Wedge plate interferometry: a new dual field configuration for collimation testing

Collimation testing using wedge plate lateral shearing interferometry and Fourier fringe analysis

“…The authors reported an accuracy of 73 mm for a lens of focal length 250 mm. Later, Darlin et al [15] reported a dual field configuration using a combination of wedge plate and a prism retroreflector for collimation testing. Improvement in design, in terms of optical power consumed for testing purpose, is low.…”

Noncontact thickness measurement of plane-parallel transparent plates with a lateral shearing interferometer

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15] A transparent, parallel, or slightly wedged plate held obliquely to an incident beam works as an LSI. A wedged-plate LSI is more sensitive compared to a plane-parallel plate shearing interferometer because the shear fringes tend to align parallel to the shear direction with the increase in degree of collimation of the beam.…”

“…Techniques showing higher sensitivity in the testing of collimation have been reported. [4][5][6][7][8][9][10] Noncontact thickness measurement of transparent plates has been reported by researchers. 16,17 Their techniques require not only a sensitive detector but also a very high precision translation stage.…”