Surface profilometry and low coherence interferometry by electronically controlled optical sampling

In optical sampling, a transient waveform under study is sampled with time delayed laser pulses, achieving a high time resolution. The limitations in measurement time due to the mechanical adjustment of the time delay can be overcome by asynchronous optical sampling (ASOPS) [1], where two pulsed lasers with slightly detuned repetition rates are employed. This technique is commonly used for studying transient characteristics [1], for infrared spectrometry [2] as well as remote sensing applications [3] and optical coherence tomography [4]. However, a static difference in repetition rates leads to static scanning ranges, resulting in unnecessary large measurement times and large amounts of measured data especially for the latter applications.