Phononic circuit components

A phononic circuit component including a membrane coupled to a substrate, the membrane including a region having an array of holes and a channel provided in the substrate beneath the region so that the region is released from the substrate, thereby allowing the region to propagate transverse acoustic waves, wherein the holes are spaced by a distance that is at least one of:

• a) less than 10% of the wavelength of the acoustic waves;
• b) less than 5% of the wavelength of the acoustic waves;
• c) less than 2% of the wavelength of the acoustic waves;
• d) less than 1% of the wavelength of the acoustic waves;
• e) less than 20% of the width of the region;
• f) less than 15% of the width of the region;
• g) less than 10% of the width of the region;
• h) less than 5% of the width of the region;
• and,
• i) less than 2% of the width of the region;
• wherein the region is at least one of:
• a) a single mode acoustic waveguide;
• b) a multi-mode acoustic waveguide;
• c) a tunnel barrier;
• d) an acoustic waveguide including one or more pass bands;
• e) an acoustic waveguide including one or more stop bands;
• and,
• f) a resonator;
• and wherein if the region includes a tunnel barrier, and a ratio of reflection to tunnelling is based on a length of the region and an amplitude exponential decay length given by the equation:
• γ
• =
• (
• (
• π
• L
• x
• )
• -
• Ω
• 2
• ⁢
• ρ
• σ
• )
• -
• 1
• /
• 2
• where:
• Ω is an acoustic wave frequency,
• y is the amplitude exponential decay length,
• σ is a membrane tensile stress,
• ρ is a membrane material density, and
• Lx is the region width.