Label-free identification of tumor tissues by coherent nonlinear vibrational mode imaging

A multimodal hyperspectral VSFG microscope platform, comprising:

• a pulsed laser beam;
• an optical parametric amplifier (OPA), configured to guide the output of the laser beam, generating a mid-infrared (MIR) beam;
• a Fabri-Perot etalon, configured to pass the residue laser beam from the OPA for an up-conversion near IR (NIR) beam;
• a dichroic mirror (DM), wherein the MIR beam and the NIR beam are spatially overlapped;
• a resonant beam scanner mounted to an integrated 2-position slider (I2PS);
• an inverted microscope configured to integrate with the beam scanner, wherein the MIR beam and the NIR beam are overlapped and are directed into the inverted microscope;
• a reflective-based infinity-corrected Schwarzschild objective (SO) and a refractive-based infinity-corrected imaging objective (RO) mounted to a vertical nanopositioning (VNP) z-axis stage;
• a microscope stage for retaining a sample, mounted between the SO and the RO, whereby overlapped beams from SO are focused onto the sample and a VSFG signal generated by the sample is collected by RO;
• a linear polarizer and a telecentric tube lens system, whereby the signal is guided through and processed;
• a monochromator (MC), wherein a magnified image formed at the entrance slit of the MC;
• and
• a charge-coupled device (CCD) coupled with the linear polarizer and the telecentric tube lens system, whereby a magnified image and data are detected and collected.