Photonic nanojets with extended focusing length and narrowed beam waist by immersed engineered dielectric hemisphere

2021 ◽  
Author(s):  
Xianchao Liu ◽  
Xingchao Zhang ◽  
Jun Wang
Keyword(s):  
Beam Waist ◽  
Photonic Nanojets

scholarly journals Photonic nanojets with ultralong working distance and narrowed beam waist by immersed engineered dielectric hemisphere

2020 ◽  
Vol 28 (23) ◽  
pp. 33959
Author(s):  
Xianchao Liu ◽  
Hongxi Zhou ◽  
Ming Yang ◽  
Zheyuan Xie ◽  
Qi Han ◽  
...  
Keyword(s):  
Beam Waist ◽  
Photonic Nanojets ◽  
Working Distance

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

scholarly journals Molecular Monolayer Sensing Using Surface Plasmon Resonance and Angular Goos-Hänchen Shift

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4593
Author(s):  
Cherrie May Olaya ◽  
Norihiko Hayazawa ◽  
Maria Vanessa Balois-Oguchi ◽  
Nathaniel Hermosa ◽  
Takuo Tanaka
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Incident Beam ◽  
Expected Value ◽  
Beam Waist ◽  
Self Assembled Monolayer ◽  
Hydrophilic Nature ◽  
Small Change ◽  
Made In

We demonstrate potential molecular monolayer detection using measurements of surface plasmon resonance (SPR) and angular Goos-Hänchen (GH) shift. Here, the molecular monolayer of interest is a benzenethiol self-assembled monolayer (BT-SAM) adsorbed on a gold (Au) substrate. Excitation of surface plasmons enhanced the GH shift which was dominated by angular GH shift because we focused the incident beam to a small beam waist making spatial GH shift negligible. For measurements in ambient, the presence of BT-SAM on a Au substrate induces hydrophobicity which decreases the likelihood of contamination on the surface allowing for molecular monolayer sensing. This is in contrast to the hydrophilic nature of a clean Au surface that is highly susceptible to contamination. Since our measurements were made in ambient, larger SPR angle than the expected value was measured due to the contamination in the Au substrate. In contrast, the SPR angle was smaller when BT-SAM coated the Au substrate due to the minimization of contaminants brought about by Au surface modification. Detection of the molecular monolayer acounts for the small change in the SPR angle from the expected value.

scholarly journals Direct imaging of photonic nanojets

2008 ◽  
Vol 16 (10) ◽  
pp. 6930 ◽  
Author(s):  
Patrick Ferrand ◽  
Jérôme Wenger ◽  
Alexis Devilez ◽  
Martina Pianta ◽  
Brian Stout ◽  
...  
Keyword(s):  
Direct Imaging ◽  
Photonic Nanojets

Forward Scattering Signature of a Spherical Particle Crossing a Laser Beam out of the Beam Waist

1988 ◽  
Vol 5 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Jean-Philippe Chevaillier ◽  
Jean Fabre ◽  
Patrice Hamelin ◽  
Jean-Loup Lense
Keyword(s):  
Laser Beam ◽  
Spherical Particle ◽  
Beam Waist ◽  
Forward Scattering
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