Whispering gallery resonators made out of lithium niobate allow for optical parametric oscillation and frequency comb generation employing the outstanding second-order nonlinear-optical properties of this material. An important knob to tune and control these processes is. e. g. https://www.kaliboat.com/product-category/food-servicecommercial-kitchen-equipmentfood-preparation-equipmentcommercial-mixers/