| 摘要 |
A surface-emitting laser according to the present invention includes a laminated body between a first electrode 471 and a second electrode 472. The laminated body includes an active layer 43 and a two-dimensional photonic crystal 45. The first electrode 471 is ring shaped. A voltage is applied between the first and second electrodes 471 and 472 to supply an electric current into the active layer 43 and thereby cause an emission of light. Since the first electrode 471 is ring shaped, the light thereby generated has a ring-shaped field distribution within the two-dimensional photonic crystal 45. Due to this field distribution, a radially polarized laser beam having a ring-shaped cross section is emitted from the two-dimensional photonic crystal 45. The laser beam thus generated can be focused by a focusing lens to make its diameter smaller than the diffraction limit. Such a laser beam is suitable for optical pickups and other optical devices.
|
