Tilted-reference-beam lateral shearing interferometer utilizing carrier-frequency photography

Area of Science:

• Optics and Photonics
• Interferometry
• Phase Contrast Imaging

Background:

• Carrier-frequency photography is a technique for visualizing phase objects.
• Traditional interferometry often requires complex setups, such as those using a tilted reference beam.

Purpose of the Study:

• To present a method using double-exposure carrier-frequency photography for phase object observation.
• To demonstrate the ability to distinguish positive and negative phase gradients.
• To explore alternative ways to generate the grating image in carrier-frequency photography.

Main Methods:

• Utilizing double-exposure photography with a rotated grating between exposures.
• Analyzing the resulting interferogram.
• Investigating image formation using an imaging lens versus the self-imaging property of the grating.

Main Results:

• The generated interferogram is comparable to those from interferometers with a tilted reference beam.
• The technique successfully differentiates between positive and negative phase variations.
• Both imaging lenses and grating self-imaging can produce the necessary grating image.

Conclusions:

• Double-exposure carrier-frequency photography with grating rotation is an effective method for phase object observation.
• This technique offers an alternative to traditional interferometric methods for phase gradient analysis.
• The flexibility in grating image formation enhances the applicability of carrier-frequency photography.