Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 081302 |
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<mark>Journal publication date</mark> | 3/02/2012 |
<mark>Journal</mark> | Physical review B |
Issue number | 8 |
Volume | 85 |
Number of pages | 4 |
Publication Status | Published |
<mark>Original language</mark> | English |
We map out the band structure of a one-dimensional photonic crystal while a 12-fs control pulse activates ultrastrong interaction with quantized electronic transitions in semiconductor quantum wells. Phase-locked multi-terahertz transients trace the buildup of a large vacuum Rabi splitting and an unexpected asymmetric formation of the upper and lower polariton bands. The pronounced flattening of the photonic bands causes a slow-down of the group velocity by one order of magnitude on the time scale of the oscillation period of light.