MEASUREMENT OF COMPLEX LINE SHAPES BY PHASE-LOCKED CAVITY RING-DOWN AND BUILDUP SPECTROSCOPY
Hodges, Joseph T.
- MEASUREMENT OF COMPLEX LINE SHAPES BY PHASE-LOCKED CAVITY RING-DOWN AND BUILDUP SPECTROSCOPY
- Hodges, Joseph T.
- Lisak, Daniel ; Gillis, Keith A.; Ciurylo, Roman ; Cygan, Agata ; Fleisher, Adam J.
- Issue Date
- Lineshapes, collisional effects
- Light propagation in a passively decaying optical resonator occurs exclusively at the cavity resonance frequencies because only these fields satisfy the source-free wave equation. This mechanism occurs regardless of the frequency spectrum of the light source. Likewise, after switching on a light source to build up power within a resonator, transient fields at the cavity resonance frequencies are induced which prevent the instantaneous buildup of intra-cavity circulating power. For the case of mode-matched excitation by a single-frequency laser, the transient response of the system involves fields at the incident laser frequency and the cavity resonance frequency. To illustrate, we show that a frequency-agile probe laser which maintains phase lock to an optical resonator during both decay and buildup events yields exponentially damped heterodyne beat signals between the incident laser field and the local cavity resonance. These signals have a damping rate equal to one half the conventional ring-down value and occur at the frequency difference of the source laser and resonance fields. This technique enables the simultaneous measurement of absorption (decay rate) and dispersion (mode shifting) associated with light-matter interaction in a ring-down cavity. We illustrate how these complementary data can be used to measure complex-valued line shapes and validate associated line profiles.
- International Symposium on Molecular Spectroscopy
- Type of Resource
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