Laguerre-Gauss beam generation in IR and UV by subwavelength surface-relief gratings

Abstract

The angular momentum of light can be described by the states of spin angular momentum, associated with polarization, and orbital angular momentum, related to the helical structure of the wave front. Laguerre-Gaussian beams carry orbital angular momentum and their generation can be done by using an optical device known as q-plate. However, due to the usage of liquid crystals, these components may be restricted to operate in specific wavelengths and low power sources. Here we present the fabrication and characterization of q-plates made without liquid crystals, using processes of electron beam lithography, atomic layer deposition and dry etch techniques. We exploit the phenomenon of form birefringence to give rise to the spin-to-orbital angular momentum conversion. We demonstrate that these plates can generate beams with high quality for the UV and IR range, allowing them to interact with high power laser sources or inside laser cavities.

Laser shaping and optical power limiting of pulsed Laguerre-Gaussian laser beams of high-order radial modes in fullerene C60

“…The ability to generate and shape optical beams with novel spatial-temporal structures has increased dramatically in state-of-the-art laser technology. [27][28][29] Laguerre-Gaussian (LG) laser beams, [30][31][32] as a class of optical field with cylindrical symmetry, have been well produced due to their promising applications in laser manufacturing, micromechanical manipulation, quantum optics, optical communication and so on. [33][34][35][36][37][38][39][40] Compared with the fundamental transverse mode Gaussian beam, the higher-order LG beams are beams with transverse spatial modes and may even carry photonic orbital angular momentum.…”

Fabrication of an Anti-Reflective Microstructure on ZnS by Femtosecond Laser Bessel Beams

“…It has the advantages of wide bandwidth, large angular response, high mechanical strength, and surface hydrophobicity [ 12 , 13 , 14 ]. The current ASS manufacturing technologies, such as machining [ 15 ], electron beam lithography [ 16 ], lithography [ 17 ], reactive ion lithography [ 18 ], interference lithography [ 19 ] and nanoimprint lithography [ 7 ], have the shortcomings of limited materials, complex procedures, low efficiency and inability to achieve curved parts processing. Femtosecond laser is a unique technology for fabricating subwavelength structures (SWMS), on account of its simplicity, mask-less, flexible machining of space, high processing accuracy and environmental friendliness [ 20 , 21 ].…”

Polarization-Dependent All-Dielectric Metasurface for Single-Shot Quantitative Phase Imaging

“…By engineering the waveguide properties, for example, by appropriate combination of the meta-atoms’ shape, size, and orientation, a 0–2π phase modulation can be realized. Owing to the subwavelength size and arrangement of the meta-atoms, metasurfaces circumvent the need for bulky components to achieve complex optical functionalities, which makes them conducive for compact integrated setups. , As such, metasurfaces have found applications for beam focusing, , deflection , holography, and optical vortex generation. , Interestingly, these functionalities can be introduced independently and simultaneously in different polarization components of the incident light using a single metasurface. , Further advancement has recently been reported in the arbitrary polarization control along the beam propagation direction with a metasurface . Tailored metasurfaces have also been shown to improve the imaging performance and facilitate super-resolution imaging and different contrast-enhancing modes in microscopy. − …”

“…5,6 As such, metasurfaces have found applications for beam focusing, 7,8 deflection 9,10 holography, 11 and optical vortex generation. 12,13 Interestingly, these functionalities can be introduced independently and simultaneously in different polarization components of the incident light using a single metasurface. 14,15 Further advancement has recently been reported in the arbitrary polarization control along the beam propagation direction with a metasurface.…”