Imaging Below Diffraction Limit Using Superlens and Hyperlens

2007 ◽  
Author(s):  
Xiang Zhang
Keyword(s):  
Diffraction Limit

Confocal Raman mapping

1992 ◽  
Vol 50 (2) ◽  
pp. 1514-1515
Author(s):  
J. Barbillat ◽  
M. Delhaye ◽  
P. Dhamelincourt
Keyword(s):  
Chemical Species ◽  
Diffraction Limit ◽  
Microscopic Level ◽  
Raman Mapping ◽  
Complete Spectrum ◽  
Laser Illumination ◽  
Ccd Detector ◽  
Raman Microprobe ◽  
Photodiode Array ◽  
Raman Image

Raman mapping, with a spatial resolution close to the diffraction limit, can help to reveal the distribution of chemical species at the surface of an heterogeneous sample.As early as 1975,three methods of sample laser illumination and detector configuration have been proposed to perform Raman mapping at the microscopic level (Fig. 1),:- Point illumination:The basic design of the instrument is a classical Raman microprobe equipped with a PM tube or either a linear photodiode array or a two-dimensional CCD detector. A laser beam is focused on a very small area ,close to the diffraction limit.In order to explore the whole surface of the sample,the specimen is moved sequentially beneath the microscope by means of a motorized XY stage. For each point analyzed, a complete spectrum is obtained from which spectral information of interest is extracted for Raman image reconstruction.- Line illuminationA narrow laser line is focused onto the sample either by a cylindrical lens or by a scanning device and is optically conjugated with the entrance slit of the stigmatic spectrograph.

Quantitative depth evaluation of microgrooves on polymer material beyond the diffraction limit

2019 ◽  
Vol 59 ◽  
pp. 56-65
Author(s):  
Shiwei Ye ◽  
Satoru Takahashi ◽  
Masaki Michihata ◽  
Kiyoshi Takamasu ◽  
Hans Nørgaard Hansen ◽  
...  
Keyword(s):  
Polymer Material ◽  
Diffraction Limit

scholarly journals Breaking the acoustic diffraction limit with an arbitrary shape acoustic magnifying lens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali Abdolali ◽  
Hooman Barati Sedeh ◽  
Mohammad Hosein Fakheri ◽  
Chen Shen ◽  
Fei Sun
Keyword(s):  
Arbitrary Shape ◽  
Design Principle ◽  
Focused Ultrasound ◽  
Effective Medium Theory ◽  
Wide Spectrum ◽  
Diffraction Limit ◽  
Far Field ◽  
Biomedical Sensors ◽  
Focused Ultrasound Surgery ◽  
Unit Cells

AbstractBased on the transformation acoustics methodology, the design principle for achieving an arbitrary shape magnifying lens (ASML) is proposed. Contrary to the previous works, the presented ASML is competent of realizing far-field high resolution images and breaking the diffraction limit, regardless of the position of the utilized sources. Therefore, objects locating within the designed ASML can be properly resolved in the far-field region. It is shown that the obtained material through the theoretical investigations becomes an acoustic null medium (ANM), which has recently gained a significant attention. Besides the homogeneity of ANM, which makes it an implementable material, it is also independent of the perturbation in the geometry of the lens, in such a way that the same ANM can be used for different structural topologies. The obtained ANM has been implemented via acoustics unit cells formed by membranes and side branches with open ends and then was utilized to realize an ASML with the aid of effective medium theory. It is shown that the far-field results of an ideal ASML abide well with the results of the implemented sample, validating the proposed design principle. The presented acoustic magnifying lens has a wide spectrum of possible applications ranging from medical imaging, and biomedical sensors to focused ultrasound surgery.

scholarly journals Current Development and Applications of Super-Resolution Ultrasound Imaging

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2417
Author(s):  
Qiyang Chen ◽  
Hyeju Song ◽  
Jaesok Yu ◽  
Kang Kim
Keyword(s):  
Kidney Disease ◽  
Ultrasound Imaging ◽  
Atherosclerotic Plaque ◽  
Super Resolution ◽  
Emerging Technology ◽  
Diffraction Limit ◽  
Disease Models ◽  
Current Development ◽  
Future Directions ◽  
Acoustic Diffraction

