Moments of the intensity of a single-mode laser driven by coloured pump noises with a cross-correlation between the real and imaginary parts of the quantum noise
Zhang Li, Cao Li, Wu Da-Jin
By means of the unified coloured noise approximation and phase lock, we study in this paper the stationary intensity distribution of the single-mode laser cubic model driven by coloured pump noise with cross-correlation between the real and imaginary parts of the quantum noise. We present a thorough discussion of how the cross-correlation λ q between the real and imaginary parts of the quantum noise and the self-correlation time τ of the pump noise determine the behaviours of the mean intensity ⟨ I ⟩ and variance λ 2 (0) for both below and above the threshold operation and many new phenomena are discovered. When the laser is operated above the threshold, increasing the cross-correlation intensity λ q makes the ⟨ I ⟩–τ curves exhibit a ``re-entrant phase transition''. Whether the laser is above or below the threshold, the whole ⟨ I ⟩–τ curve moves down as λ q increases; however, when λ q = 1 (perfect cross-correlation), the curve abruptly runs up. A nonzero value of cross-correlation time τ (τ≠0) leads to the entire λ 2 (0)– p ′ curve being suppressed (here p ′ is the pump noise intensity). This indicates the increasing precision of the laser beam due to the existence of the self-correlation time τ. The behaviour of the λ 2 (0)– p ′ curve as a function of λ q is similar to that of the ⟨ I ⟩–τ curve against λ q : that is, whether the laser is above or below the threshold, the λ 2 (0)– p ′ curve moves up as λ q increases; however, when λ q = 1, the curve suddenly moves down. Through the study in this paper, we can find a way to optimize for output laser intensity.
Chinese Physics•Feb 23, 2004•8 citations