Incoherent digital holographic adaptive optics
Published in Applied Optics, Vol. 52 Issue 1, pp.A117-A130 (2013)
Spotlight summary: Fresnel incoherent digital holography is a recent development in the ever-expanding area of digital holography. While holographic imaging is usually associated with spatially coherent illumination such as laser light, incoherent holographic imaging allows the use of spatially incoherent narrowband light sources such as LEDs. The main idea is to use a common path interferometer where the resultant recorded image is a sum of individual interference patterns from mutually incoherent point sources in the object of interest. By use of a Spatial Light Modulator (SLM) in the common path interferometer configuration, multiple phase-shifted versions of this sum total interference pattern may be recorded and numerically processed to obtain a 3D image of the incoherently illuminated object.
The paper by M. K. Kim explores the application of a suitably modified incoherent digital holography setup to adaptive optical systems. Adaptive Optics (AO) refers to real-time sensing and correcting of a wavefront for applications involving imaging through randomly fluctuating media (e.g. astronomical imaging through turbulent atmosphere). Ground based telescopes using AO correction are now capable of obtaining high quality astronomical images. The typical AO system consists of a Shack-Harmann wavefront sensor and a multi-element deformable mirror for wavefront correction. AO system implementation has many engineering challenges – particularly due to the near real time wavefront correction requirements. The incoherent digital holographic adaptive optics (IDAHO) concept discussed in this paper provides an interesting alternative to the traditional AO systems. The paper provides a framework for describing an incoherent digital holography system in the presence of aberrations and the subsequent aberration correction. The IDHAO system is then evaluated in terms of resolution, aberration type/strength, and noise. Simulations and experiments are shown for both point like and extended objects. An IDHAO system is likely to be a low cost leaner system compared to traditional AO systems with potentially similar wavefront correction and imaging performance.
|OCIS Codes:||(350.1260) Other areas of optics : Astronomical optics|
|(090.1995) Holography : Digital holography|
|(110.1080) Imaging systems : Active or adaptive optics|
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