Comparative study of various endoscopes for pulsed digital holographic interferometry

A comparison of several endoscopes as object image carriers in pulsed digit al holography is presented. Three multicore flexible fiber endoscopes of di fferent spatial resolution and one rigid endoscope are investigated. The fo ur endoscopes are integrated in a setup for the recording of digital hologr ams on a CCD camera. A double-pulsed ruby laser is used as the light source . A spatial carrier is introduced by an off-axis reference beam, which perm its quantitative evaluation of the phase difference between two holograms r ecorded with a short time separation (5-600 mus). From reported studies it may be inferred that the quality of the phase maps so derived. from digital holographic interferometry has a strong correlation to the spatial resolut ion of the multicore fiber used in these endoscopes. With the endoscopic te chnique combined with pulsed digital holography a number of useful applicat ions tin areas such as medical endoscopy, micromechanics, and microelectron ics) are envisaged for which access to the objects of interest is otherwise difficult. (C) 2001 Optical Society of America.