We experimentally demonstrated lasing and anti-lasing at the same frequency in a single device.
Significance and Impact
Offers a new route for light modulation with extremely high contrast approaching the ultimate limit.
- Laser and anti-laser (or coherent perfect absorber) fundamentally contradict each other.
- By carefully engineering the loss (Cr/Ge) and gain (InGaAsP) materials to satisfy the parity-time symmetric condition, lasing and anti-lasing can both be attained in a single device.
- In-phase coherent amplification (due to lasing mode) and coherent absorption (due to anti-lasing mode) are experimentally observed at the same wavelength using a pump-probe measurement setup.