A Millimetre-Wave Cuboid Solid Immersion Lens with Intensity-Enhanced Amplitude Mask Apodization

Abstract

Photonic jet is a narrow, highly intensive, weak-diverging beam propagating into a background medium, and can be produced by a cuboid solid immersion lens (SIL) in both transmission and reflection modes. Amplitude mask apodization is an optical method to further improve the spatial resolution of a SIL imaging system via reduction of waist size of photonic jet, but always leading to intensity-loss due to central masking of the incoming plane wave. In this letter, we report a particularly sized millimetre-wave cuboid SIL with the intensity-enhanced amplitude mask apodization for the first time. It is able to simultaneously deliver extra intensity enhancement and waist narrowing to the produced photonic jet. Both numerical simulation and experimental verification of the intensity-enhanced apodization effect are demonstrated using a copper-masked Teflon cuboid SIL with 22 mm side length under radiation of a plane wave with 8 mm wavelength. Peak intensity enhancement and the lateral resolution of the optical system increase by about 36.0 % and 36.4 % in this approach, respectively.

Apodization‐Assisted Subdiffraction Near‐Field Localization in 2D Phase Diffraction Grating

“…Interestingly, the partial apodization of DG steps leads not only to the narrowing of field localization region but in some cases can increase its intensity. In this sense, one can speak about the first realization of the anomalous apodization effect in a 2D binary diffractive structure similar to the anomalous apodization observed earlier in isolated 3D‐particles . Indeed, as seen in Figure a, in the range of pupil mask widths, , focal intensity begins to exceed the corresponding value in the non‐masked case (5).…”

“…At the same time, for a single 3D dielectric particle recent advances show the possibility for extreme field localization (resolution) improvement based on the embedding of apodization pupil mask into the illuminated particle surface . For example, the imaging resolution of about λ /3.24 was reported in ref.…”

“…In ref. [], it was reported that in some cases due to so‐called anomalous apodization effect, for cubic and column‐shaped pupil‐masked particles the sharp field focusing could be realized providing higher light intensity enhancement than that for isolated sphere. However, again the subwavelength field localization was not achieved.…”

Терагерцовый Микроскоп На Основе Эффекта Твердотельной Иммерсии Для Визуализации Биологических Тканей-=sup=-*-=/Sup=-

“…Так, в работах [19,20] достигнуто пространственное разрешение до 0.5λ, при этом использовались мезоразмерные частицы, изготовленные как из однородного материала, так и из метаматериалов с искусственно подобранными диэлектрическими свойствами [21]. Другим перспективным методом улучшения пространственного разрешения является эффект твердотельной иммерсии, связанный с сужением каустики электромагнитного пучка при ее формировании в свободном пространстве на небольшом расстоянии (меньше длины волны) позади диэлектрической среды с высоким показателем преломления [22]. Особого внимания заслуживает метод микроскопии на основе эффекта твердотельной иммерсии.…”

Sound focusing of a wavelength-scale gas-filled flat lens

“…Motivated by the wave nature of light and sound, the research in electromagnetic waves have been transferred to acoustic waves. The existence of an acoustic analogue to the photonic jet was demonstrated for the first time by Minin's [14,15] and they called the phenomenon "acoustojets". Underwater ultrasound has been chosen to confirm experimentally a high acoustic field localization in shadow area of a spherical Rexolite particle-lens with a diameter of 8.25 λ, where λ is the wavelength of the incident wave [16].…”