Ultrasonic subwavelength phase conjugated mirror with a layer of bubbles.
ULTRASONICS 2017;
78:110-114. [PMID:
28334635 DOI:
10.1016/j.ultras.2017.03.008]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/09/2017] [Accepted: 03/12/2017] [Indexed: 06/06/2023]
Abstract
A single layer of gas bubbles in a yield-stress fluid is experimentally shown to behave as a phase-conjugated (PC) mirror with a thickness 250 times smaller than the wavelength (0.14mm-diameter bubbles for phase-conjugation at 40kHz). A high amplitude pump wave at frequency 80kHz interacts with a lower amplitude probe wave centered at 40kHz. A PC-reflection coefficient of 0.15 is obtained for a 50kPa pump. A perturbative second-order theory is shown to quantitatively describe the experimental observations.
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