Thermal lens effect with light’s orbital angular momentum

Abstract

Thermal lens effect has been well developed and exploited for decades by using the Gaussian intensity distribution of a laser beam. In this paper, a new thermal lens effect by using a laser beam with Orbital Angular Momentum (OAM) is proposed. We find that the dynamic process for the formation of the OAM-thermal lens has reda rapid change towards the evolution direction at the beginning but then slowly approaches to a steady state for a while. This phenomenon is significantly different from the traditional Gaussian-thermal lens, thus it may be used to improve the sensitivity of the absorption spectrum for the chemical and biomedical analysis. Besides, theoretically and experimentally, the factors affecting the steady state of the OAM-thermal lens are also studied, hoping these may provide a useful reference for the research community. We also find a potential slow thermal-optical gate that can control of light passing through or blocking by changing the OAM of the heating beam. Our work opens the door which utilizes the structured light beam to study the thermal-optical effect, and more interesting phenomena remain to be explored.