Abnormal changes of the microvasculature are reported to be key evidence of the development of several critical diseases, including cancer, progressive kidney disease, and atherosclerotic plaque. Super-resolution ultrasound imaging is an emerging technology that can identify the microvasculature noninvasively, with unprecedented spatial resolution beyond the acoustic diffraction limit. Therefore, it is a promising approach for diagnosing and monitoring the development of diseases. In this review, we introduce current super-resolution ultrasound imaging approaches and their preclinical applications on different animals and disease models. Future directions and challenges to overcome for clinical translations are also discussed.

scholarly journals Frequency-Tunable Terahertz Plasmonic Structure Based on the Solid Immersed Method for Sensing

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1419
Author(s):  
Toshio Sugaya ◽  
Yukio Kawano
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Wavelength Region ◽  
Diffraction Limit ◽  
Field Analysis ◽  
Plasmonic Structure ◽  
Sensing Applications ◽  
Frequency Tunable ◽  
Bull's Eye

Terahertz waves are located in the frequency band between radio waves and light, and they are being considered for various applications as a light source. Generally, the use of light requires focusing; however, when a terahertz wave is irradiated onto a small detector or a small measurement sample, its wavelength, which is much longer than that of visible light, causes problems. The diffraction limit may make it impossible to focus the terahertz light down to the desired range by using common lenses. The Bull’s Eye structure, which is a plasmonic structure, is a promising tool for focusing the terahertz light beyond the diffraction limit and into the sub-wavelength region. By utilizing the surface plasmon propagation, the electric field intensity and transmission coefficient can be enhanced. In this study, we improved the electric field intensity and light focusing in a small region by adapting the solid immersion method (SIM) from our previous study, which had a frequency-tunable nonconcentric Bull’s Eye structure. Through electromagnetic field analysis, the electric field intensity was confirmed to be approximately 20 times higher than that of the case without the SIM, and the transmission measurements confirmed that the transmission through an aperture had a gap of 1/20 that of the wavelength. This fabricated device can be used in imaging and sensing applications because of the close contact between the transmission aperture and the measurement sample.

scholarly journals Improvement of an InfraRed Pyroelectric Detector Performances in THz Range Using the Terajet Effect

2021 ◽  
Vol 11 (15) ◽  
pp. 7011
Author(s):  
Oleg V. Minin ◽  
Jaime Calvo-Gallego ◽  
Yahya M. Meziani ◽  
Igor V. Minin
Keyword(s):  
Internal Structure ◽  
Diffraction Limit ◽  
Noise Equivalent Power ◽  
Pyroelectric Detector ◽  
Optical Window ◽  
Ir Sensors ◽  
Thz Detection ◽  
Thz Range ◽  
Thz Applications

An infrared (IR) pyroelectric detector was investigated for terahertz (THz) detection using the principle of the terajet effect, which focuses the beam beyond the diffraction limit. The terahertz beam was coupled to the detector’s optical window through a two-wavelength-dimension dielectric cubic particle-lens based on the terajet effect. We experimentally demonstrate an enhancement of about 6 dB in the sensitivity under excitation of 0.2 THz without degradation of the noise equivalent power value. The results show that the proposed method could be applied to increase the sensitivity of various commercial IR sensors for THz applications that do not require modification of the internal structure, and it may apply also to acoustics and plasmonic detectors.

scholarly journals Implementation of a superresolution far-field spot-generator with 1/5 the diffraction limit

2021 ◽  
Vol 3 ◽  
pp. 100067
Author(s):  
Praneeth Gadamsetti ◽  
Markus Testorf ◽  
David A. Gonzalez ◽  
Paolo Batoni ◽  
Menelaos K. Poutous
Keyword(s):  
Diffraction Limit ◽  
Far Field
Sign in / Sign up

Export Citation Format

Share Document