We model the propagation of squeezed light through a dielectric medium. Frequency-dependent absorption reduces the level of squeezing and may decrease the squeezing bandwidth. Dispersion dephases the squeezing at different frequencies within the spectrum.
The behavior of short quantum light pulses propagating in dispersive and absorbing linear ground-state dielectrics is studied, with special emphasis on squeezed pulses. The analysis is based on normally ordered correlation functions of the electric-field strength, which are related to quantities at the entrance plane, on using quantum Langevin equations. Using nonmonochromatic-mode expansion and restricting attention to a single-mode pulse in a squeezed state, the influence on squeezing of the pulse propagation in the medium is discussed in both the time and frequency domains, and it is shown that the noise reduction observable in homodyne detection sensitively depends on the phase control used. Effects, such as squeezing enhancement associated with pulse compression and the destructive influence of the spectral shift caused by absorption, are demonstrated. The numerical results are supplemented by analytical estimations derived for narrow-bandwidth Gaussian pulses. \textcopyright{} 1996 The American Physical Society.
Squeezed light, in which the quantum noise in one amplitude component is reduced below the vacuum level, has been generated using parametric processes. The starting point described here is the nonlinear Schrodinger equation which models light propagating through optical fibers. When such a dispersive nonlinear medium with a third-order susceptibility is pumped with an optical beam, squeezing can result. It is found that the degree of squeezing oscillates as a function of fiber length in the normal dispersion regime, whereas in the anomalous dispersion regime, it grows exponentially with fiber length. Examination of squeezing near the fiber’s zero dispersion wavelength shows that odd-order dispersive terms have no effect on squeezing. However, small values of higher-order even terms have significant effects on squeezing. In practice, high-frequency components of the squeezing spectrum are difficult to obtain. However, it is shown that a cross-correlation technique may be used to explore the frequency dependence of the squeezing spectrum.
The problem of quantizing the radiation field inside a nonlinear dielectric is studied. Based on the quantization of radiation in a linear dielectric which includes absorption and dispersion, we extend the theory in order to treat also nonlinear optical processes. We derive propagation equations in space and time for the quantized radiation field including the effects of linear absorption and dispersion as well as nonlinear optical effects. As a special case we derive the propagation equation of a narrow-frequency band light pulse in a Kerr medium.