Ring resonator
This picture shows lasing inside a goblet-shaped ring resonator doped with Pyrromethene 597 laser dye. The device is pumped using a 532-nm Nd:Yag laser and emits light at around 620 nm. The green corresponds to the pump beam and the red light to the lasing mode at the edges of the ring. The picture was taken from above using a self-built microscope with a color CCD camera.
—Ofer Bar-On Tel Aviv University, Israel