Adaptive Optics & Interferometry: Foundations

An adaptive-optics system uses a reference source, wavefront sensor, high-speed control computer, and deformable mirror. An interferometer combines light or radio signals from multiple telescopes with accurately known delays and baselines.

Adaptive optics measures wavefront errors many times per second and reshapes a mirror to apply the opposite distortion. Interferometry preserves phase information so signals from separated antennas or telescopes interfere coherently, encoding source structure at angular scales set by wavelength divided by baseline.

Corrected images show narrower point-spread functions and higher Strehl ratios than uncorrected images. Interferometers such as the Very Large Array and ALMA reconstruct images from many baseline measurements and achieve resolution far beyond one dish of comparable diameter.

Adaptive optics and interferometry both exploit wave information rather than treating a telescope only as a light bucket. Adaptive optics corrects atmospheric phase distortion in real time, while interferometry combines measurements from separated apertures to recover angular information corresponding to a much larger baseline. They address different limitations: one restores a single aperture toward its diffraction limit; the other synthesizes resolution beyond one telescope's diameter.