Orbital angular momentum beam excitation through direct phase-matched coupling is experimentally demonstrated using an all-fiber weakly fused mode selective coupler consisting of a single-mode fiber and a ring-core fiber. Experimental results showing the excited OAM mode purity of up to 75% measured through the standard ring technique not only demonstrate the proof of concept but also provide a baseline for further improvement.
Stokes polarimetry measurements are carried out to calculate the spatial and angular Goos-Hänchen and Imbert-Fedorov shifts of a Gaussian beam reflected at glass-air interface, by measuring the phase difference between the TE and TM components and the amplitude of reflection. Variation of the beam shifts as a function of input beam polarization is also measured. The results obtained here are in good agreement with the theoretical predictions and the results obtained using a position sensitive detector. The polarimetric measurement method is accurate, independent of the intensity distribution of the beam, and opens up a new method to study the beam shift problem.
Self-healing, a counterintuitive but significant effect in structured light, that granting a light field the ability to reconstruct itself after a partial obstruction placed in its propagation path. Here, we will give a comprehensive review of the history and development of self-healing effects, especially highlighting its importance in vector vortex beams carrying spin and orbital angular momenta. Moreover, an unified zoology of self-healing, structured light is proposed to unveil a deeper understanding of its physical mechanism and provide a bird's eye view on diverse forms of self-healing effects of different kinds of complex structured light. Finally, we outline the open challenges we are facing, potential opportunities and future trends for both fundamental physics and applications.
We report the first demonstration of Raman amplification in a fiber of a single Bessel-like higher order mode using a multimode pump source. We amplify the LP-mode with a 559-µm effective mode area at a signal wavelength of 1115 nm in a pure-silica-core step-index fiber. A maximum of 18 dB average power gain is achieved in a 9-m long gain fiber, with output pulse energy of 115 µJ. The Raman pump source comprises a pulsed 1060 nm ytterbium-doped fiber amplifier with V-value ~30, which is matched to the Raman gain fiber. The pump depletion as averaged over the signal pulses reaches 36.7%. The conversion of power from the multimode pump into the signal mode demonstrates the potential for efficient brightness enhancement with low amplification-induced signal mode purity degradation.
We demonstrate an all-optical thermo-plasmonic effect to switch/modulate the surface plasmon resonance signal intensity excited at the metal-air interface. This optically addressed thermo-plasmonic measurement scheme is suitable to amplify very small changes in the complex dielectric constant (ε(m)(T)) of thin gold (Au) film, induced by the Ar(+) laser. The predominant contributions due to small but highly repeatable transient photo-thermal effects in the complex metal dielectric constant is confirmed to be the reason behind the highly reproducible all-optical thermo-plasmonic device performance presented here.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.