We found the full information of the output multimode state in the Spontaneous Parametric Down–Conversion, in the lossy 1D waveguide, still manifesting quantum behavior. We refer the results to the Raman scattering in atomic media.
We study the process of multimode spontaneous parametric down–conversion (SPDC) in a lossy, one-dimensional waveguide. We propose a description using first-order correlation functions (CF) in the fluorescence fields, as a very fruitful and easy approach providing us with complete information about the final multimode state. We formulate the equation of the evolution of the multimode CF along the crystal using four characteristic length scales. We solve it analytically in the one mode case and numerically in the multimode case. We capture simultaneous effects of three-wave mixing with ultrashort pump, linear propagation and attenuation, and we are able to divide the evolution into three stages and predict it qualitatively. We find that losses do not destroy the quantum properties of SPDC but stabilize the final state.
Integrated optical circuits enable stable and scalable realization of quantum logic devices, which can form a basis for the mass production of photonic chips for quantum communications and computations. An important challenge is the integration of single-photon sources, which should provide on-chip generation and preparation of quantum photon states. Spontaneous parametric down-conversion (SPDC) provides an attractive solution for experimental generation of correlated and entangled photon pairs [1,2]. However, internal losses in the waveguides may still be present, affecting nontrivially the emerging photon state [3].
Spontaneous parametric down-conversion (SPDC) in media with no inversion center and the use of this phenomenon in the spectroscopy of natural oscillation states of a crystal lattice (i.e., optical phonons) are retrospectively described. We think that the SPDC spectroscopy method is estimated inappropriately and hope to again attract the attention of readers to one of the most interesting quantum phenomena of nonlinear optics that has no classical analog. The capabilities of SPDC spectroscopy will certainly be used in both fundamental science and technology of new materials.
We develop a fully quantum-mechanical approach for the description of spontaneous parametric down-conversion in waveguides. Our method allows us to write an expression for the quantum state easily and directly, even when multiple photon pairs are generated in the process. The role of material dispersion in the normalization of the modes of the system, usually neglected, is properly treated here. The example of an AlyOx/Al0.5Ga0.5As ridge waveguide is discussed to illustrate the application of the formalism.
We study the process of multimode spontaneous parametric down–conversion (SPDC) in a lossy, one-dimensional waveguide. We propose a description using first-order correlation functions (CF) in the fluorescence fields, as a very fruitful and easy approach providing us with complete information about the final multimode state. We formulate the equation of the evolution of the multimode CF along the crystal using four characteristic length scales. We solve it analytically in the one mode case and numerically in the multimode case. We capture simultaneous effects of three-wave mixing with ultrashort pump, linear propagation and attenuation, and we are able to divide the evolution into three stages and predict it qualitatively. We find that losses do not destroy the quantum properties of SPDC but stabilize the final state.