Đang chuẩn bị liên kết để tải về tài liệu:
Optimization of trio-cavity raman laser pumped by pulsed gaussian beam

In this paper the set of dimensionless rate equations for the pump, Stokes and antiStokes powers in the trio-cavity Raman laser pumped by pulsed Gaussian beam is introduced. By numerical Runger-Kuta method, those equations are resolved and the optimal normalized parameters for enhancing the output powers are found out. | Communications in Physics, Vol. 22, No. 4 (2012), pp. 343-347 OPTIMIZATION OF TRIO-CAVITY RAMAN LASER PUMPED BY PULSED GAUSSIAN BEAM DINH XUAN KHOA AND CHU VAN LANH Vinh University Abstract. In this paper the set of dimensionless rate equations for the pump, Stokes and antiStokes powers in the trio-cavity Raman laser pumped by pulsed Gaussian beam is introduced. By numerical Runger-Kuta method, those equations are resolved and the optimal normalized parameters for enhancing the output powers are found out. I. INTRODUCTION Among the last previous works the CW Raman laser is the most interested [1–9]. The investigation for Raman lasers operating in pulse regime or pumped by pulse is still too little [10], specially, for Raman laser generating at anti-Stokes wave. To make rich knowledge of Raman laser, in this paper we introduce a set of dimensionless rate equations to describe revolution of intra-cavity powers (in Sec. 2), which is used to find out the optimal principle parameters of laser pumped by pulsed Gaussian pulse to enhance the output power of anti-Stokes wave (in Sec. 3). II. DIMENSIONLESS RATE EQUATIONS WITH GAUSSIAN PULSE Consider a Raman laser operating in trio-cavity resonator, which is illustrated in Fig.1 and pumped by an external Gaussian pulse given by [11]: !2 r √ W ln 2 ln 2t , Pep (t) = exp − (1) τ π τ where W and τ are the total energy and duration of the Gaussian pulse, respectively. Now, we make symbolization as follows: γp ≈ γs = ξloss1 γa = ξloss2 γep = γ; Pp W Ps W Pa W = Y1 ; = Y2 ; = Y3 ; τ τ τ kp + ks 8ωp µ0 = Qsa ; G(δ) π = Q; kp + ka ωs b Qkp Qsa ωa QW ωs QW kp ωs = α1 ; = α2 ; = α3 ; ks γτ ks γτ γτ QCW ωs Qξsa W ωa QCW ωa = α4 ; = α5 ; = α6 , γτ γτ γτ (2) x = t/γ; (3) 344 OPTIMIZATION OF TRIO-CAVITY RAMAN LASER PUMPED BY PULSED GAUSSIAN BEAM where ξloss1 and ξloss2 are defined as the ratio of Stokes wave loss to that of anti-Stokes p wave one and of Stokes wave to that of external wave one, respectively, γq = (c/nq .