Self-Resonant Microlasers of Colloidal Quantum Wells Constructed by Direct Deep Patterning

Area of Science:

• Nanophotonics
• Materials Science

Background:

• Colloidal quantum wells (CQWs) offer tunable optical properties.
• Fabricating high-quality, on-chip micro-scale photonic devices from colloidal solutions remains challenging.

Purpose of the Study:

• To report the first self-resonant, fully colloidal micro-lasers (μ-lasers) based on colloidal quantum well (CQW) solutions.
• To develop a deep patterning technique for creating high aspect-ratio CQW resonators on-chip.

Main Methods:

• A deep patterning technique was developed to fabricate CQW resonators with grating waveguides and in-plane reflectors.
• The technique creates well-defined, closed-packed CQW layers with sharp edges and residue-free surfaces.
• The method was validated for various nanoparticles, including colloidal quantum dots and metal nanoparticles.

Main Results:

• Successfully fabricated waveguide-coupled lasers enabling tight optical confinement and in-plane lasing.
• Demonstrated that the patterning process preserves the pristine physical and chemical properties of immobilized nanocrystals (NCs).
• Achieved fabrication of NC patterns with subwavelength lateral features and micron-scale heights in high aspect ratios.

Conclusions:

• The developed deep patterning technique enables the creation of novel on-chip colloidal micro-lasers.
• This method is versatile and applicable to various nanomaterials, preserving their intrinsic properties.
• The technique opens possibilities for fabricating advanced nanophotonic devices with high aspect ratios.