We present an optical technique for measuring irregularities on a small local surface (≈λ/100). This new technique uses a narrow laser beam as a local probe. The probe beam interferes with a reference beam. We use a 90° phase delay on the reference beam to increase the sensitivity. We show that if the test surface vibrates laterally, the collected power of the interferogram encodes as amplitude modulations, on a sinusoidal temporal carrier, the local surface irregularities.
© 1998 Optical Society of America
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.3940) Instrumentation, measurement, and metrology : Metrology
(120.4820) Instrumentation, measurement, and metrology : Optical systems
(240.6700) Optics at surfaces : Surfaces
Moisés Cywiak and Cristina Solano, "Reference-beam system for measuring relative small-surface local irregularities of a reflective object," Appl. Opt. 37, 1135-1139 (1998)