Investigation of diffraction grating in photothermal cavity

Abstract

The photothermal effects in an optical cavity driven by a strong control field and a weak probe field have recently been shown to generate an induced transparency phenomenon (Ma et al., 2020). This phenomenon, referred to as photothermally induced transparency (PTIT), arises from the nonlinear behavior of an optical resonator caused by optical heating of the its mirrors. In this study, we investigate the manipulation of PTIT by substituting the strong coupling field in the PTIT scheme with a spatially periodic standing wave (SW) coupling field, resulting in the diffraction of the weak probe field into high-order diffractions. The resulting structure, termed the photothermally induced grating (PTIG), can be effectively controlled by adjusting various system parameters, including the coupling strength, effective detuning, interaction length, and photothermal coefficient. By carefully optimizing the coupling strength, we demonstrate that a significant portion of the probe field energy can be efficiently transferred to the third-order diffraction grating. The introduction of a spatially periodic standing wave coupling field opens up new possibilities for designing and manipulating photothermally induced gratings with enhanced functionalities.