on nonlinear processes has been well studied theoretically. It has been shown that the efficiency of n-photon nonlinear processes in many cases scales as the normalized n-th order correlation function. For light with high intensity correlation function, the efficiency of the n-th harmonic generation will be considerably higher than for coherent light. The experimental observation of this effect remained difficult until recently, because of the absence of bright sources with strong and fast intensity fluctuations. For the experimental demonstration of statistical effects in optical harmonic generation we use as a pump the radiation of high-gain parametric down conversion. Such light shows quantum properties (e.g. quadrature or two-mode squeezing) and has large number of photons in one mode. The normalized n-th order correlation function for this light is (2n - 1)!!, which makes it more attractive for nonlinear processes than both coherent and thermal light. For the generation of optical harmonics we used broadband parametric down conversion around frequency-degeneracy (1600 nm) produced in 1cm BBO crystal from Ti:Sapphire laser (800 nm, 1.6ps, 5kHz, 3W mean intensity). Due to spectral filtering and post-selection technique we could vary the statistics of light from coherent to super-bunched, which allowed us to demonstrate the efficiency enhancement for second-, third-, and fourth-harmonic generation. The obtained experimental results show a good agreement with the theory.
Abstract Accurate detection and identification of space-based faint targets under strong background is a pressing challenge for all‑weather deep space exploration. However, active deep space detection is often hampered by the disturbances of intense stellar stray light and multi-source heterogeneous noise, making it difficult to achieve noise‑blind source separation and accurate identification of weak target signals under extremely low signal-to-noise ratio. To address these challenges, we develop a random dynamic mask modulation scheme to enhance higher-order coherence, unveiling power-law photon number distributions and super-bunching correlations that enable higher-order photon correlation imaging with a single-photon detector array (SPDA). The imaging scheme decouples the target signal from multi-source disturbances including coherent, thermal, and super-bunching light, as well as multiple background noises such as shot noise, environmental stray light, and dark counts. Here, we experimentally demonstrate a super-bunching light with a fiftieth-order photon correlation of 1.45×10 72 at a mean photon number , achieving a 10 42 enhancement in the high-to-second-order correlation ratio. The super-bunching light source enables continuously tunable output intensity from ultra‑weak to extremely bright, overcoming the limitation of conventional sources that produce only ultra‑weak photon numbers. Strikingly, we observe the ratio R n >2 of the multiphoton probability between the signal power-law light and a noise coherent laser reaching 5.29×10 269 at for 281 photons. The contrast in higher-order photon correlation imaging reaches 0.99, increasing by 0.26 over the second-order case. At an imaging exposure time of 5 µs and a mean photon number , we achieve 512×512‑pixel SPDA imaging with a dynamic range of 252.93 dB despite simultaneous photon‑starved signal and intense background. Our noise‑blind scheme establishes ultra‑wide dynamic range, high‑speed, sub-megapixel single‑photon imaging under multi‑source noise and intense optical disturbances, opening new routes for space surveillance and quantum‑enhanced detection.