The use of compact disc (CD) pickups in optical profilometry is a well-established practice. The instruments currently available on the market are, however, expensive both to purchase and to maintain. This expense is mainly due to the high cost of the scanning system, and it makes the use of low-cost pickups fruitless. Moreover, translation stages are bulky, slow, and in most applications neither necessary nor desirable. We present a one-dimensional profilometer, which uses a CD pickup as both the sensor and the actuator. Beam scanning of the sample is in fact performed by the objective lens tracking motor. The device is cheap, fast, compact, light, and a valuable solution for fluid and hard-to-access surface profiling.
We describe an interferometer that makes use of an optical pickup. This widespread consumer electronics component has a high degree of technological content. A typical head contains a remarkable, highly integrated sample of optoelectronic laboratory equipment. The application that we report is a significant and novel example of the potential exploitation of the unique features of such a device for scientific aims. Many interferometric configurations can be envisaged, depending on the specific pickup design. We present a Fizeau multiphase homodyne interferometer that makes use of an astigmatic-focus-detection pickup. Its quadrant detector provides four photocurrent signals whose phase delays can be easily controlled. This allows us to apply phase-shifting interferometry algorithms for data reduction.
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