Single-VIPA dual-mode absorption-emission spectroscopy for plasma diagnostics.

Combined absorption-emission spectroscopy is demonstrated using a single VIPA spectrometer coupled to a supercontinuum source. The system captures a ~36 nm bandwidth (742-778 nm) at picometer resolution. In a low-pressure glow discharge, N2 emission calibration, O I 777 nm triplet absorption (2.2% consistency), and linewidth analysis distinguishing instrumental/Doppler broadening from Ar I self-absorption (broadening factors up to ~1.5) are performed. Joint retrieval of temperature (953 ± 49 K) and instrumental width, along with time-division absorption-emission measurements, is demonstrated. Long-term stability makes this approach suitable for quasi-steady plasmas.