Approaching quantum-limited cw anti-Stokes conversion through cavity-enhanced Raman-resonant four-wave mixing

Stimulated anti-Stokes Raman scattering resonantly enhanced in silica microspheres

“…In this Letter, we present cavity resonantenhanced SARS generation, multiorder SARS, and third-order nonlinear processes in silica WGMR at any dispersion value [15][16][17]. The cavity-enhanced SARS emission has a linewidth similar to that of SRS and the pump, and a high-quality mode [18].…”

“…In this Letter, we present cavity resonantenhanced SARS generation, multiorder SARS, and third-order nonlinear processes in silica WGMR at any dispersion value [15][16][17]. The cavity-enhanced SARS emission has a linewidth similar to that of SRS and the pump, and a high-quality mode [18].Microspheres can be easily fabricated directly on the tip of a standard telecom fiber. In order to obtain microspheres below the fiber diameter, we melt the end of a half-tapered fiber, obtained by heating and stretching the fiber itself until it breaks.…”

“…where P is the cavity build-up pump power, Ω∕2π is the frequency shift between the pump and the first Raman order, β 2 is the linear dispersion calculated as the variation of the free spectral range, γ is the nonlinearity coefficient and q 1 − α αχ 3 0.82 − i0.25, is a complex number that depends on the Raman susceptibility of silica and on the fractional contribution of the electronic susceptibility to the total nonlinear index [29,18]. This expression is valid for both regimes, normal and anomalous, as far as the linear dispersion Δk β 2 Ω 2 is large.…”

Phase-Matched Raman-Resonant Four-Wave Mixing in a Dispersion-Compensated High-Finesse Optical Cavity

“…Since Raman-resonant FWM and SRS contribute equally to a Raman process [10], it is expected cw-based FWM will be achieved with a high efficiency using the same approach as that used in the cw-based SRS. In fact, Roos et al suggested upconversion of a cw laser through an intracavity FWM process can be realized with an efficiency approaching the quantum limit (50%) [11]. Unfortunately, this theoretically predicted highly efficient cw-based FWM has not yet been achieved experimentally; this is because the efficiency of FWM in a high-finesse cavity is severely hindered by phase-mismatching among interactive fields (i.e., pump, Stokes, and anti-Stokes fields), arising from an inevitable frequency dependence of the refractive index of a Raman-active medium.…”

“…In the steady state limit, simple expressions can be obtained for intracavity powers of the pump and anti-Stokes fields by solving equations describing the coupling among monochromatic fields interacting with each other through Raman-active medium inside a dispersion-free optical cavity [11],…”