Laser expander design of highly efficient Blu-ray disc pickup head

Area of Science:

• Optics and Photonics
• Optical Engineering
• Materials Science

Background:

• Blu-ray Disc (BD) pickup heads utilize laser diodes for data reading and writing.
• The elliptical beam shape from laser diodes can limit the efficiency of optical pickup systems.
• Achieving a circular laser beam is crucial for optimizing BD system performance.

Purpose of the Study:

• To present an innovative collimator design for BD pickup heads.
• To enhance the efficiency of BD pickup head systems by transforming the laser diode beam shape.
• To explore and compare two distinct methods for implementing a horizontal beam expander.

Main Methods:

• The proposed design incorporates a horizontal beam expander.
• Two methods for constructing the beam expander are investigated: using two cylindrical lenses or two prisms.
• The design focuses on converting an elliptical laser diode beam into a circular one.

Main Results:

• The collimator design successfully transforms the laser diode beam from elliptical to circular.
• This beam shape conversion leads to higher efficiency within the pickup head system.
• Both cylindrical lens and prism-based beam expanders are viable approaches.

Conclusions:

• The developed collimator design with a horizontal beam expander offers a significant improvement in BD pickup head efficiency.
• The transformation to a circular beam is key to this enhanced performance.
• The study validates the effectiveness of both lens and prism-based beam expander configurations.