Enhanced frequency up-conversion based on four-wave mixing assisted by a Bessel-Gaussian beam in 85Rb atoms

Abstract

We present an enhanced frequency up-conversion based on four-wave mixing process assisted by a Bessel-Gaussian beam in a 5S1/2 − 5P3/2 − 5D5/2 − 6P3/2 − 5S1/2 diamond-type atomic system of 85Rb. The 420 nm coherent blue light (CBL) is generated and an enhanced conversion efficiency of approximately two times is realized using the Bessel-Gaussian beam as a pump laser compared with that of the Gaussian beam. The non-diffracting property of the Bessel-Gaussian beam, which overcomes the diffractive spread and retains a high intensity over a long distance, leads to the high conversion efficiency. The influence of different pump powers on the enhancement effect is investigated in detail. Furthermore, the CBL generated by the Bessel-Gaussian beam is immune to obstacles owing to the self-healing ability, which extends its application scenarios. The enhanced frequency up-conversion based on structured light is beneficial to the applications of the blue-violet light source, and holds tremendous promises for extending the existing nonlinear toolkit.