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Generation of squeezed light vacuum enabled by coherent population trapping
Optics Express
|April 6, 2021
Summary
Researchers generated squeezed vacuum states of light using resonant four-wave mixing (FWM) in helium. Spontaneous emission significantly influences squeezing, as confirmed by a model aligning with experimental data.
Area of Science:
- Quantum optics
- Atomic physics
Background:
- Four-wave mixing (FWM) is typically performed far from atomic resonance.
- Coherent population trapping (CPT) is a quantum interference effect.
Purpose of the Study:
- To demonstrate squeezed vacuum state generation via FWM-enhanced CPT.
- To investigate the influence of spontaneous emission on squeezed states.
Main Methods:
- Utilized a metastable helium cell at room temperature.
- Employed resonant FWM at an atomic transition.
- Developed a theoretical model incorporating absorption and spontaneous emission.
Main Results:
- Successfully generated squeezed vacuum states of light.
- Observed noise variances not solely explained by losses.
- Spontaneous emission was shown to contribute to squeezing within the cell.
Conclusions:
- Resonant FWM-enhanced CPT is a viable method for generating squeezed vacuum states.
- Spontaneous emission plays a crucial role in the observed squeezing.
- The theoretical model accurately predicts experimental outcomes without adjustable parameters.
