Suppressing cavity resonances via intra-cavity mode conversion with a holographic phase mask

We demonstrate a resonance-free spectral response in a Fabry-Pérot cavity by incorporating a single intra-cavity holographic phase mask that incrementally increases the azimuthal index of the circulating light. This structured mode evolution transforms an input Gaussian beam into a superposition of orthogonal Laguerre-Gaussian (LG) modes with increasing orbital angular momentum, effectively suppressing the constructive interference required for resonance. The LG basis enables a unique OAM ladder-up behavior absent in non 2dimensional modes, which facilitates modal divergence without coupling back to lower orders. As a result, the output spectrum remains broadband and stable even under significant cavity length variations. This work introduces a novel mechanism for manipulating complex light within resonant systems, with applications in optical sensing, beam shaping, and structured cavities.