Measurement of Highly Nonlocal Nonlinear Responses via Circular Airy Beams

Structured light is extensively employed in optical measurements due to its exotic behaviors in light-matter interactions. Notably, it exhibits exceptional capability in detecting the nonlinear response of optical media. Nevertheless, current detections enabled by structured light are limited to local nonlinearities. Here, an approach for measuring highly nonlocal nonlinear responses via a circular Airy beam is demonstrated. Under the action of a highly nonlocal nonlinearity, the profile of the beam is reshaped to a ring pattern whose size is linearly increased with the injected optical power. The slope of the linear relation reveals the nonlocal response, as proved by the theory. Experimentally, the method is verified by testing a typical medium having a highly nonlocal nonlinearity. The findings may trigger more studies on the measurement of optical nonlinearities via structured light.