Modified method of direct laser writing radially symmetric structures

Предложен и промоделирован модифицированный метод прямой лазерной записи по фоторезисту. Метод основан на использовании плоскопараллельной пластины для смещения пишущего пучка. Проведено экспериментальное исследование по записи радиально-симметричных структур пучком со смещенной фокусировкой. A modified direct laser photoresist recording method was proposed and modeled. The method is based on using a planar-parallel plate to shift the writing beam. An experimental study was carried out on the recording of radially symmetric structures by a beam with a shifted focusing.Работа выполнена при поддержке Федерального агентства научных организаций (соглашение No 007-ГЗ/Ч3363/26), Министерства образования РФ в рамках выполнения государственного задания 3.3025.2017/4.6 и гранта Президента НШ-6307.2018.8

Transmitted moment of rotation in Bessel beams formed by different vortex axicons

Рассчитан орбитальный угловой момент (ОУМ) светового поля, который может быть передан вращаемому микрообъекту для пучков Бесселя с разным сочетанием топологических зарядов. Показано, что в большинстве случаев значение передаваемого микрообъекту ОУМ у аксиконов, рассчитанных методом сочетания топологических зарядов, больше, чем значение передаваемого микрообъекту ОУМ у аксиконов,сформированных бинарным винтовым аксиконом. The orbital angular momentum (OUM) of the light field, which can be transferred to a rotating micro-object for Bessel beams with a different combination of topological charges, is calculated. It is shown that in most cases the value of the orbital angular momentum transferred to the microobject for axicons, calculated by the combination of topological charges, is greater than the value of the orbital angular momentum transferred to the microobject for axicons formed by the binary vortex axicon

Optimization, fabrication and characterization of a binary subwavelength cylindrical terahertz lens

A problem of optimizing the subwavelength microrelief of a binary cylindrical transmissive diffractive lens (DL) with a 300-mm focal length for a wavelength of λ=141 μm was considered. High-resistivity silicon was chosen as the DL substrate material. The angle of incidence of the illuminating beam was taken to be π/6. The optimization parameters were the height of the DL profile and the fill factor of the groove. The main goal of optimizing the design was to increase the diffraction efficiency of the lens. The DL diffraction efficiency was calculated using a Fourier mod method. The DL was fabricated by plasma-chemical etching (Bosch process) of the surface of a silicon substrate. The diffraction efficiency of the calculated lens was estimated to be 70%. However, a full-scale experiment showed the real efficiency to be much lower. These differences are related to both errors in the manufacturing process of the DL and non-ideal thickness parameters of the silicon wafers