White Laser Realized via Synergic Second- and Third-Order Nonlinearities.

Area of Science:

• Nonlinear optics
• Photonics
• Laser physics

Background:

• Broadband white lasers are crucial for diverse scientific applications.
• Existing methods face limitations in achieving balanced performance across key parameters.
• High-power, tunable white light sources are in demand.

Purpose of the Study:

• To report a novel scheme for generating a visible to near-infrared (vis-NIR) supercontinuum white laser.
• To harness the combined effects of second-order nonlinearity (2nd-NL) and third-order nonlinearity (3rd-NL) in a single nonlinear photonic crystal.
• To achieve efficient and tunable white laser output.

Main Methods:

• Utilized a chirped periodically poled lithium niobate (CPPLN) nonlinear photonic crystal.
• Employed a high-peak-power near-infrared (NIR) femtosecond pump laser (~1400 nm).
• Exploited quasiphase matching for simultaneous second-harmonic generation (SHG) and third-harmonic generation (THG).

Main Results:

• Successfully generated a bright vis-NIR (400-900 nm) supercontinuum white laser.
• Achieved high conversion efficiency up to 30% by synergistically combining 2nd-NL and 3rd-NL.
• Demonstrated wide tunability of the output white laser's spectral profile and chroma by adjusting pump parameters.

Conclusions:

• The proposed scheme effectively utilizes the combined 2nd-NL and 3rd-NL in CPPLN for broadband white laser generation.
• This approach offers a pathway to high peak power, ultrabroadband vis-NIR white lasers.
• The findings pave the way for potentially achieving full ultraviolet-visible-infrared spectrum lasers.