Raman fiber laser
Raman finer laser is an technology to build high power laser sources outside emission window of conventional rare earth doped gain media. Emission bands of conventional ytterbium, erbium, and thulium/holmium-doped fiber lasers are limited to specific wavelength bands. Raman laser is based on Raman gain based on stimulated Raman scattering (SRS), which is available at arbitrary wavelength in the entire transparency window of optical fiber.
Cascaded Raman Fiber Laser
Cascaded Raman conversion is a process in which multiple stages of Raman scattering occur in a fiber. In this process, the first Raman stage converts a pump laser into a Stokes beam, which can then serve as the pump for a second Raman stage. This second stage can then produce a new Stokes beam, which can serve as the pump for a third Raman stage, and so on. Each successive Raman stage produces a new Stokes beam with a longer wavelength than the previous stage. This enables the creation of a cascade of Stokes wavelengths, which can cover a broad spectral range.
Video: Cascaded Raman Conversion for an Yb pump.
References:
- Goswami, Abhigyan, Swathi Padmanabhan, Sarthak Dash, Jaya Prakash, and V. R. Supradeepa. “Pulsed cascaded Raman fiber laser widely tunable in the second near-infrared and visible window for hyperspectral photoacoustic imaging.”Ā Optics Letters 50, no. 7 (2025): Ā 2223-2226.Ā https://doi.org/10.1364/OL.553618.
- Goswami, Abhigyan, Swathi Padmanabhan, Sarthak Dash, Jaya Prakash, and V. R. Supradeepa. “Widely tunable Raman fiber laser for hyperspectral photoacoustic imaging.” InĀ Photons Plus Ultrasound: Imaging and Sensing 2025, vol. 13319, pp. 193-197. SPIE, 2025.Ā https://doi.org/10.1117/12.3043020