Determination of wavefront aberrations using a Fabry–Perot cavity

A new method for detecting wavefront aberrations using a Fabry–Perot cavity is described. A Fabry–Perot cavity transmits the cavity eigenmode which satisfies a resonance condition, while the other modes are reflected from the cavity. Utilizing this mode discrimination property, we can extract aberration components from incident aberrated light as reflected light from the cavity. Under the condition of a weak aberration, the amplitude profile of the reflected light can be approximated to the wavefront aberration. We can therefore determine the wavefront aberrations in a visualized form with the technique. We present the detection scheme and the first experimental verification of the technique. The detected aberration using this technique was in good agreement with the result on the basis of a conventional wavefront sensor.

Research highlights
► Detection of wavefront aberrations using a Fabry-Perot cavity.
► Light is mode-matched to the fundamental Gaussian mode of the cavity.
► Higher order modes are reflected from the cavity and detected visually.
► Coefficients for Zernike polynomials are calculated from the visualized pattern.
► Detected astigmatism coincides with results using a conventional method.