Bessel beam

About: Bessel beam is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 42264 citations.

Design and characterization of an axicon structured lens

Abstract: An axicon structured lens is designed and its properties of long focal depth is demonstrated. The phase function of the axicon structured lens is constructed according to the properties of nondiffractive Bessel beam with uniform-intensity. Based on the relationship of the side length of the square hole and the phase retardation, the required phase distribution of the axicon structured lens with a long focal depth in a metallic film can be determined. To verify the feasibility of the method, an axicon structured lens with focal length 1000 mm, a focal depth larger than 20 mm was designed and the intensity distribution of far field was calculated. The results show that the focal depth is 25 mm which is nearly 7 times extended with nearly diffraction-limited image quality. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3590723]

X-waves in self-focusing of ultra-short pulses

Abstract: X waves are emerging as a universal concept that allows us to interpret experiments of filamentation and trapping in a normally dispersive medium. We briefly review the main experimental and theoretical results behind this paradigm.

Acoustic Tweezers Based on Linear Fresnel Lens with Air Cavities for Large Volume Particle Trapping

Abstract: This paper reports a novel acoustic tweezers with multi-foci linear Fresnel lens that was designed to create a large Bessel beam zone for contactless, non-invasive object trapping in liquid. The tweezers was built on a 1-mm-thick lead zirconate titanate (PZT) substrate with rectangular air-cavity Fresnel lens having multiple focal lengths. With 25 V pp continuous 2.32 MHz sinusoidal drive, the acoustic tweezers is capable of trapping a silicon chip of $5.30\times 0.67\times 0.51\ \text{mm}^{3}$ in size and 3.98 mg in mass along with two $500-\mu\mathrm{m}$ -diameter Polyethylene microspheres.

Catenary-based phase change metasurfaces for mid-infrared switchable wavefront control

Abstract: Active wave manipulation by ultracompact meta-devices is highly embraced in recent years, but a major concern still exists due to the lack of functional reconfigurability. Moreover, the phase or amplitude discontinuities introduced by collective response of discrete meta-atoms make current meta-devices far from practical applications. Here, we demonstrate actively tunable wavefront control with high-efficiency by combining catenary-based meta-atoms for intrinsic continuous phase regulation with the chalcogenide phase change material (PCM) of Ge2Sb2Te5. First, switchable beam deflection is demonstrated in a wide mid-IR range between 8 μm and 9.5 μm with ‘on’ and ‘off’ states for beam steering between anomalous and normal specular reflections. Second, a switchable meta-axicon for zero order Bessel beam generation is demonstrated with full width at half maximum (FWHM) as small as ∼0.41 λ (λ = 12 µm). As a result, our scheme for active and continuous phase control potentially paves an avenue to construct active photonic devices especially for applications where large contrast ratio is highly desirable, such as optoelectronic integration, wavefront engineering and so on.