Sub-Doppler resolution limited Lamb-dip spectroscopy of NO with a quantum cascade distributed feedback laser

Abstract

A quantum cascade distributed feedback laser operating at 5.2 microm is used to obtain sub-Doppler resolution limited saturation features in a Lamb-dip experiment on the R(13.5)1/2 and R(13.5)3/2 transitions of NO. The dips appear as transmission spikes with full widths of ~ 4.3 MHz. At this resolution the 73 MHz _-doubling of the R(13.5)3/2 line, which is normally obscured by the 130 MHz Doppler broadening, is easily resolved.

Sub-Doppler spectra of infrared hyperfine transitions of nitric oxide using a pulse modulated quantum cascade laser: Rapid passage, free induction decay, and the ac Stark effect

“…However, in our pump-probe spectra we have seen evidence for both sub-Doppler resolution of the − doublets and partial resolution of the hyperfine splitting pattern. 15 A previous Lamb-dip experiment using a QC laser carried out by Remillard et al 16 did achieve sub-Doppler resolution of the 2 3/2 R(10.5) and the 2 1/2 R(10.5), 2 3/2 transitions in a standing wave experiment, but could not resolve the hyperfine structure.…”

Supersonic free-jet quantum cascade laser measurements of ν4 for CF335Cl and CF337Cl and FTS measurements from 400 to 1260cm−1

“…Well designed distributed feedback (DFB) quantum cascade lasers (QCL) are considered excellent sources for precision IR spectroscopy, [1] for sub-Doppler techniques using saturated absorption, [2,3] as ultra-narrow stabilized sources for cavity-enhanced quantum optics applications such as NICE-OHMS [4], and for infrared based free space communications (FSC). This latter application, which has been of great interest to those interested in secure communication, typically requires the use of on-off keying (OOK) amplitude modulation techniques.…”

Quantum Cascade Laser Absorption Spectroscopy as a Plasma Diagnostic Tool: An Overview

“…Although saturated absorption spectroscopy has so far mainly been applied in the field of frequency metrology [91,92] as a Doppler-free method, it could be used to obtain localized concentration information from plasmas. It has been shown [93] and partly discussed in this paper that the output power levels of QCLs are sufficiently high to obtain power saturation.…”