Waveguide-based optical parametric oscillator for coherent Raman scattering applications

Abstract A waveguide-based optical parametric oscillator for coherent Raman scattering applications is presented, exploiting four-wave mixing in a silicon nitride waveguide. Benefiting from its long propagation length of 20 mm in combination with a narrowband pump laser, idler pulses with an energy of up to 210 pJ and a spectral bandwidth down to 11.2 $$\hbox {cm}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>cm</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> were obtained. By combining these narrowband idler pulses and the residual pump pulses, coherent Raman spectroscopy and microscopy were possible with a signal-to-noise ratio of up to 13.4. Thus, the presented compact and stable waveguide-based light source paves the way towards integrated lab-on-a-chip coherent Raman applications.