headeroct

High-Depth Optical Coherent Tomography (OCT)

In the last 25 years, Optical Coherence Tomography (OCT) has advanced to be one of the most innovative and most successful optical imaging techniques, reaching very high performance required for challenging applications like ophthalmic medicine, dermatology, angiography, and material analysis. OCT principle and domains The OCT technique is classically based on the principle of a Michelson interferometer, with a broadband light source as an input. The interferometric signature of this low coherence signal obtained with a Fourier Transform is a…

RamanOxxiusLaser

How to choose a laser for Raman Spectroscopy

In specific spectroscopy techniques like the Raman or LIBS (Laser-Induced Breakdown Spectroscopy) ones, the choice of the color and of the optical specifications of the excitation laser can be very important. The Raman spectrum of a material or a gas sample represents the energy shift of its vibration modes in relation to the laser excitation and is usually expressed in wavenumbers (cm-1 unit). In Raman spectroscopy, the effective radiated power varies as the excitation frequency to the fourth (due to the…

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Units conversion for spectrum representation

Wavelength, Wavenumber, Frequency and Photon Energy Conversion                                    The x-axis of a spectrum should be scaled in frequencies (in Hertz). The frequency representation is dedicated to applications such as measurements of atomic and molecular transitions, heterodyne spectroscopy or TeraHertz generation. The optical frequencies are so large (from 400 to 750 TeraHertz in the visible range) that it is common to use wavelengths in micrometers…