Acoustic diodes and methods of using same
View Patent ↗Acoustic diodes, devices incorporating such diodes and methods of using such devices are disclosed. An acoustic diode may include a periodic acoustic grating and a uniform plate. The periodic acoustic grating may include a plurality of gratings. The uniform plate may foe separated from the periodic acoustic grating by a resonant cavity. The acoustic diode may be configured to have a first transmission efficiency for acoustic waves incident on the periodic acoustic grating that is greater than a second transmission efficiency for acoustic waves incident on the uniform plate. The acoustic waves may have a wavelength within a range of wavelengths. Devices incorporating the acoustic diode may include medical imaging devices, such as ultrasound devices, and noise reduction devices.
1. An acoustic diode comprising:
a periodic acoustic grating having a plurality of gratings; and
a uniform plate separated from the periodic acoustic grating by a resonant cavity,
wherein the acoustic diode is configured to have a first transmission efficiency for acoustic waves incident on the periodic acoustic grating that is greater than a second transmission efficiency for acoustic waves incident on the uniform plate, and
wherein the acoustic waves have a wavelength within a range of wavelengths.
2. The acoustic diode of claim 1 , wherein at least one grating of the plurality of gratings has a width of about 1.5 millimeters.
3. The acoustic diode of claim 1 , wherein a distance between adjacent gratings of the plurality of gratings is about 6 millimeters.
4. The acoustic diode of claim 1 , wherein the periodic acoustic grating has a thickness of about 3 millimeters.
5. The acoustic diode of claim 1 , wherein the uniform plate has a thickness of about 1.5 millimeters.
6. The acoustic diode of claim 1 , wherein the resonant cavity has a thickness of about 1.5 millimeters.
7. The acoustic diode of claim 1 , wherein the periodic acoustic grating comprises metal.
8. The acoustic diode of claim 1 , wherein the uniform plate comprises metal.
9. The acoustic diode of claim 1 , wherein the acoustic waves have a frequency of about 499 kHz to about 678 kHz.
10. The acoustic diode of claim 1 , wherein the acoustic diode exhibits a coincidence effect for acoustic waves incident on the periodic acoustic grating, and wherein an outgoing angle of the acoustic wave is equal to arcsin (c f /c p ), where c f is the velocity of the acoustic wave in the resonant cavity and c p is the velocity of the acoustic wave in the uniform plate.
11. The acoustic diode of claim 1 , wherein the first transmission efficiency is about 10% to about 60.8% for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
12. The acoustic diode of claim 1 , wherein the first transmission efficiency is greater than about 20%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
13. The acoustic diode of claim 1 , wherein the second transmission efficiency is less than 1%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
14. A medical imaging device comprising:
an acoustic wave generator configured to produce acoustic waves; and
an acoustic diode comprising:
a periodic acoustic grating having a plurality of gratings, and
a uniform plate separated from the periodic acoustic grating by a resonant cavity,
wherein the acoustic diode is configured to have a first transmission efficiency for acoustic waves incident on the periodic acoustic grating that is greater than a second transmission efficiency for acoustic waves incident on the uniform plate, and
wherein the acoustic waves have a wavelength within a range of wavelengths.
15. The medical imaging device of claim 14 , wherein the acoustic diode exhibits a coincidence effect for acoustic waves incident on the periodic acoustic grating, and wherein an outgoing angle of the acoustic wave is equal to arcsin (c f /c p ), where c f is the velocity of the acoustic wave in the resonant cavity and c p is the velocity of the acoustic wave in the uniform plate.
16. The medical imaging device of claim 14 , wherein the first transmission efficiency is about 10% to about 60.8% for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
17. The medical imaging device of claim 14 , wherein the first transmission efficiency is greater than about 20%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
18. The medical imaging device of claim 14 , wherein the second transmission efficiency is less than 1%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
19. A method of performing medical imaging, the method comprising:
producing, by an acoustic wave generator in an ultrasound device, an acoustic wave having a wavelength within a range of wavelengths;
transmitting the acoustic wave through an acoustic diode, wherein the acoustic wave passes through a periodic acoustic grating of the acoustic diode and a uniform plate of the acoustic diode, wherein the periodic acoustic grating comprises a plurality of gratings, wherein the uniform plate is separated from the periodic acoustic grating by a resonant cavity, and wherein the acoustic diode is configured to have a first transmission efficiency for acoustic waves incident on the periodic acoustic grating that is greater than a second transmission efficiency for acoustic waves incident on the uniform plate;
receiving the transmitted acoustic wave at a sensor; and
using the received acoustic wave to produce an image.
20. The method of claim 19 , further comprising:
reflecting substantially all acoustic waves incident on the uniform plate of the acoustic diode.
21. The method of claim 19 , further comprising exhibiting, by the acoustic diode, a coincidence effect for acoustic waves incident on the periodic acoustic grating, wherein an outgoing angle of the acoustic wave is equal to arcsin (c f /c p ), where c f is the velocity of the acoustic wave in the resonant cavity and c p is the velocity of the acoustic wave in the uniform plate.
22. The method of claim 19 , wherein transmitting the acoustic wave further comprises transmitting the acoustic wave such that the first transmission efficiency is about 10% to about 60.8% for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
23. The method of claim 19 , wherein transmitting the acoustic wave further comprises transmitting the acoustic wave such that the first transmission efficiency is greater than about 20%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
24. The method of claim 19 , wherein transmitting the acoustic wave further comprises transmitting the acoustic wave such that the second transmission efficiency is less than 1%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
25. A method of reducing noise, the method comprising:
producing an acoustic diode having a periodic acoustic grating and a uniform plate, wherein the periodic acoustic grating comprises a plurality of gratings, and wherein the uniform plate is separated from the periodic acoustic grating by a resonant cavity;
transmitting at least a portion of a first plurality of acoustic waves incident on the periodic acoustic grating; and
reflecting substantially all of a second plurality of acoustic waves incident on the uniform plate of the acoustic diode,
wherein a noise level is reduced on a side of the acoustic diode faced by the periodic acoustic grating.
26. The method of claim 25 , further comprising exhibiting, by the acoustic diode, a coincidence effect for acoustic waves incident on the periodic acoustic grating, wherein an outgoing angle of the acoustic wave is equal to arcsin (c f /c p ), where c f is the velocity of the acoustic wave in the resonant cavity and c p is the velocity of the acoustic wave in the uniform plate.
27. The method of claim 25 , wherein transmitting at least a portion of the first plurality of acoustic waves further comprises transmitting such that a first transmission efficiency of the acoustic diode is about 10% to about 60.8% for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
28. The method of claim 25 , wherein transmitting at least a portion of the first plurality of acoustic waves further comprises transmitting such that a first transmission efficiency of the acoustic diode is greater than about 20%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.
29. The method of claim 25 , wherein transmitting at least a portion of the first plurality of acoustic waves further comprises transmitting such that a second transmission efficiency of the acoustic diode is less than 1%, on average, for acoustic waves having a frequency of about 499 kHz to about 678 kHz.