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), where two pulsed lasers with slightly detuned repetition rates are employed. This technique is commonly used for studying transient characteristics, for infrared spectrometry as well as remote sensing applications and optical coherence tomography. 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.