We developed distributedfeedback (DFB) resonators based on singleplasmon waveguides and firstorder lateral DFB (lDFB) gratings [Fig. 1(a)]. These lasers exhibit singlemode emission with output powers of a few mW at operating temperatures, which are accessible by compact Stirling coolers. Based on a rigorous solution of Maxwell’s equations for the DFB unit cell, we developed a general method to calculate the coupling coefficients of lDFB gratings. This allows for an efficient simulation of the resonator properties within the framework of the onedimensional coupledmode equations.
One goal for THz astronomy is the heterodyne spectroscopy of the neutral oxygen (OI) finestructure transition at 4.745 THz, which requires a local oscillator just a few GHz beside this transition frequency. Based on an optimized heterostructure and an adjusted lDFB grating, we achieved singlemode, cw operation around the target frequency [Fig. 1(b)].
1  Author  M. Wienold , A. Tahraoui , L. Schrottke , R. Sharma , X. Lü , K. Biermann , R. Hey , H.T. Grahn 
Title 
Lateral distributedfeedback gratings for singlemode, highpower terahertz quantumcascade lasers 

Source  Opt. Express , 20 , 11207 ( 2012 )  
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