Acoustic impedance matching structures can be used on capacitive micromachined ultrasonic transducers (CMUT) to increase acoustic energy transmission into the load medium. Our contribution contains a systematic study of the viability of the two-photon-polymerization lithography process for the fabrication of acoustic impedance matching metamaterials. For this purpose, acoustic simulations were conducted to find optimized dimensions of the matching structure. Based on the proposed dimensions, parameter sweeps were manufactured on substitute substrates, resulting in a viable parameter space for the direct fabrication on CMUT devices.
Structuring polymers on micro-electro-mechanical-systems (MEMS) for the manufacturing of acoustical and optical metamaterials using the two-photon polymerization process depends on reliable and controllable regulation of the intensity. Reflecting surfaces, diffracting elements and structures with poor heat dissipation can be problematic obstacles for the incident focused and pulsed laser beam. Thermal and optical simulations were performed and compared to test structures. A compensated fabrication approach was successfully applied to create optimized conditions in the polymerized volume.