3D direct laser writing using a 405  nm diode laser.

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Three-dimensional (3D) direct laser writing typically employs near-infrared femtosecond lasers.
• A shift towards shorter wavelengths offers potential for improved resolution and reduced feature sizes.

Purpose of the Study:

• To investigate the feasibility of using a quasi-continuous wave (quasi-cw) blue diode laser (405 nm) for 3D direct laser writing.
• To identify suitable photoresist systems for nonlinear multiphoton polymerization at this wavelength.
• To evaluate the resolution enhancement and fabrication capabilities of this blue laser system.

Main Methods:

• Screening of photoresist systems for nonlinear multiphoton polymerization at 405 nm.
• Utilizing a high-numerical-aperture objective lens (NA=1.4) to achieve a diffraction-limited focus.
• Fabrication and characterization of 2D and 3D benchmark structures.
• Demonstration of dip-in direct laser writing.

Main Results:

• Identification of photoresists enabling nonlinear multiphoton polymerization with a 405 nm laser.
• Achieved diffraction-limited focusing essential for wavelength advantage.
• Fabricated benchmark structures demonstrating the potential for reduced linewidths and improved resolution.
• Successful implementation of dip-in direct laser writing.

Conclusions:

• A quasi-cw blue diode laser system is effective for 3D direct laser writing.
• This approach offers a viable alternative to traditional infrared systems, potentially enabling finer feature sizes.
• The developed method advances micro- and nanofabrication capabilities.