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Terahertz time-domain spectroscopy (THz-TDS) employs sub-picosecond pulses to probe dielectric properties of materials giving as a result a 3-dimensional hyperspectral data cube. The spatial resolution of THz images is primarily limited by…

Nonlinear propagation of intense femtosecond laser pulses in bulk transparent media leads to a specific propagation regime, termed femtosecond filamentation, which in turn produces dramatic spectral broadening, or superbroadening, termed…

In this work we report a theoretical study of the lateral resolution granted by a simple glass microcylinder. In this 2D study, we had in mind the 3D analogue -- a microsphere whose ability to form a deeply subwavelength and strongly…

Optics · Physics 2022-03-03 R. Heydarian , C. Simovski

Ultrasound vascular imaging is limited by acoustic diffraction, restricting visualization of microvessels essential for understanding organ function and disease. Label-free super-resolution methods exploiting endogenous red blood cells have…

In this work, finite-difference time-domain (FDTD) method is employed to justify the superlensing effect of left-handed material (LHM) slabs. Our results demonstrate that subwavelength resolution can be achieved by realistic LHM slabs with…

Materials Science · Physics 2007-05-23 X. S. Rao , C. K. Ong

Low-bandwidth communication, such as underwater acoustic communication, is limited by best-case data rates of 30--50 kbit/s. This renders such channels unusable or inefficient at best for single image, video, or other bandwidth-demanding…

Image and Video Processing · Electrical Eng. & Systems 2020-09-23 Jesper Haahr Christensen , Lars Valdemar Mogensen , Ole Ravn

An experimental evidence of subwavelength imaging with a "lens", which is a uniaxial negative permittivity wire medium slab, is reported. The slab is formed by gratings of long thin parallel conducting cylinders. Taking into account the…

Single-beam super-resolution microscopy, also known as superlinear microscopy, exploits the nonlinear response of fluorescent probes in confocal microscopy. The technique requires no complex purpose-built system, light field modulation, or…

Optical microscopy has so far been restricted to superficial layers, leaving many important biological questions unanswered. Random scattering causes the ballistic focus, which is conventionally used for image formation, to decay…

Optics · Physics 2012-08-28 Ke Si , Reto Fiolka , Meng Cui

We propose a new technique to obtain super-resolution images with radio interferometer using sparse modeling. In standard radio interferometry, sampling of ($u$, $v$) is quite often incomplete and thus obtaining an image from observed…

Instrumentation and Methods for Astrophysics · Physics 2014-07-10 Mareki Honma , Kazunori Akiyama , Makoto Uemura , Shiro Ikeda

Previous work established fundamental bounds on subwavelength resolution for the radar range resolution problem, called superradar [Phys. Rev. Appl. 20, 064046 (2023)]. In this work, we identify the optimal waveforms for distinguishing the…

Signal Processing · Electrical Eng. & Systems 2025-02-14 Andrew N. Jordan , John C. Howell , Achim Kempf , Shunxing Zhang , Derek White

Terahertz (THz) imaging provides cutting edge technique in biology, medical sciences and non-destructive evaluation. However, due to the long wavelength of the THz wave, the obtained resolution of THz imaging is normally a few hundred…

Optics · Physics 2013-10-22 Jiayu Zhao , Wei Chu , Lanjun Guo , Zhi Wang , Ya Cheng , Weiwei Liu , Zhizhan Xu

Sonography techniques use multiple transducer elements for tissue visualization. Signals detected at each element are sampled prior to digital beamforming. The sampling rates required to perform high resolution digital beamforming are…

Information Theory · Computer Science 2013-07-25 Tanya Chernyakova , Yonina C. Eldar

Waveform decomposition is needed as a first step in the extraction of various types of geometric and spectral information from hyperspectral full-waveform LiDAR echoes. We present a new approach to deal with the "Pseudo-monopulse" waveform…

Signal Processing · Electrical Eng. & Systems 2023-06-12 Yuhao Xia , Shilong Xu , Hui Shao , Ahui Hou , Jiajie Fang , Fei Han , Youlong Chen , Jiaqi Wen , Yuwei Chen , Yihua Hu

Perfect lensing using negative refractive index materials and radiationless electromagnetic interference both provide extreme subwavelength focusing by "amplifying" evanescent wave components that are usually lost. This paper provides a…

Optics · Physics 2015-06-03 Reuven Gordon

Field characterization methods using a scattering target in the absence of a point-like receiver have been well described in which scattering is recorded by a relatively large receiver located outside the field of measurement.…

Instrumentation and Detectors · Physics 2015-01-29 Gregory T. Clement , Hideyuki Nomura , Tomoo Kamakura

Supercontinua generated in highly non-linear fibers by ultrashort-pulse lasers can be used for high resolution Fourier transform absorption spectroscopy. The practical advantages of these bright ultrabroadband light sources for spectroscopy…

This paper provides a theoretical analysis of diffraction-limited superresolution, demonstrating that arbitrarily close point sources can be resolved in ideal situations. Precisely, we assume that the incoming signal is a linear combination…

Optimization and Control · Mathematics 2015-08-14 Geoffrey Schiebinger , Elina Robeva , Benjamin Recht

We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding…

Optics · Physics 2009-11-10 Michael W. Feise , Yuri S. Kivshar

Resolution enhancements are often desired in imaging applications where high-resolution sensor arrays are difficult to obtain. Many computational imaging methods have been proposed to encode high-resolution scene information on…

Image and Video Processing · Electrical Eng. & Systems 2018-10-29 Kevin Beale , Jianbo Chen , Kevin F. Kelly , Justin Romberg