Comparative study of various endoscopes for pulsed digital holographic interferometry

Area of Science:

• Optics and Photonics
• Interferometry
• Digital Holography

Background:

• Endoscopes are crucial for accessing confined spaces.
• Pulsed digital holography (PDH) offers high-speed, non-invasive imaging.
• Integrating endoscopes with PDH enables advanced metrology.

Purpose of the Study:

• To compare the performance of different endoscopes as image carriers in PDH.
• To evaluate the impact of endoscope spatial resolution on holographic interferometry quality.
• To explore potential applications of this combined technique.

Main Methods:

• Investigated three flexible multicore fiber endoscopes and one rigid endoscope.
• Integrated endoscopes into a PDH setup using a double-pulsed ruby laser.
• Employed an off-axis reference beam for quantitative phase difference measurements.
• Recorded digital holograms on a CCD camera.

Main Results:

• Endoscope spatial resolution directly correlates with the quality of phase maps from digital holographic interferometry.
• The setup successfully recorded phase differences with microsecond time separations.
• Demonstrated the feasibility of using endoscopes for PDH.

Conclusions:

• Endoscope selection is critical for achieving high-quality phase measurements in PDH.
• This technique shows promise for applications in challenging environments.
• Potential applications include medical endoscopy, micromechanics, and microelectronics.