arXiv subjects

Takayuki Hoshi

Publications and source records attributed to Takayuki Hoshi.

5 recordsLinked to original sources

arXiv2026

Reversible vertical positioning of acoustically levitated particle using a spiral reflector

Dynamic positioning in acoustic levitation typically depends on active control of the transducers phases, which necessitates complex driving electronics. While mechanically actuated reflectors offer a simpler alternative, achieving reversible transport along the vertical axis solely through mechanical actuation remains challenging. Here, we demonstrate vertical particle translation using a rotating spiral reflector with a half-wavelength pitch. With the rotation axis laterally offset relative to the acoustic focus, the spiral surface functions as a series of translating slopes. Experimental and numerical results confirm stable, bidirectional transport, yielding a vertical displacement of approximately $0.58\lambda$ per revolution and a maximum height of $3.18\lambda$, with radial confinement maintained within $0.24\lambda$. This approach provides a cost-effective solution for non-contact sample handling without active phase control.

physics.app-ph↗

arXiv2024

Mid-Air Single-Sided Acoustic Levitation in High-Pressure Regions of Zero-Order Bessel Beams

Acoustic levitation enables non-contact manipulation using sound waves. While conventional methods entrap particles at pressure nodes (zero-pressure region surrounded by high-pressure), we demonstrate stable acoustic levitation and translation in mid-air within a high-pressure axial core of a single-sided zero-order Bessel beam for the first time. The trap operates at a long working distance, up to 397 mm ($46.6 \lambda$), supports simultaneous multi-particle levitation, and maintains stability over obstacles. Our work establishes a new paradigm for single-sided acoustic manipulation in mid-air.

physics.app-ph↗

arXiv2019

Sonovortex: Aerial Haptic Layer Rendering by Aerodynamic Vortex and Focused Ultrasound

In this paper, a method of rendering aerial haptics that uses an aerodynamic vortex and focused ultrasound is presented. Significant research has been conducted on haptic applications based on multiple phenomena such as magnetic and electric fields, focused ultrasound, and laser plasma. By combining multiple physical quantities; the resolution, distance, and magnitude of force are enhanced. To combine multiple tactile technologies, basic experiments on resolution and discrimination threshold are required. Separate user studies were conducted using aerodynamic and ultrasonic haptics. Moreover, the perception of their superposition, in addition to their resolution, was tested. Although these fields cause no direct interference, the system enables the simultaneous perception of the tactile feedback of both stimuli. The results of this study are expected to contribute to expanding the expression of aerial haptic displays based on several principles.

cs.HC↗

arXiv2015

Fairy Lights in Femtoseconds: Aerial and Volumetric Graphics Rendered by Focused Femtosecond Laser Combined with Computational Holographic Fields

We present a method of rendering aerial and volumetric graphics using femtosecond lasers. A high-intensity laser excites a physical matter to emit light at an arbitrary 3D position. Popular applications can then be explored especially since plasma induced by a femtosecond laser is safer than that generated by a nanosecond laser. There are two methods of rendering graphics with a femtosecond laser in air: Producing holograms using spatial light modulation technology, and scanning of a laser beam by a galvano mirror. The holograms and workspace of the system proposed here occupy a volume of up to 1 cm^3; however, this size is scalable depending on the optical devices and their setup. This paper provides details of the principles, system setup, and experimental evaluation, and discussions on scalability, design space, and applications of this system. We tested two laser sources: an adjustable (30-100 fs) laser which projects up to 1,000 pulses per second at energy up to 7 mJ per pulse, and a 269-fs laser which projects up to 200,000 pulses per second at an energy up to 50 uJ per pulse. We confirmed that the spatiotemporal resolution of volumetric displays, implemented with these laser sources, is 4,000 and 200,000 dots per second. Although we focus on laser-induced plasma in air, the discussion presented here is also applicable to other rendering principles such as fluorescence and microbubble in solid/liquid materials.

cs.GR↗

arXiv2013

Three-dimensional Mid-air Acoustic Manipulation by Ultrasonic Phased Arrays

The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that expanded-polystyrene particles of 0.6 mm and 2 mm in diameter could be manipulated by our proposed method.

physics.class-ph↗