Intracavity absorption line shape and the super-regen model

Viktor S. Burakov, P. Ya. Misakov, P. A. Naumenkov +2 more

W. Brunner, Henryk Paul

Erik A. Bloemsma, Jasper Knoester

Based on the generating function formalism, we investigate broadband photon statistics of emission for single dimers and trimers driven by a continuous monochromatic laser field. In particular, we study the first and second moments of the emission statistics, which are the fluorescence excitation line shape and Mandel's Q parameter. Numerical results for this line shape and the Q parameter versus laser frequency in the limit of long measurement times are obtained. We show that in the limit of small Rabi frequencies and laser frequencies close to resonance with one of the one-exciton states, the results for the line shape and Q parameter reduce to those of a two-level monomer. For laser frequencies halfway the transition frequency of a two-exciton state, the photon bunching effect associated with two-photon absorption processes is observed. This super-Poissonian peak is characterized in terms of the ratio between the two-photon absorption line shape and the underlying two-level monomer line shapes. Upon increasing the Rabi frequency, the Q parameter shows a transition from super- to sub- to super-Poissonian statistics. Results of broadband photon statistics are also discussed in the context of a transition (frequency) resolved photon detection scheme, photon tracking, which provides a greater insight in the different physical processes that occur in the multi-level systems.

Andrew D. Ludlow, H. Mark Nelson, Scott Bergeson

We report measurements of thermal self-locking of a Fabry–Perot cavity containing a potassium niobate (KNbO3) crystal. We develop a method to determine linear and nonlinear optical absorption coefficients in intracavity crystals by detailed analysis of the transmission line shapes. These line shapes are typical of optical bistability in thermally loaded cavities. For our crystal we determine the one-photon absorption coefficient at 846 nm to be α=(0.0034±0.0022) m-1, the two-photon absorption coefficient at 846 nm to be β=(3.2±0.5)×10-11 m/W, and the one-photon absorption coefficient at 423 nm to be (13±2) m-1. We also address the issue of blue-light-induced infrared-absorption and determine a coefficient for this excited-state absorption process. Our method is particularly well suited to bulk absorption measurements where absorption is small compared with scattering. We also report new measurements of the temperature dependence of the index of refraction at 846 nm and compare with values in the literature.

W. Brunner, Henryk Paul

P. Malara, Carlo Edoardo Campanella, A. Giorgini +3 more

In this work, we analyze the possibility of exploiting the recently demonstrated super-resonant intracavity coherent absorption effect for quantitative sensing applications. The method relies on a system of two nested resonators (ring and Fabry-Perot) which allows to increase the radiation-matter interaction pathlength by a factor proportional to the product of the two resonator’s individual finesse coefficients. In this way, it is possible to dramatically increase the interaction of intracavity radiation with a weakly absorbing sample without need of an ultra-high finesse optical cavity. Here, we propose a measurement strategy that allows to exploit the super-resonant enhancement provided by the nested-resonators system and cancel out the noise connected with the radiation source at the same time, and compare it to a conventional cavity-enhanced absorption measurement.