Multi-focus Beam Formation And Beam Steering Using An Acoustic Lens And Lens Rotation To Create Large Lesions In Ultrasound Thermal Therapy

2005 ◽  
Author(s):  
X. Wu
Keyword(s):  
Beam Steering ◽  
Thermal Therapy ◽  
Focus Beam ◽  
Acoustic Lens ◽  
Beam Formation

scholarly journals Grating Lobe-Free Beam Steering through Optical Phase Array Using Phase-Compensated Two Index-Mismatched Silicon Wires-Based Emitters

2020 ◽  
Vol 10 (4) ◽  
pp. 1225
Author(s):  
Rong-An Zhang ◽  
Ting-Sheng Lin ◽  
Wai-Ting Liu ◽  
Shih-Hsiang Hsu ◽  
Che-Chang Chang
Keyword(s):  
Phase Shifter ◽  
Beam Steering ◽  
Thermal Control ◽  
Phase Shifters ◽  
Phase Array ◽  
Optical Phase ◽  
Grating Lobe ◽  
Half Wavelength ◽  
Beam Formation ◽  
Free Beam

The beam formation can be treated as the diffraction pattern. A 1-D light detection and ranging beam steering could be derived through a phase shifter array using Rayleigh–Sommerfeld Diffraction, which is then utilized to demonstrate grating lobe-free beam steering from the optical phase array emitter with half-wavelength pitches. The half-wavelength pitch cannot demonstrate beam formation without any evanescent coupling blocking between emitters. Here, two index-mismatched silicon wires in the emitter array are proposed by the optical phase compensation through waveguide width adjustment, to avoid the complex and addressable thermal control on the phase shifters. Moreover, the same output optical waveguide mode needs to be further considered to demonstrate the grating lobe-free beam steering. In order to get the adiabatic connection between two different pitches between the phase shifter and emitter, an optical path equalization will also be applied.

scholarly journals Beam Formation and Vernier Steering Off of a Rough Surface

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 871
Author(s):  
Eric K. Nagamine ◽  
Kenneth W. Burgi ◽  
Samuel D. Butler
Keyword(s):  
Rough Surface ◽  
Beam Steering ◽  
Superior Performance ◽  
Line Of Sight ◽  
Beam Formation ◽  
Wavefront Shaping ◽  
Inverse Diffusion ◽  
Scanning Range ◽  
Iterative Feedback ◽  
Illumination Source

Wavefront shaping can refocus light after it reflects from an optically rough surface. One proposed use case of this effect is in indirect imaging; if any rough surface could be turned into an illumination source, objects out of the direct line of sight could be illuminated. In this paper, we demonstrate the superior performance of a genetic algorithm compared to other iterative feedback-based wavefront shaping algorithms in achieving reflective inverse diffusion for a focal plane system. Next, the ability to control the pointing direction of the refocused beam with high precision over a narrow angular range is demonstrated, though the challenge of increasing the overall scanning range of the refocused beam remains. The method of beam steering demonstrated in this paper could act as a vernier adjustment to a coarse adjustment offered by another method.

scholarly journals Improving ultrasound images with elevational angular compounding based on acoustic refraction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Parastoo Afshari ◽  
Christian Zakian ◽  
Vasilis Ntziachristos
Keyword(s):  
Low Cost ◽  
Beam Steering ◽  
Speckle Noise ◽  
Angular Width ◽  
Speckle Reduction ◽  
Ultrasound Images ◽  
Coherent Noise ◽  
Tissue Samples ◽  
Acoustic Lens ◽  
Excised Tissue

Abstract Ultrasound imaging is affected by coherent noise or speckle, which reduces contrast and overall image quality and degrades the diagnostic precision of the collected images. Elevational angular compounding (EAC) is an attractive means of addressing this limitation, since it reduces speckle noise while operating in real-time. However, current EAC implementations rely on mechanically rotating a one-dimensional (1D) transducer array or electronically beam steering of two-dimensional (2D) arrays to provide different elevational imaging angles, which increases the size and cost of the systems. Here we present a novel EAC implementation based on a 1D array, which does not necessitate mechanically rotating the transducer. The proposed refraction-based elevational angular compounding technique (REACT) instead utilizes a translating cylindrical acoustic lens that steers the ultrasound beam along the elevational direction. Applying REACT to investigate phantoms and excised tissue samples demonstrated superior suppression of ultrasound speckle noise compared to previous EAC methods, with up to a two-fold improvement in signal- and contrast-to-noise ratios. The effects of elevational angular width on speckle reduction was further investigated to determine the appropriate conditions for applying EAC. This study introduces acoustic refractive elements as potential low cost solutions to noise reduction, which could be integrated into current medical ultrasound devices.

Symmetric-pair antennas for beam steering, direction finding or isotropic-reception gain

1991 ◽  
Vol 138 (4) ◽  
pp. 368 ◽  
Author(s):  
R. Benjamin ◽  
W. Titze ◽  
P.V. Brennan ◽  
H.D. Griffiths
Keyword(s):  
Beam Steering ◽  
Direction Finding ◽  
Symmetric Pair

High frequency induced thermal therapy (HITT) – four modalities, more possibilities. how and when to do it?

2008 ◽  
Vol 29 (S 1) ◽  
Author(s):  
H Stoyan ◽  
K Katzarov ◽  
Z Dunkov ◽  
D Takov ◽  
D Stoyanova ◽  
...  
Keyword(s):  
High Frequency ◽  
Thermal Therapy

Phononic-Crystal Acoustic Lens by Design for Energy-Transmission Devices

2012 ◽  
Vol 132 (5) ◽  
pp. 686-690
Author(s):  
Yusuke Kanno ◽  
Kenji Tsuruta ◽  
Kazuhiro Fujimori ◽  
Hideki Fukano ◽  
Shigeji Nogi
Keyword(s):  
Phononic Crystal ◽  
Energy Transmission ◽  
Acoustic Lens

Electromagnetically Driven 2-axis Optical Beam Steering MEMS Mirror and Its Dependence of Actuation on Magnetic Field

2010 ◽  
Vol 130 (4) ◽  
pp. 107-112 ◽  
Author(s):  
Yoshiyuki Watanabe ◽  
Yutaka Abe ◽  
Shinnosuke Iwamatsu ◽  
Seiya Kobayashi ◽  
Yoshiyuki Takahashi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Beam Steering ◽  
Optical Beam
Sign in / Sign up

Export Citation Format

Share Document