Abstract: A near-field optical head objective lens that can read and write high-density data on an optical disc is disclosed. On a surface where an incident beam converges by the near-field optical head objective lens, a film that can produce surface plasmon effect is coated. As the incident beam hits the material and produces the surface plasmon, a micro aperture is generated to minimize the diameter of the light spot, thereby increasing the data capacity stored in the optical disc.

Abstract: A near-field optical head objective lens that can read and write high-density data on an optical disc is disclosed. On a surface where an incident beam converges by the near-field optical head objective lens, a film that can produce surface plasmon effect is coated. As the incident beam hits the material and produces the surface plasmon, a micro aperture is generated to minimize the diameter of the light spot, thereby increasing the data capacity stored in the optical disc.

Abstract: This specification discloses an automatic calibration method for the output power of a pickup head for an optical information recording apparatus, which avoids laser diode thermal effects using duty cycle control and obtains the correct conversion function between the output current of a front monitor diode and the output power of the pickup head by curve fitting. This method only needs to measure one set of front monitor diode output current and output power conversion function of the pickup head. The same conversion function is applicable to all pickup heads of the same type. The optical information recording apparatus automatically detects the corresponding parameter for the pickup head. Each optical information recording apparatus can also automatically detect the specific power control parameters for each set of power control channel to obtain the optimal recording characteristics.