December 2021
Spotlight Summary by Thibaut Sylvestre
Octave-spanning supercontinuum generation from off-axis Raman oscillation in a monolithic KTP crystal
A longstanding challenge since the invention of the laser has been the development of efficient methods to exploit optical nonlinearities to convert laser light to new wavelengths. Supercontinuum (SC) generation in nonlinear materials has been shown to offer a convenient and elegant solution to this challenge, as it massively broadens the laser spectrum while maintaining a spatially coherent output.
Writing in Optics Letters, Ming-Hsiung Wu and collaborators have now implemented a new method based on an off-axis monolithic KTP crystal Raman oscillator, in which waves resonate with zigzag paths via total internal reflections between the crystal surfaces. When pumped with a Q-switched Nd:YAG laser at 1064 nm, the KTP crystal oscillator generates a cascade of Raman Stokes waves with an ultrabroad bandwidth across the near-infrared up to 1800 nm, which is simultaneously down-converted into the visible from 540 nm to 750 nm through second-harmonic generation (SHG) and sum-frequency generation (SFG). Wu et al. further demonstrated two efficient schemes to couple out this supercontinuum light trapped in the monolithic KTP oscillator, using either a linear array fiber bundle or a wedge-polished glass rod to frustrate the total internal reflections. This novel Raman SC comb light source is compact and simple, and therefore could find many applications in spectroscopy and microscopy.
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Writing in Optics Letters, Ming-Hsiung Wu and collaborators have now implemented a new method based on an off-axis monolithic KTP crystal Raman oscillator, in which waves resonate with zigzag paths via total internal reflections between the crystal surfaces. When pumped with a Q-switched Nd:YAG laser at 1064 nm, the KTP crystal oscillator generates a cascade of Raman Stokes waves with an ultrabroad bandwidth across the near-infrared up to 1800 nm, which is simultaneously down-converted into the visible from 540 nm to 750 nm through second-harmonic generation (SHG) and sum-frequency generation (SFG). Wu et al. further demonstrated two efficient schemes to couple out this supercontinuum light trapped in the monolithic KTP oscillator, using either a linear array fiber bundle or a wedge-polished glass rod to frustrate the total internal reflections. This novel Raman SC comb light source is compact and simple, and therefore could find many applications in spectroscopy and microscopy.
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Article Information
Octave-spanning supercontinuum generation from off-axis Raman oscillation in a monolithic KTP crystal
Ming-Hsiung Wu, Yan-Jou Lin, Fredrik Laurell, and Yen-Chieh Huang
Opt. Lett. 46(23) 5990-5993 (2021) View: Abstract | HTML | PDF