A four zone subwavelength binary diffraction optical micro element (size of 100x100 mkm) for polarization transformation from linear to radial was calculated and designed. A grating period was equal to 400 nm, a height of the element was equal to 110 nm in a gold film for a wavelength of 633 nm. Simulation by FDTD method and Rayleight-Zommerfeld integral shown, that despite only four zones used for polarization transformation to four different angles there are radial polarized light beam in the far field with smooth angle dependence on the beam circle observation position. Experimentally shown that in the near field, depending on the direction of the axis of the polarizer on the output light are two zones 4-zone trace element for one or the other diagonal, which proves the presence of radial polarization in the reflected beam.

Using a binary microlens of diameter 14 µm and focal length 532 nm (numerical aperture NA = 0.997), we focus a 633-nm laser beam composed of a mixture of radially and linearly polarized waves obtained by reflection of a linearly polarized Gaussian beam from a gold-coated subwavelength binary four-zone diffractive optical microelement (micropolarizer) of size 100×100 µm to a near-surface, near-circular focal spot of size (0.37±0.02)λ and (0.39±0.02)λ, where λ is wavelength. A linearly polarized light beam forms an elliptical focal spot with diameters (0.35±0.02)λ and (0.41±0.02)λ. Both focal spots have the area of 0.133λ². Subwavelength focusing using two microoptical components (a binary microlens and a micropolarizer) is suggested for the first time.

Описываются изготовление и исследование бинарной зонной пластинки из серебра на мембране из нитрида кремния с диаметром 200 мкм, крайней зоной 287 нм, глубиной релье­фа 460 нм, рассчитанной для длины волны 2,29 A с расчётной эффективностью около 3 %. Экспериментально c помощью матричного детектора с элементом разрешения 13×13 мкм было обнаружено, что в зоне Френеля возникает и устойчиво сохраняется на расстоянии 20 – 60 мм (фокусное расстояние – 250 мм) центральный максимум интенсивности, который на 6 % выше окружающего фона интенсивности.