Second-order Interference Pattern Research Articles

Theoretical analysis of a polarized two-photon Michelson interferometer with broadband chaotic light

Two-photon interference of broadband chaotic light in a Michelson interferometer is theoretically and numerically studied with a two-photon-absorption detector when polarizations are taken into account. Under the frame of quantum optics, the theoretical analysis is based on two-photon interference and Feynman path integral theory. A two-photon coherence matrix is introduced to calculate the second-order interference pattern. Our research shows that polarization is another dimension, as well as time and space, to tune the second-order interference pattern in the two-photon interference process. Polarizations can act as switches to manipulate the interference process and may open the door to some new experimental schemes. The quantum optical vector model is also helpful to understand the physics of second-order interference when the light source is quantum.

Second-order interference of two independent photons with different spectra**Project supported by the Key Research and Development Project of Shaanxi Province, China (Grant No. 2019ZDLGY09-08), the Open Fund of MOE Key Laboratory of Weak-Light Nonlinear Photonics, China (Grant No. OS19-2), and the Fundamental Research Funds for the Central Universities, China.

The second-order interference of two independent photons with different spectra in a Shih–Alley/Hong–Ou–Mandel interferometer is studied in Feynman’s path integral theory. There is a second-order interference pattern for photons with different spectra if the photons are indistinguishable for the employed detection system. The conditions to observe the second-order temporal beating with photons of different spectra are analyzed. The influence of the response time of the detection system on the observed second-order interference pattern is also discussed. It is a direct result of that measurement in quantum mechanics is dependent on the employed measuring apparatus. The results are helpful to understand the physics of two-photon interference in different schemes.

Second-order temporal interference of two independent light beams at an asymmetrical beam splitter**Project supported by the National Natural Science Foundation of China (Grant No. 11404255), the Doctor Foundation of Education Ministry of China (Grant No. 20130201120013), the Programme of Introducing Talents of Discipline to Universities, China (Grant No. B14040), and the Fundamental Research Funds for the Central Universities, China.

The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman’s path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds the classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when an asymmetrical beam splitter is employed.

Studying the optical second-order interference pattern formation process with classical light in the photon counting regime.

The formation process of the second-order interference pattern is studied experimentally in the photon counting regime by superposing two independent single-mode continuous-wave lasers. Two-photon interference based on the superposition principle in Feynman's path integral theory is employed to interpret the experimental results. The second-order interference pattern of classical light can be formulated when, with high probability, there are only two photons in the interferometer at one time. The studies are helpful in understanding the second-order interference of classical light in the language of photons. The method and conclusions can be generalized to the third- and higher-order interference of light and interference of massive particles.

The second-order interference of two independent single-mode He–Ne lasers

The second-order spatial and temporal interference patterns with two independent single-mode continuous-wave He–Ne lasers are observed when these two lasers are incident to two adjacent input ports of a 1:1 non-polarizing beam splitter, respectively. Two-photon interference based on the superposition principle in Feynman's path integral theory is employed to interpret the experimental results. The conditions to observe the second-order interference pattern with two independent single-mode continuous-wave lasers are discussed. It is concluded that frequency stability is important to observe the second-order interference pattern with two independent light beams.

The second-order interference between laser and thermal light

Anticorrelation is observed when laser and pseudothermal light beams are incident to the two input ports of a Hong-Ou-Mandel interferometer, respectively. The spatial second-order interference pattern of laser and pseudothermal light beams is reported. A temporal Hong-Ou-Mandel dip is observed when these two detectors are in symmetrical positions. The experimental results can be interpreted by the two-photon interference theory.

Strong-Field Spatial Interference in a Tailored Electromagnetic Bath

Light scattered by a regular structure of atoms can exhibit interference signatures, similar to the classical double-slit. These first-order interferences, however, vanish for strong light intensities, restricting potential applications. Here, we show how to overcome these limitations to quantum interference in strong fields. First, we recover the first-order interference in strong fields via a tailored electromagnetic bath with a suitable frequency dependence. At strong driving, the optical properties for different spectral bands are distinct, thus extending the set of observables. We further show that for a two-photon detector as, e.g., in lithography, increasing the field intensity leads to twice the spatial resolution of the second-order interference pattern compared to the weak-field case.