Beyond Limits: The Amazing Power of Water in Laser Development

Water helps to generate ultra continuous white lasers with an extremely wide wavelength range.
Researchers have made significant progress in creating ultra wideband white laser sources, which have a wide wavelength range from ultraviolet to far-infrared. These advanced lasers are used in various fields, including imaging, femtosecond chemistry, telecommunications, laser spectroscopy, sensing, and ultrafast science.

Intense white laser projects a brilliant rainbow
However, this pursuit faces challenges, especially in selecting suitable nonlinear media. Although traditional solid materials are efficient, they are susceptible to optical damage under peak power conditions. Although gas media have resistance to damage, they are usually inefficient and technically complex.

Innovative solutions using water as a nonlinear medium
Researchers from South China University of Technology have recently taken non-traditional measures to treat water as a nonlinear medium. Water is abundant and inexpensive, and can be protected from optical damage even under the influence of high-power lasers. As reported in the Journal of Advanced Photonics in the Golden Open Access journal, water induced spectral broadening involves enhanced self phase modulation and stimulated Raman scattering, resulting in a supercontinuum white laser with a bandwidth of 435nm and 10dB, covering an impressive range of 478-913nm.

Progress in Cooperation between Water and CPPLN
To further innovate, researchers combined water with chirped periodically polarized lithium niobate (CPPLN) crystals, which are known for their powerful second-order nonlinear power. This cooperative relationship not only expands the frequency range of supercontinuum white laser, but also flattens its output spectrum. According to Professor Zhi Yuan Li, the senior author of the study, "The cascaded water CPPLN module provides a long lifespan, high stability, and low cost technical route for achieving 'three high' white lasers with strong pulse energy, high spectral flatness, and ultra wide bandwidth."

The results of the water CPPLN cooperation are expected. The pulse energy of this ultra wideband ultra continuous spectrum light source is 0.6 mJ, with a 10 dB bandwidth spanning one octave (413-907nm), and it has potential in ultrafast spectroscopy and hyperspectral imaging. Zhi Yuan Li observed, "It provides high resolution of physical, chemical, and biological processes at extreme spectral bandwidths with high signal-to-noise ratio. It opens up an efficient pathway to create long-lived, highly stable, and cost-effective white light lasers with strong pulse energy, high spectral flatness, and ultra wideband, paving the way for new possibilities in scientific research and application."

Source: Sohu