Figure 5: Dispersion measurements for the QCL at different drive currents and modulation conditions.
From: Homogeneous spectral spanning of terahertz semiconductor lasers with radio frequency modulation
Measured peak frequency (red circles) as a function of the mode number together with the linear fits (black lines). The right Y-axis shows the residuals from the measurements. Left column (a–c) are for free-running QCL at 700, 900 and 1100 mA, respectively, and right column (d–f) are for RF modulation at 700, 900 and 1100 mA, respectively. The green stars shown in (a–c) represent the missing peak frequency due to the strong water absorption at approximately 4.17 THz.
