Two-mode difference-squeezing in CARS and CAHRS processes

Qun Zhang

Dilip Kumar Giri, Partha Sarathi Gupta

The non-classical effects of squeezing of light in coherent anti-Stokes Raman scattering (CARS) and coherent anti-Stokes hyper-Raman scattering (CAHRS) are investigated under the short-time approximation based on a fully quantum mechanical approach. In an idealized model CARS, the interaction is looked upon as a process involving absorption of a pump photon and emission of a Stokes photon, which is followed by absorption of a pump photon and subsequently emission of an anti-Stokes photon at a different frequency, whereas CAHRS is looked upon as a process involving absorption of two pump photons and emission of a Stokes photon, which is followed by absorption of two more pump photons and subsequent emission of an anti-Stokes photon at a different frequency. The coupled Heisenberg equations of motion involving real and imaginary parts of the quadrature operators are established. It is shown that squeezing in the Stokes and anti-Stokes mode in CARS is found to be dependent on amplitude-squared squeezing of the initial pump field while, in CAHRS, it is dependent on the fourth-order amplitude squeezing of the initial pump field. Higher-order squeezing can be converted to linear squeezing through these processes. It is also shown that squeezing is greater in CAHRS than the corresponding squeezing in CARS.

P. D. Drummond, Z. Ficek

Suhail Zubairy

Dilip Kumar Giri, Partha Sarathi Gupta, M. K. Mahan +1 more

Priyanka Kapil

This paper investigates the generation of Signal to Noise Ratio (SNR) in Coherent anti-Stokes Raman Scattering (CARS) process in various orders of field amplitude for a squeezed light. Furthermore, we show that the signal-to-noise ratio is enhanced at lower orders of the field amplitude and scales proportionally with the number of pump photons present in the nonlinear medium before the interaction.