Telescopes and microscopes have a lens {magnifying lens}| that enlarges images.
Telescopes and microscopes have a light-gathering lens {objective lens}|.
Telescopes and microscopes have a lens {ocular}| near eye for magnifying.
Thin fused silica, glass, or plastic rods {optical fiber}| can transmit light. Outside layer {cladding} reflects rays. Absorbing high-angle rays and reflecting low-angle rays makes one axial light ray. Refocusing light by refractive-index gradient makes one axial light ray. Wavelengths amplify in region with rare-earth erbium ions added, which laser excites. Over 150 wavelengths can be in fibers using multiplexing {dense wavelength division multiplexing} (DWDM), which allows 400 gigabits per second.
Blocks {superlens}| {metamaterial} can have thin wires in parallel planes {split-ring resonators} (SRR) a short distance apart, which have negative electrical permittivity and negative magnetic permeability and so negative refractive index. Forces from arrays push back on photons. Negative refractive index makes receding object blue-shifted. Cerenkov radiation travels in opposite direction, not forward. Refraction at boundary from positive to negative refraction bends light more, so it bends past perpendicular.
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Date Modified: 2022.0225