Efficient tight focusing of laser beams optimally matched to their thin-film linear-to-radial polarization conversion: Method, implementation, and field near focus
| Autor: | Andrey G. Sedukhin, Alexander G. Poleshchuk |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
Diffraction business.industry Physics::Optics 02 engineering and technology Polarizer 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention 010309 optics Optical axis Axicon Wavelength Optics law 0103 physical sciences Radial polarization Electrical and Electronic Engineering Physical and Theoretical Chemistry 0210 nano-technology business Refractive index |
| Zdroj: | Optics Communications. 407:217-226 |
| ISSN: | 0030-4018 |
| DOI: | 10.1016/j.optcom.2017.09.042 |
| Popis: | A method is proposed for efficient, rotationally symmetric, tight mirror focusing of laser beams that is optimally matched to their thin-film linear-to-radial polarization conversion by a constant near-Brewster angle of incidence of the beams onto a polarizing element. Two optical systems and their modifications are considered that are based on this method and on the use of Toraldo filters. If focusing components of these systems operate in media with refractive indices equal to that of the focal region, they take the form of an axicon and an annular reflector generated by the revolution of an inclined parabola around the optical axis. Vectorial formulas for calculating the diffracted field near the focus of these systems are derived. Also presented are the results of designing a thin-film obliquely illuminated polarizer and a numerical simulation of deep UV laser beams generated by one of the systems and focused in an immersion liquid. The transverse and axial sizes of a needle longitudinally polarized field generated by the system with a simplest phase Toraldo filter were found to be 0.39 λ and 10.5 λ , with λ being the wavelength in the immersion liquid. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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