A generator of at least three continuous and phase-coherent laser beams at a first wavelength in the infrared domain and at a second and a third wavelength, respectively, of which one at least in the visible domain, the generator comprising: - an elementary source configured to emit a continuous laser beam at the first infrared wavelength; - an optical amplifier configured to amplify the continuous laser beam at the first wavelength; - a beamsplitter allowing, from the amplified laser beam, to generate first continuous laser beam at the first wavelength and a second continuous laser beam at the first wavelength, said first and second continuous laser beams at the first wavelength being phase-coherent; - a nonlinear frequency-doubling crystal, configured to generate, on the basis of the first continuous laser beam at the first wavelength, a continuous laser beam at the second wavelength, being phase-coherent with the first continuous laser beam at the first wavelength and therefore with the second continuous laser beam at the first wavelength, the first continuous laser beam at the first wavelength being directly coupled in the nonlinear frequency-doubling crystal; - a nonlinear frequency-sum-generating crystal, configured to generate, on the basis of the second continuous beam at the first wavelength and of the continuous laser beam at the second wavelength which are phase-coherent, a continuous laser beam at the third wavelength, being phase-coherent with the second continuous laser beam at the first wavelength and with the continuous laser beam at the second wavelength, the three generated continuous laser beams that are phase-coherent at the first, second and third wavelength respectively, arising all three from the amplified laser beam coming from the elementary source and comprising respectively: - the residual part of the second continuous laser beam at the first wavelength at the output of the nonlinear frequency-sum-generating crystal or a beam sampled at the output of the optical amplifier; - the residual part of the continuous laser beam at the second wavelength at the output of the nonlinear frequency-sum-generating crystal or a beam sampled at the output of the nonlinear frequency-doubling crystal; - the continuous laser beam at the third wavelength. - an elementary source configured to emit a continuous laser beam at the first infrared wavelength; - an optical amplifier configured to amplify the continuous laser beam at the first wavelength; - a beamsplitter allowing, from the amplified laser beam, to generate first continuous laser beam at the first wavelength and a second continuous laser beam at the first wavelength, said first and second continuous laser beams at the first wavelength being phase-coherent; - a nonlinear frequency-doubling crystal, configured to generate, on the basis of the first continuous laser beam at the first wavelength, a continuous laser beam at the second wavelength, being phase-coherent with the first continuous laser beam at the first wavelength and therefore with the second continuous laser beam at the first wavelength, the first continuous laser beam at the first wavelength being directly coupled in the nonlinear frequency-doubling crystal; - a nonlinear frequency-sum-generating crystal, configured to generate, on the basis of the second continuous beam at the first wavelength and of the continuous laser beam at the second wavelength which are phase-coherent, a continuous laser beam at the third wavelength, being phase-coherent with the second continuous laser beam at the first wavelength and with the continuous laser beam at the second wavelength, - the residual part of the second continuous laser beam at the first wavelength at the output of the nonlinear frequency-sum-generating crystal or a beam sampled at the output of the optical amplifier; - the residual part of the continuous laser beam at the second wavelength at the output of the nonlinear frequency-sum-generating crystal or a beam sampled at the output of the nonlinear frequency-doubling crystal; - the continuous laser beam at the third wavelength.