Subwavelength Raman Laser Driven by Quasi Bound State in the Continuum

Abstract Raman lasers are an actively developing field of nonlinear optics aiming to create efficient frequency converters and various optical sensors. Due to the growing importance of ultracompact chip‐scale technologies, there is a constant demand for optical device miniaturization; however, the development of a nanoscale Raman laser remains a challenging endeavor. In this work, a fully subwavelength Raman laser operating in visible range is proposed, based on a gallium phosphide nanocylinder resonator supporting a quasi‐bound state in the continuum (quasi‐BIC). The precise spectral matching of the nanoparticle high‐ Q modes is performed with the pump and detuned Raman emission wavelengths. The simulations demonstrate an experiment‐ready design of Raman nanolaser with a lasing threshold expected to be as low as . The proposed configuration represents the prototype of a low‐threshold Raman nanolaser with all dimensions smaller than the operational wavelength.