skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Deep, sub-wavelength acoustic patterning of complex and non-periodic shapes on soft membranes supported by air cavities
Arbitrary patterning of micro-objects in liquid is crucial to many biomedical applications. Among conventional methodologies, acoustic approaches provide superior biocompatibility but are intrinsically limited to producing periodic patterns at low resolution due to the nature of standing waves and the coupling between fluid and structure vibrations. This work demonstrates a near-field acoustic platform capable of synthesizing high resolution, complex and non-periodic energy potential wells. A thin and viscoelastic membrane is utilized to modulate the acoustic wavefront on a deep, sub-wavelength scale by suppressing the structural vibration selectively on the platform. Using 3 MHz excitation ( λ ∼ 500 μm in water), we have experimentally validated such a concept by realizing patterning of microparticles and cells with a line resolution of 50 μm (one tenth of the wavelength). Furthermore, massively parallel patterning across a 3 × 3 mm 2 area has been achieved. This new acoustic wavefront modulation mechanism is powerful for manufacturing complex biologic products.  more » « less
Award ID(s):
1711507
PAR ID:
10165811
Author(s) / Creator(s):
; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Lab on a Chip
Volume:
19
Issue:
21
ISSN:
1473-0197
Page Range / eLocation ID:
3714 to 3725
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Lab on a Chip)
    Acoustic patterning of micro-particles has many important biomedical applications. However, fabrication of such microdevices is costly and labor-intensive. Among conventional fabrication methods, photo-lithography provides high resolution but is expensive and time consuming, and not ideal for rapid prototyping and testing for academic applications. In this work, we demonstrate a highly efficient method for rapid prototyping of acoustic patterning devices using laser manufacturing. With this method we can fabricate a newly designed functional acoustic device in 4 hours. The acoustic devices fabricated using this method can achieve sub-wavelength, complex and non-periodic patterning of microparticles and biological objects with a spatial resolution of 60 μm across a large active manipulation area of 10 × 10 mm 2 . 
    more » « less
  2. ; ; ; ; ; (, The Analyst)
    Mid-infrared Spectroscopic Imaging (MIRSI) provides spatially-resolved molecular specificity by measuring wavelength-dependent mid-infrared absorbance. Infrared microscopes use large numerical aperture objectives to obtain high-resolution images of heterogeneous samples. However, the optical resolution is fundamentally diffraction-limited, and therefore wavelength-dependent. This significantly limits resolution in infrared microscopy, which relies on long wavelengths (2.5 μm to 12.5 μm) for molecular specificity. The resolution is particularly restrictive in biomedical and materials applications, where molecular information is encoded in the fingerprint region (6 μm to 12 μm), limiting the maximum resolving power to between 3 μm and 6 μm. We present an unsupervised curvelet-based image fusion method that overcomes limitations in spatial resolution by augmenting infrared images with label-free visible microscopy. We demonstrate the effectiveness of this approach by fusing images of breast and ovarian tumor biopsies acquired using both infrared and dark-field microscopy. The proposed fusion algorithm generates a hyperspectral dataset that has both high spatial resolution and good molecular contrast. We validate this technique using multiple standard approaches and through comparisons to super-resolved experimentally measured photothermal spectroscopic images. We also propose a novel comparison method based on tissue classification accuracy. 
    more » « less
  3. ; ; ; (, Applied Physics Letters)
    We propose a nonlinear acoustic metasurface concept by exploiting the nonlinearity of locally resonant unit cells formed by curved beams. The analytical model is established to explore the nonlinear phenomenon, specifically the second-harmonic generation (SHG) of the nonlinear unit cell, and validated through numerical and experimental studies. By tailoring the phase gradient of the unit cells, nonlinear acoustic metasurfaces are developed to demultiplex different frequency components and achieve anomalous wavefront control of SHG in the transmitted region. To this end, we numerically demonstrate wave steering, wave focusing, and self-bending propagation. Our results show that the proposed nonlinear metasurface provides an effective and efficient platform to achieve significant SHG and separate different harmonic components for wavefront control of individual harmonics. Overall, this study offers an outlook to harness nonlinear effects for acoustic wavefront tailoring and develops potential toward advanced technologies to manipulate acoustic waves. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, Proceedings of the SPIE)
    Schmidt, Dirk; Schreiber, Laura; Vernet, Elise (Ed.)
    We are upgrading and refurbishing the first-generation adaptive-secondary mirror (ASM)-based AO system on the 6.5-m MMT in Arizona, in an NSF MSIP-funded program that will create a unique facility specialized for exoplanet characterization. This update includes a third-generation ASM with embedded electronics for low power consumption, two pyramid wavefront sensors (optical and near-IR), and an upgraded ARIES science camera for high-resolution spectroscopy (HRS) from 1-5 μm and MMT-POL science camera for sensitive polarization mapping. Digital electronics have been incorporated into each of the 336 actuators, simplifying hub-level electronics and reducing the total power to 300 W, down from 1800 W in the legacy system — reducing cooling requirements from active coolant to passive ambient cooling. An improved internal control law allows for electronic damping and a faster response. The dual pyramid wavefront sensors allow for a choice between optical or IR wavefront sensing depending on guide star magnitude, color, and extinction. The HRS upgrade to ARIES enables crosscorrelation of molecular templates to extract atmospheric parameters of exoplanets. The combination of these upgrades creates a workhorse instrument for exoplanet characterization via AO and HRS to separate planets from their host stars, with broad wavelength coverage and polarization to probe a range of molecular species in exoplanet atmospheres. 
    more » « less
  5. ; ; ; ; (, Optics Express)
    Focusing light through turbid media using wavefront shaping generally requires a noninvasive guide star to provide feedback on the focusing process. Here we report a photoacoustic guide star mechanism suitable for wavefront shaping through a scattering wall that is based on the fluctuations in the photoacoustic signals generated in a micro-vessel filled with flowing absorbers. The standard deviation of photoacoustic signals generated from random distributions of particles is dependent on the illumination volume and increases nonlinearly as the illumination volume is decreased. We harness this effect to guide wavefront shaping using the standard deviation of the photoacoustic response as the feedback signal. We further demonstrate sub-acoustic resolution optical focusing through a diffuser with a genetic algorithm optimization routine. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email