Bragg grating inscription in photosensitive materials by an optical replication process

Abstract

This paper examines the feasibility of producing multiplexed Bragg gratings for use as diffractive optical elements (DOEs) by coherent optical replication of a surface-relief phase grating into thick-film photosensitive materials. The use of such DOEs in light guide plates (LGPs) for optical imaging systems ensures energy-efficient light input into and output from LGPs and allows one to minimise their weight and size. We present simulation results for the interference structure fabrication process and recording of a series of multiplexed diffraction gratings in photosensitive materials.

Исследование Механизма Записи Мультиплексных Брэгговских Дифракционных Решеток С Планарным Вводом-Выводом Оптического Излучения В Стеклянных Световодах

“…Расчет самой фазовой маски основан на уравнении дифракции и базируется на периодах и углах наклона записываемой брэгговской решетки, которые необходимо реализовать. Скопированные брэгговские дифракционные решетки рассчитываем как волноводные голограммы для планарного ввода-вывода оптического излучения в стеклянных световодах [14]. Вводной H1 и выводной H2 элементы в пластине имеют одинаковую конфигурацию решеток, что можно интерпретировать как обратный ход работы выводного элемента по сравнению с вводным.…”

Investigation of the Recording Mechanism of Multiplex Bragg Gratings for Planar Optical Radiation Input/Output in Glass Lightguides

“…The calculation of the phase mask itself is based on the diffraction equation and uses the desired periods and tilt angles of the Bragg grating recorded, which must be implemented. The copied Bragg diffraction gratings are calculated as lightguide holograms for the planar input/output of optical radiation in glass lightguides [14]. The input (H1) and output (H2) components of the lightguide have the same configuration of gratings, which can be interpreted as a reverse operation of the output component compared to the input component.…”

Recording of the Multiplexed Bragg Diffraction Gratings for Waveguides Using Phase Mask

“…Single coherent beam illuminates the phase mask and forms superimposing beams in the diffraction orders, the phase mask gets replicated to the thick-layer holographic material. This method is also called holographic or optical replication [13,14], especially if the recording laser wavelength during the replication is the same as when recording the phase mask. Radiation with the wavelength of 0.325 µm (He-Cd laser 1) is expanded and collimated using lenses 2 и3 as a telescopic Kepler system.…”