Multimodal coherent anti-Stokes Raman spectroscopic imaging with a fiber optical parametric oscillator

Abstract

We report on multimodal coherent anti-Stokes Raman scattering ͑CARS͒ imaging with a source composed of a femtosecond fiber laser and a photonic crystal fiber ͑PCF͒-based optical parametric oscillator ͑FOPO͒. By switching between two PCFs with different zero dispersion wavelengths, a tunable signal beam from the FOPO covering the range from 840 to 930 nm was produced. By combining the femtosecond fiber laser and the FOPO output, simultaneous CARS imaging of a myelin sheath and two-photon excitation fluorescence imaging of a labeled axons in rat spinal cord have been demonstrated at the speed of 20 s per pixel.

Fiber optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy

“…OPOs that accomplish frequency conversion through FWM in PCF have been studied as well and are summarized in [11]. One designed for multimodal CARS imaging uses a femtosecond seed laser [12], resulting in low pulse energy (0.1–0.5 nJ) and low spectral resolution and efficiency.…”

Heterodyne detected nonlinear optical imaging in a lock‐in free manner

“…At the LO power below 1 mW, the TAMP improved the SNR by up to 10 times compared to LIA based detection. Such improvement opens the opportunity for high-speed, high-quality SRS imaging with low power sources such as Er: fiber lasers [20], photonic crystal fiber [21,22] or fiber optical parametric oscillator [23] recently developed as compact and cost-effective alternatives to solid state lasers.…”

Coherent Raman Scattering Microscopy in Biology and Medicine

“…Multimodal nonlinear microscopy has been developed and is based on synchronized lasers (125), single titanium (Ti) sapphire lasers (67), OPO systems (126), and fiber lasers (127, 128). With an appropriate design, various nonlinear optical signals can be collected simultaneously (85).…”

“…Accordingly, fiber-based optical parametric amplifiers, OPOs, soliton-wave converters, and supercontinuum sources have been developed to broaden the spectral coverage, and these have been successfully applied to achieve high-quality CARS microscopy (34, 101, 127, 128, 160–163). However, problems occur when fiber lasers meet SRS imaging.…”