Threshold gain properties of lasing modes in ID disordered media optically pumped by femtosecond-lasing pulse

doi:10.1007/s12200-011-0213-2

Front Optoelec Chin

2011, Vol. 4

Issue (4) : 387-392 https://doi.org/10.1007/s12200-011-0213-2

RESEARCH ARTICLE

Threshold gain properties of lasing modes in ID disordered media optically pumped by femtosecond-lasing pulse

Yong LIU^1,2, Jinsong LIU¹(

)

1. Wuhan National Laboratory for Optoelectronics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; 2. Department of Physics and Electronics, Hubei University of Education, Wuhan 430205, China

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Abstract

By numerically solving Maxwell’s equations and rate equations, a comprehensive calculation on spectrum intensity and spectral widths of three localized modes via different pumping rates in one-dimensional (1D) disordered medium is investigated, in which pumping rate is described by a time function with duration of 80 fs. The spectral intensities varying with the peak value of femtosecond (fs) pumping pulse are calculated in the same disordered medium, and the calculated spectral intensities are compared with those with fixed pumping (simulation time is 6 ps). These results show that excited modes with fs pulse pumping rates are only slightly different from those with fixed pumping (picosecond (ps) pulse), which suggests the excited modes largely depend on the medium rather than the pumping rate at least for those of which pumping rates are fs and ps. At last, lifetimes of three excited modes are calculated. It is found that there is a certain corresponding relation between the mode’s lifetime and its threshold-pumping rate, which is the longer lifetime with lower threshold.

Keywords one-dimensional (1D) disordered medium lasing pumping rates localized modes

Corresponding Author(s): LIU Jinsong,Email:jsliu4508@vip.sina.com

Issue Date: 05 December 2011

Cite this article:

Yong LIU,Jinsong LIU. Threshold gain properties of lasing modes in ID disordered media optically pumped by femtosecond-lasing pulse[J]. Front Optoelec Chin, 2011, 4(4): 387-392.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-011-0213-2
https://academic.hep.com.cn/foe/EN/Y2011/V4/I4/387

Fig.1 Schematic illustration of 1D random medium

Fig.2 Illustration of pumping process with time

Fig.3 Intensity spectrum in arbitrary units versus the wavelength for 1D disordered medium shown in Fig. 1 at (a) = 1×10 s; (b) = 1×10 s; (c) = 1×10 s; (d) = 1×10 s; (e) = 1×10 s;(f) = 1×10 s

Fig.4 Plots of the peak intensity and spectral width of the lasing modes versus the pump rate under fs pulse pumping. (a) Peak intensities for the four indicated modes, and the lasing threshold measured from the plots are = 5×10 s, =3×10 s and =1.2×10 s; (b) peak intensity and spectral width for the mode

Fig.5 Spectral intensity in arbitrary units versus the wavelength for 1D disordered medium pumped by a fixed pumping rate shown in Fig. 1 at (a) = 1×10 s; (b) = 1×10 s; (c) = 1×10 s; (d) = 1×10 s

Fig.6 Normalized total energy decays with time for each marked mode. Three lifetimes are =2.84 ps, =0.92 ps, and =1.85 ps

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