Ultrasensitive Biosensing by a Plasmonic Nanolaser with a Record-Low Threshold at Room Temperature

Area of Science:

• Optics and Photonics
• Nanoscience
• Biotechnology

Background:

• Plasmonic nanolasers offer high energy density and narrow bandwidth for biosensing.
• High threshold values currently limit the widespread application of nanolasers.
• Low-loss plasmonic nanocavities are crucial for reducing nanolaser thresholds.

Purpose of the Study:

• To construct a plasmonic nanolaser with a record ultralow threshold.
• To demonstrate ultrasensitive DNA sensing in a biological environment using the developed nanolaser.
• To showcase the advantages of nanolasers for biosensing applications.

Main Methods:

• UV holographic lithography was used to fabricate optical nanocavities with high Q-factor and strong resonance intensity.
• LDS 751 dye was employed as the gain material.
• A commercial laser pointer served as the pumping source for nanolaser operation and DNA sensing.

Main Results:

• A plasmonic nanolaser with a record ultralow threshold of 0.49 mW/cm² at room temperature was successfully constructed.
• Ultrasensitive DNA sensing was achieved, with an ultralow detection limit of 1.91 nM for *Brucella* genetic detection in serum.
• The nanolaser demonstrated effective performance in a biological environment.

Conclusions:

• A universal strategy for constructing ultralow threshold nanolasers was provided.
• The study highlights the significant advantages of plasmonic nanolasers for ultrasensitive biosensing.
• This work paves the way for advanced nanolaser-based diagnostic tools.