Widely-tunable synchronisation-free picosecond laser source for multimodal CARS, SHG, and two-photon microscopy
Abstract
We demonstrate a continuous wave (CW) seeded synchronization-free optical parametric amplifier (OPA) pumped by a picosecond, 1 µm laser and show its performance when used as a simple yet powerful source for label-free coherent anti-Stokes Raman scattering (CARS), concurrent second harmonic generation (SHG), and two-photon fluorescence microscopy in an epi-detection geometry. The average power level of above 175 mW, spectral resolution of 8 cm−1, and 2 ps pulse duration are well optimized for CARS microscopy in bio-science and bio-medical imaging systems. Our OPA is a much simpler setup than either the “gold-standard” laser and optical parametric oscillator (OPO) combination traditionally used for CARS imaging, or the more recently developed OPA systems pumped with femtosecond pulses [1]. Rapid and accurate tuning between resonances was achieved by changing the poled channels and temperature of the periodically-poled lithium niobate (PPLN) OPA crystal together with the OPA seed wavelength. The Pump-Stokes frequency detuning range fully covered the C-H stretching band used for the imaging of lipids. By enabling three multiphoton techniques using a compact, synchronization free laser source, our work paves the way for the translation of label-free multi-photon microscopy imaging from biomedical research to an imaging based diagnostic tool for use in the healthcare arena.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 26, 2021
- Source ID
- 10.1364/boe.411620
Entities
People
- David J. Richardson
- Duanyang Xu
- James Read
- Jonathan H. V. Price
- Konstantinos N. Bourdakos
- Lin Xu
- Peter Johnson
- Sijing Liang
- Sumeet Mahajan
Organizations
- Air Force Office of Scientific Research
- Engineering and Physical Sciences Research Council
- European Research Council