Quantum correlations across two octaves from combined up- and down-conversion

Abstract

We propose and analyze a cascaded optical parametric system which involves three interacting modes across two octaves of frequency difference. Our system, combining degenerate optical parametric oscillation (OPO) with second harmonic generation (SHG), promises to be a useful source of squeezed and entangled light at three differing frequencies. We show how changes in damping rates and the ratio of the two concurrent nonlinearities affect the quantum correlations in the output fields. We analyze the threshold behavior, showing how the normal OPO threshold is changed by the addition of the SHG interactions. We also find that the inclusion of the OPO interaction removes the self-pulsing behavior found in normal SHG. Finally, we show how the Einstein-PodolskyRosen correlations can be controlled by the injection of a coherent seed field at the lower frequency.

Two-Color Quantum Correlation between Down-Conversion Beams at 1.5 and 3.3 μm from a Singly Resonant Optical Parametric Oscillator

“…Continuous wave (CW) light beams that exhibit nonclassical statistics and quantum correlation are of interest for fundamental tests of quantum physics, and potential applications including high-precision measurements beyond the shot-noise level (SNL) and quantum information such as quantum key distribution and quantum teleportation [1][2][3][4][5][6]. The common method to generate quantum correlated light beams is using an optical parametric oscillator (OPO) with a nonlinear crystal in the cavity [7][8][9][10][11][12]. In 1987, the quantum correlated twin beams generated by OPO was firstly proposed [7], and the intensity difference fluctuations of the twin beams below the corresponding SNL was experimentally observed [8].…”

“…In 1987, the quantum correlated twin beams generated by OPO was firstly proposed [7], and the intensity difference fluctuations of the twin beams below the corresponding SNL was experimentally observed [8]. Furthermore, with the help of high-quality nonlinear crystals, high-level quantum correlations between down-conversion beams from OPO could be obtained [9][10][11][12]. In these studies, the frequencies of quantum-correlated twin beams (the signal and idler beams) were degenerate, and polarizations of that were orthogonal.…”

Steady states, squeezing, and entanglement in intracavity triplet down conversion

“…Intracavity pair down conversion, whereby pump photons are parametrically converted into pairs of photons inside a χ (2) nonlinear medium, is a well studied process due to its many applications, particularly for allowing widely-tunable light sources-even as wide as two octaves [1][2][3][4]-and squeezed light generation [5][6][7]. The degenerate case, 2ω → ω + ω, where the generated photons are of the same polarization, is notable for being the leader in squeezed light generation, with a record of more than 15 dB squeezing [8].…”

Squeezing over Two Octaves of Frequency Difference with Second Harmonic Coupling

“…Squeezing occurred at both the fundamental and second harmonic frequencies of the field modes, which was the primary feature of the process throughout an octave. For applications involving several wavelengths, such as telecommunications [6], squeezed light at higher frequency ranges may be useful. Therefore, developing an interaction scheme that enables higher harmonic generation is necessary to achieve squeezing at higher frequency ranges.…”

“…Therefore, developing an interaction scheme that enables higher harmonic generation is necessary to achieve squeezing at higher frequency ranges. Implementing light-matter interaction over two octaves from combined up and down conversion [6], direct third harmonic [7], and cascaded harmonic generation [8,9] are a few examples of how this can be done, all of which have interesting quantum correlations that are particularly relevant for quantum state engineering. While these studies focused on the quantum correlation that occurs in a system with a single nonlinear media for each octave, enhancement of squeezing over two octaves of frequency difference is possible by including more interactive media into the cavity of two octaves [10].…”