超高Q值 High Q-factor
Phononic crystal structures frequency response
Phononic crystals (PnCs) are periodic structures that are engineered to manipulate the propagation of acoustic or elastic waves. PnCs with phononic bandgap properties prevent the propagation of elastic waves in a specific frequency range. The formation of band structures in PnCs has been much investigated in physics, and comparisons made with other waves: while the electrons in a semiconductor can only occupy certain energy bands, a PnC allows acoustic waves in specific frequency ranges to travel through via the pass band; other frequencies are inhibited by the bandgap [https://doi.org/10.1016/S1369-7021(09)70315-3].
This application presents a frequency scan through the bandgap and the characterization of one specific frequency resonance located inside the bandgap, with a high quality factor of 444’681, likely limited by residual air damping.
Description
- Sample: SiN membranes patterned with phononic crystal structures
- Excitation: piezo, 2V, sinus
- Pressure: 10-5 mbar
- Magnification : 2.5x
- Field of View: 2.5 x 2.5 mm2
- Lateral resolution: 4.9 μm
- Excitation frequency: 1.15 to 1.35 MHz
- Instrument : DHM R-1000
- Stroboscopic module: High-Q model
Sample Courtesy
Prof. Dr. Albert Schliesser, and Dr Eric Langman, Niels Bohr Institute, Copenhagen University, Denmark, and QFactory ApS
Phononic crystal scanned over the bandgap 1.15 to 1.35 MHz
High-Q mode scanned by step of 0.01 Hz: Q=444’681
Examples of complex out-of-bandgap resonance modes
Picometer resolved vibration map
Vibration map obtained by decreasing the excitation voltage to 0.01 V
