Figure 2
From: Absolute spectroscopy near 7.8 μm with a comb-locked extended-cavity quantum-cascade-laser
Color code: green (free running), blue (slow locking), red (fast locking). (a) Beat note signal spectrum acquired with a sweep time of 6 ms at a 50 kHz resolution bandwidth, showing a nearly 20 MHz large laser jittering window at a ms time scale. (b) Averaged electrical spectrum of the beat note signal under slow and fast locking, as compared to the diffraction efficiency response of the AOFS (grey dashed dotted line). (c) Power spectral density of the error signal. (d) Scope traces of the laser intensity in locking condition.
