Long-distance axial spectral encoding using space-time wave packets.

Area of Science:

• Optics and Photonics
• Laser Physics
• Wave Phenomena

Background:

• Space-time wave packets (STWPs) are engineered optical beams known for their ability to maintain their shape during propagation.
• Traditional applications focus on propagation invariance, but novel spectral behaviors are possible.

Purpose of the Study:

• To demonstrate and characterize a novel propagation configuration termed axial spectral encoding in space-time wave packets.
• To explore the potential of STWPs for applications in ranging and sensing through spectral measurements.

Main Methods:

• Experimental demonstration of axial spectral encoding using STWPs in an open-field laser range.
• Verification of two distinct spectral encoding configurations: distance-dependent spectral shift and parameter-induced spectral change.

Main Results:

• Achieved stable axial spectral encoding over propagation distances of hundreds of meters.
• Demonstrated on-axis spectral blue-shifting and red-shifting with propagation distance.
• Showcased spectral modification at a fixed axial position by tuning internal STWP parameters.

Conclusions:

• Axial spectral encoding is a viable and robust propagation characteristic of STWPs.
• The demonstrated spectral control opens avenues for advanced LIDAR and remote sensing techniques.
• Spectral measurements of STWPs offer a new paradigm for distance determination and environmental monitoring.