Adjustment-free two-sided 3D direct laser writing for aligned micro-optics on both substrate sides

Area of Science:

• Optics and Photonics
• Materials Science
• Microfabrication

Background:

• 3D direct laser writing is a versatile technique for creating micro-optics.
• Existing methods include immersion mode and dip-in mode, each with limitations.
• Precise alignment and material combination are challenges in fabricating complex micro-optical systems.

Purpose of the Study:

• To demonstrate a novel hybrid printing approach for 3D direct laser writing.
• To achieve alignment-free fabrication of doublet objectives with integrated features.
• To enable the use of different photoresists on opposing sides of a substrate.

Main Methods:

• Combining dip-in and photoresist immersion printing techniques.
• Utilizing the photoresist itself as the immersion medium.
• Fabricating a doublet objective lens on the front and a black aperture on the back of a substrate.

Main Results:

• Achieved lateral registration below 1 µm for front and back side fabrication.
• Demonstrated alignment-free fabrication of doublet objectives and integrated apertures.
• Successfully combined different photoresists on the front and back surfaces.

Conclusions:

• The developed hybrid printing method offers a significant advancement in micro-optics fabrication.
• This technique simplifies the process and enhances precision for complex optical components.
• It opens new possibilities for integrated micro-optical systems with tailored functionalities.