In optical interferometric metrology, the wavelength of light serves as a reference for length. At a given optical wavelength, an interference signal varies as a sinusoidal function of distance with a period equal to the wavelength. Although this approach offers unrivaled precision, the periodic signal results in a 2– ambiguity for measurement of lengths greater than one wavelength. In optical coherence tomography (OCT), one wishes to determine light scattering distances and distribution within a sample, but without the ambiguity. To accomplish this, OCT is based on interferometry using many optical wavelengths, each serving as a “ruler” with different periodicities. OCT traditionally has used broadband light sources providing a wide range of wavelengths, all simultaneously.Alternatively, a tunable light source emitting one wavelength at a time, rapidly swept over a broad spectral range, can also be used to achieve the absolute ranging capability in OCT. In this chapter, we describe a technical overview of these new emerging sources. We begin with a discussion general specifications of these light sources, the review basic fundamentals of laser and wavelength tuning. Finally, we discuss the principles of various techniques developed to date for high-speed and wide tuning range.
CITATION STYLE
Yun, S. H., & Bouma, B. E. (2015). Wavelength swept lasers. In Optical Coherence Tomography: Technology and Applications, Second Edition (pp. 619–637). Springer International Publishing. https://doi.org/10.1007/978-3-319-06419-2_21
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