Light diffusers have long been used in various applications, but conventional designs have limitations when it comes to controlling the optical directivity of the diffused light. Researchers have now introduced a groundbreaking solution - an electrically tunable light diffuser that leverages ultrasound technology in a nematic liquid crystal (LC) material.

The ultrasonic LC diffuser is a sophisticated structure consisting of an LC layer sandwiched between two glass discs and an ultrasonic transducer. By dividing the electrodes of the transducer in a circumferential direction, a resonant non-coaxial flexural vibration mode can be induced on the diffuser through precise control of electrical input signals.

When a continuous reversed-phase sinusoidal electric signal is applied to the transducer, it triggers the non-coaxial resonant flexural vibration mode on the glass disc. This, in turn, creates an acoustic radiation force at the boundary between the LC layer and glass discs, leading to a change in the molecular orientation of the LC and altering the distribution of transmitted light.

The angle of diffusion of the transmitted light is directly influenced by the voltage amplitude of the input signal, with the maximum diffusion angle observed at 16.0 V. Moreover, by adjusting the input voltages to different electrodes, researchers were able to rotate the vibrational distribution and diffusion directivity, offering a level of control previously unattainable with traditional light diffusers.

What sets this ultrasonic LC diffuser apart is its thin structure and absence of moving mechanical parts, making it a highly versatile and efficient solution for achieving tunable light-diffusing functionality with rotatable directivity. This innovation opens up new possibilities for a wide range of applications where precise control over light diffusion is essential.