In a new development, researchers at the Technical University of Munich and Helmholtz Zentrum Munchen have been successful in developing the world’s smallest ultrasound detector. The detector is based on miniaturized photonic circuits placed on the top of a silicon chip.
The size of the new detectors is 100 times smaller than an average human hair. But it can visualize details much smaller than what was previously possible, leading to what is termed as super-resolution imaging.
Size of Piezoelectric Detectors determines Imaging Resolution
Meanwhile, since 1950, when medical ultrasound imaging was developed, the primary focus of core detection technology of ultrasound waves is on using piezoelectric detectors. The size of piezoelectric detector employed determines the imaging resolution achieved with ultrasound. If size of the piezoelectric detector employed reduced further results in higher resolution. Further, it can offer smaller, tightly packed one or two dimensional ultrasound arrangement with improved ability to distinguish features in the imaged material or tissue. On the other hand, if the size of piezoelectric detectors further reduced, it damages their sensitivity dramatically, which makes them unusable for practical purposes.
Miniaturization of optical components widely employs silicon photonics technology, and the technology involves packing optical components tightly on the small surface of a silicon chip. Meanwhile, silicon does not exhibit any piezoelectricity, but its ability to restrict light in dimensions smaller than the optical wavelength already widely exploited for the creation of miniaturized photonic circuits.
Capitalizing on the advantages of these photonic circuits, researchers at Technical University of Munich and Helmholtz built the smallest ultrasound detector of the world – the silicon waveguide-etalon detector (SWED). Functionally, SWED monitors change in light intensity transmitted through miniaturized photonic circuits, instead of taking down voltage from piezoelectric crystals.