Refraction limit of miniaturized optical systems: a ball-lens example

Abstract

Abstract:We study experimentally and theoretically the electromagnetic field in amplitude and phase behind ball-lenses across a wide range of diameters, ranging from a millimeter scale down to a micrometer. Based on the observation, we study the transition between the refraction and diffraction regime. The former regime is dominated by observables for which it is sufficient to use a ray-optical picture for an explanation, e.g., a cusp catastrophe and caustics. A wave-optical picture, i.e. Mie theory, is required to explain the features, e.g., photonic nanojets, in the latter regime. The vanishing of the cusp catastrophe and the emergence of the photonic nanojet is here understood as the refraction limit. Three different criteria are used to identify the limit: focal length, spot size, and amount of crosspolarization generated in the scattering process. We identify at a wavelength of 642 nm and while considering ordinary glass as the ball-lens material, a diameter of approximately 10 µm as the refraction limit. With our study, we shed new light on the means necessary to describe micro-optical system. This is useful when designing optical devices for imaging or illumination.

Design and Fabrication of Microscale, Thin-Film Silicon Solid Immersion Lenses for Mid-Infrared Application

“…This shortened focal length in the SIL implies improved magnifying ability according to M1/F, where M is magnification, when the object distance smaller than the focal length. A schematic of an objective lens of a MIR-microscope system and a specimen substrate with µ-SIL shows that the image is enlarged by using µ-SIL as small as the wavelength with the focal length shorter than geometrical F paraxial , which has been mentioned in several previous articles for the visible wavelength range [5][6][7][8][9]16].…”

“…This shortened focal length in the SIL implies improved magnifying ability according to M∝1/F, where M is magnification, when the object distance smaller than the focal length. A schematic of an objective lens of a MIR-microscope system and a specimen substrate with µ-SIL shows that the image is enlarged by using µ-SIL as small as the wavelength with the focal length shorter than geometrical Fparaxial, which has been mentioned in several previous articles for the visible wavelength range [5][6][7][8][9]16]. To study the optical performance of a microlens in the MIR range depending on various parameters (e.g., the dimension, RoC, and refractive index of materials used), we performed a series of finite-difference time-domain (FDTD) electromagnetic wave propagation simulations by Fullwave (RSoft, Synopsys, Mountain View, CA, USA) simulation tool [17,18].…”

Ultra-broadband Asymmetric Light Transmission and Absorption Through The Use of Metal Free Multilayer Capped Dielectric Microsphere Resonator

“…The first scattering mechanism is dominant if the radius of the particle is much smaller than that of the incident light wavelength ( where k is light wave number) which is handled with the well-known ray optics or cusp catastrophe and caustics. The second one, however, appears in large particles where rigorous Mie theory should be applied to study the wave-optical nature where photonic nanojets studies rely 39 . In the case of Rayleigh scattering, when , the particle experiences a uniform E-field that is slowly oscillating in time and this incident E-field induces a time-varying Hertzian dipole moment in the sphere.…”

Geometric effect on photonic nanojet generated by dielectric microcylinders with non-cylindrical cross-sections

“…The optical resolution analysis for spherical, cylindrical, and non-cylindrical lens can be performed using anisotropic point-spread function. Future work will involve direct imaging of the interaction of photonic nanojet for the non-cylindrical micro-media with different profiles and polarizations of illuminations to obtain the super-resolution imaging [44,45]. 11.…”