![]() There are a lot of extraction methods adopted in the CRD technique, including the nonlinear least square fitting (NLSF) algorithm such as the Levenberg–Marquardt (LM) algorithm, the weighted least square (WLS) method, and the extractions based on Fourier transform (FT) or linear regression of sum (LRS) of the decay signal, etc. For the accurate δ is essential for the calculation of weak absorption or high reflectivity, it is nontrivial to ensure the accuracy of extracted cavity decay time. Where L corresponds to the cavity length, which can be measured directly, c is the speed of light, α ( λ ) is the optical loss caused by weak absorption, R m ( λ ) is the reflectivity of the m -th cavity mirror, and γ corresponds to other losses that result from diffraction or scattering, etc. Here, A is the initial amplitude, offset refers to the combination of background noise and instrumental offset, and τ is the cavity decay time which has a relationship with RDC round-trip loss δ, as indicated as follows: After the laser pulse is injected or the continuous wave is suddenly shut off, the intensity of the output optical signal of RDC, I, will decay exponentially with time t, The laser beam, pulsed or continuous, is firstly coupled into a ring-down cavity (RDC). ![]() The cavity ring-down (CRD) technique is a sensitive detection technique for measuring weak absorption or high reflectivity.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |