An official website of the United States government
A new lens capability for three-dimensional (3D) focal control is presented using an optofluidic system consisting ofn × narrayed liquid prisms. Each prism module contains two immiscible liquids in a rectangular cuvette. Using the electrowetting effect, the shape of the fluidic interface can be rapidly adjusted to create its straight profile with the prism’s apex angle. Consequently, an incoming ray is steered at the tilted interface due to the refractive index difference between two liquids. To achieve 3D focal control, individual prisms in the arrayed system are simultaneously modulated, allowing incoming light rays to be spatially manipulated and converged on a focal point located atPfocal(fx,fy,fz) in 3D space. Analytical studies were conducted to precisely predict the prism operation required for 3D focal control. Using three liquid prisms positioned on thex-,y-, and 45°-diagonal axes, we experimentally demonstrated 3D focal tunability of the arrayed optofluidic system, achieving focal tuning along lateral, longitudinal, and axial directions as wide as 0 ≤ fx ≤ 30 mm, 0 ≤ fy ≤ 30 mm, and 500 mm ≤ fz ≤ ∞. This focal tunability of the arrayed system allows for 3D control of the lens’s focusing power, which could not be attained by solid-type optics without the use of bulky and complex mechanical moving components. This innovative lens capability for 3D focal control has potential applications in eye-movement tracking for smart displays, autofocusing of smartphone cameras, or solar tracking for smart photovoltaic systems.
more »
« less
Calibration method for a multi-focus microscopic 3D imaging system
This Letter presents a novel, to the best of our knowledge, method to calibrate multi-focus microscopic structured-light three-dimensional (3D) imaging systems with an electrically adjustable camera focal length. We first leverage the conventional method to calibrate the system with a reference focal lengthf0. Then we calibrate the system with other discrete focal lengthsfiby determining virtual features on a reconstructed white plane usingf0. Finally, we fit the polynomial function model using the discrete calibration results forfi. Experimental results demonstrate that our proposed method can calibrate the system consistently and accurately.
more »
« less
- Award ID(s):
- 1763689
- PAR ID:
- 10440345
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Letters
- Volume:
- 48
- Issue:
- 16
- ISSN:
- 0146-9592; OPLEDP
- Format(s):
- Medium: X Size: Article No. 4348
- Size(s):
- Article No. 4348
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
We present a novel symbolic reasoning engine for SQL which can efficiently generate an inputIfornqueriesP1, ⋯,Pn, such that their outputs onIsatisfy a given property (expressed in SMT). This is useful in different contexts, such as disproving equivalence of two SQL queries and disambiguating a set of queries. Our first idea is to reason about an under-approximation of eachPi— that is, a subset ofPi’s input-output behaviors. While it makes our approach both semantics-aware and lightweight, this idea alone is incomplete (as a fixed under-approximation might miss some behaviors of interest). Therefore, our second idea is to perform search over an expressive family of under-approximations (which collectively cover all program behaviors of interest), thereby making our approach complete. We have implemented these ideas in a tool, Polygon, and evaluated it on over 30,000 benchmarks across two tasks (namely, SQL equivalence refutation and query disambiguation). Our evaluation results show that Polygon significantly outperforms all prior techniques.more » « less
-
We describe the confining instabilities of a proposed quantum spin liquid underlying the pseudogap metal state of the hole-doped cuprates. The spin liquid can be described by a SU(2) gauge theory ofNf= 2 massless Dirac fermions carrying fundamental gauge charges—this is the low-energy theory of a mean-field state of fermionic spinons moving on the square lattice withπ-flux per plaquette in the ℤ2center of SU(2). This theory has an emergent SO(5)fglobal symmetry and is presumed to confine at low energies to the Néel state. At nonzero doping (or smaller Hubbard repulsionUat half-filling), we argue that confinement occurs via the Higgs condensation of bosonic chargons carrying fundamental SU(2) gauge charges also moving inπℤ2-flux. At half-filling, the low-energy theory of the Higgs sector hasNb= 2 relativistic bosons with a possible emergent SO(5)bglobal symmetry describing rotations between ad-wave superconductor, period-2 charge stripes, and the time-reversal breaking “d-density wave” state. We propose a conformal SU(2) gauge theory withNf= 2 fundamental fermions,Nb= 2 fundamental bosons, and a SO(5)f×SO(5)bglobal symmetry, which describes a deconfined quantum critical point between a confining state which breaks SO(5)fand a confining state which breaks SO(5)b. The pattern of symmetry breaking within both SO(5)s is determined by terms likely irrelevant at the critical point, which can be chosen to obtain a transition between Néel order andd-wave superconductivity. A similar theory applies at nonzero doping and largeU, with longer-range couplings of the chargons leading to charge order with longer periods.more » « less
-
The evolutionary histories of many polyploid plant species are difficult to resolve due to a complex interplay of hybridization, incomplete lineage sorting, and missing diploid progenitors. In the case of octoploid strawberry with four subgenomes designated ABCD, the identities of the diploid progenitors for subgenomes C and D have been subject to much debate. By integrating new sequencing data from North American diploids with reticulate phylogeny and admixture analyses, we uncovered introgression from an extinct or unsampled species in the clade ofFragaria viridis,Fragaria nipponica, andFragaria nilgerrensisinto the donor of subgenome A of octoploidFragariaprior to its divergence fromF. vescasubsp. bracteata. We also detected an introgression event fromF. iinumaeinto an ancestor ofF. nipponicaandF. nilgerrensis.Using an LTR-age-distribution-based approach, we estimate that the octoploid and its intermediate hexaploid and tetraploid ancestors emerged approximately 0.8, 2, and 3 million years ago, respectively. These results provide an explanation for previous reports ofF. viridisandF. nipponicaas donors of the C and D subgenomes and suggest a greater role than previously thought for homoploid hybridization in the diploid progenitors of octoploid strawberry. The integrated set of approaches used here can help advance polyploid genome analysis in other species where hybridization and incomplete lineage sorting obscure evolutionary relationships.more » « less
-
Although nodal spin-triplet topological superconductivity appears probable in uranium ditelluride (UTe2), its superconductive order parameter Δkremains unestablished. In theory, a distinctive identifier would be the existence of a superconductive topological surface band, which could facilitate zero-energy Andreev tunneling to an s-wave superconductor and also distinguish a chiral from a nonchiral Δkthrough enhanced s-wave proximity. In this study, we used s-wave superconductive scan tips and detected intense zero-energy Andreev conductance at the UTe2(0-11) termination surface. Imaging revealed subgap quasiparticle scattering interference signatures witha-axis orientation. The observed zero-energy Andreev peak splitting with enhanced s-wave proximity signifies that Δkof UTe2is a nonchiral state:B1u,B2u, orB3u. However, if the quasiparticle scattering along theaaxis is internodal, then a nonchiralB3ustate is the most consistent for UTe2.more » « less
