A new optical front-end compensation technique for suppression of spurious signal in photoreflectance spectroscopy using an antiphase signal.
A new optical front-end compensation technique to suppress the unwanted, spurious signal in photoreflectance (PR) spectroscopy is developed. In this approach an optical compensation signal, which is amplitude-matched to and in antiphase to the spurious signal, is introduced and directed to the photodetector. The combination of the compensation signal and the spurious signal results in a dc output from the photodetector which is thereafter suppressed by the lock-in amplifier, leaving only the true PR signal to be recovered and amplified. A high spurious signal suppression efficiency is demonstrated and the advantages of the technique are discussed.
Li
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Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia. qing.li@anu.edu.au
Tan
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Jagadish
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