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Micro-optics are optical systems that are between a few micrometres and a millimetre in size. This includes small lenses or arrays of lenses, or optical fibres with a microscale core diameter. Such small optical components are important for integrated optics.
Uncompromised performance of micro-optical compound lenses has been achieved by high-fidelity shape definition during two-photon absorption microfabrication. The lenses have been made directly onto image sensors and even onto the tip of an optic fibre.
Mechanical oscillation in a microtoroidal optical cavity transfers chaos from a pump to a probe laser beam with a different wavelength. Through stochastic resonance, the combination of noise and internal chaotic dynamics leads to amplification of optomechanically induced light self-oscillations.
Without a well-defined cavity, there is no obvious way to control the resonant modes in a random laser. Experiments now show that shaping the optical pump allows for controlled single-mode operation at predetermined lasing wavelengths.