Frequency-tunable laser source and method for emitting a frequency-tunable laser beam

Abstract

According to an aspect, the present description concerns a frequency-tunable laser source comprising: a set of N elementary sources (-), each elementary source being suitable for emitting a beam at a given central frequency (fk); an optical coupler () for coupling the beams emitted by each of the elementary sources in order to form a multi-spectral incident beam (B) regrouping all the frequencies of the N elementary sources in a same optical beam; a beam splitter () for forming, from the incident beam (B), a first beam (B) and a second beam (B), each regrouping all the frequencies of the elementary sources; a first tunable filter () for selecting, from the first beam (B), a third beam (B) at a first frequency (F); a second tunable filter () for selecting, from the second beam (B), a fourth beam (B) at a second frequency (F); a nonlinear frequency doubling crystal () for generating, from the third beam at the first frequency (F), a fifth beam (B) having a frequency (F) which is twice the first frequency; a nonlinear sum-frequency generation crystal () for generating, from the fifth beam coming from the nonlinear frequency doubling crystal and from the fourth beam at the second frequency (F), a beam (B) having a frequency (F) equal to the sum of twice the first frequency (F) and the second frequency (F).