Intense Bessel-like beams arising from pyramid-shaped microtips.

Area of Science:

• Optics and Photonics
• Microscopy
• Nanofabrication

Background:

• Generating highly focused and intense light beams is crucial for various scientific and technological applications.
• Conventional Bessel beams offer non-diffracting properties but can be limited in intensity enhancement.
• Micro- and nanostructured optical elements offer novel ways to control light propagation.

Purpose of the Study:

• To demonstrate the generation of intense, narrow, and low-divergence light beams using dielectric pyramid-shaped microtips.
• To characterize the properties of these beams and compare them with standard Bessel beams.
• To validate numerical simulations with experimental observations.

Main Methods:

• Fabrication of axicon-like dielectric pyramid microtips with submicrometric height using optical lithography and chemical etching.
• Numerical simulations to model light propagation through the microtip structures.
• Experimental imaging of the generated light beams using fluorescence microscopy.

Main Results:

• Intense, narrow, and low-divergence light beams are successfully produced at the apex of the microtips.
• The generated beams exhibit a Bessel transverse profile, narrower than conventional Bessel beams.
• Experimental results show remarkable agreement with numerical computations, confirming beam characteristics and intensity enhancement.

Conclusions:

• Dielectric pyramid-shaped microtips are effective in generating highly intense and narrow light beams.
• These novel beams offer significant light intensity enhancement compared to standard Bessel beams.
• The fabrication method is scalable and compatible with existing microfabrication techniques for integrated photonic devices.