is known to be about 100 ms, [10, 11]. A semi-classical model of two-photon Raman transitions, induced by a femtosecond op- tical frequency comb in a three-level λ system, describes the cooling process of the internal degrees of freedom initiated in Feshbach molecules. Feshbach molecules can be created by association of ultracold atom pairs performed by magnetic field sweep across zero-energy resonance between the diatomic vibrational bound state and the threshold for dissociation into an atom pair at rest, [12]. They are the key intermediates in the process of creation of deeply bound molecules in the ground electronic configuration. A frequency comb known to be characterized by two key parameters, the radio-frequency f$_{r}$ , determined by the pulse repetition rate and specifying the spacing between modes, and by the carrier-envelop-offset frequency f 0 = f$_{r}$ Δ φ$_{ce}$/ (2 π ), here Δ φ$_{ce}$ is the carrier-envelope phase. Both parameters, the f 0 and the f$_{r}$ , were efficiently used to manipulate dynamics in, e.g., [6], to resonantly enhance two photon transitions in cold $^{87}$Rb atoms. Here, the control scheme is simplified by not involving f 0 . We make f 0 equal to zero by implying zero carrier-envelope phase in each pulse in the pulse train. The beam of a cw ring dye laser, having a sinusoidal modulation at the MHz frequency, was implemented in [13] to study absorption resonances in I 2 with high precision. Following the idea of sin-phase modulation, we create a femtosecond pulse train, having the sinusoidal modulation at THz frequency across an individual pulse, aiming to induce two-photon Ra- man transitions. The general form of the pulse train reads Here k is an integer number and T is the period of the pulse train. T is chosen to be much greater than a single pulse duration in order for the wings of each pulse to reduce to zero before next pulse arrives. The time-dependent phase across each pulse in the form of the sin function enriches the frequency comb spectrum with new peaks compared to a standard frequency comb. More specifically, laser frequency ω$_{L}$ determines the center of the frequency comb, while sinusoidal modulation forms the sidebands at multiples of Ω with the amplitude dictated by Φ 0 . The fine structure of the optical broadband comb is owing to the modes equally spaced by the radio frequency 2 πT − $^{1}$. We apply a single, sin-phase modulated optical frequency comb to induce Raman resonances in the three-level λ -system aiming full population transfer from the initial state | 1 > through intermediate state | 2 > 3 E ( t, z ) = Σ N$_{−}$ 1 k =0 E 0 exp( − ( t − kT ) $^{2}$/ (2 τ $^{2}$)) cos ( ω$_{L}$ ( t − kT ) + Φ 0 sin(Ω( t − kT ))) . (1)