Numerical Optical Low-Coherence Holographic Microscopy

E. Cuche, P. Poscio, Ch. Depeursinge
1996 Biomedical Engineering  
The Oprical Low-Coherence Holographie Microscopy (OLCHM) is a three dimensional imaging method which mixes the concepts of low coherence holography and holographic microscopy. We present here a numerical application of this method that consists of recording a digital hologram on a CCD camera, the reconstmction of which is perfbrmed numerically by means of a Fast Fresnel Transform algorithm. The transverse resolution of the reconstructed images mainly depends on the resolution limit of the
more » ... components used («Ιμπι). As a consequence of the low coherence, the depth resolution is reduced to about 25 um. INTRODUCΉON: In conventional optical holography, the light intensity in the hologram plane Iy(x>y) is recorded on a photographic plate. After development, the hologram is illuminated with a wave identical to the reference and the transmitted wave front contains four terms: Ψ (*, y) = RR 2 + RO 2 + R 2 O* + R 2 O (1) Where O and R are the complex amplitudes of the object and reference waves respectively and O, R their modulus. The two first terms correspond to the zero order diffraction, the third term to the real image and the fourth to the twin image [1] . If the hologram has been recorded according to the Fresnel condition: 4^LV9~·»/ · vi ~jt i max (2) with λ the wavelength and d the distance between the hologram plane Oxy and the object plane Οξη, the transmitted wave front Ψ(ξ,ΐ]) can be calculated at a distance d from the hologram with the Fresnel-Kirchoff integral: Γ(/πΔξ,/ζΔη) = 6*/?
doi:10.1515/bmte.1996.41.s1.186 fatcat:3x32gd6hmbcd3aznaogfbgf3fa