Resonant second-harmonic-generation circular-dichroism microscopy   reveals molecular chirality in native biological tissues
  Conventional linear optical activity effects are widely used for studying chiral materials. However, poor contrast and artifacts due to sample anisotropy limit the applicability of these methods. Here we demonstrate that nonlinear second-harmonic-generation circular dichroism spectral microscopy can overcome these limits. In intact collagenous tissues, clear spectral resonance is observed with sub-micrometer spatial resolution. By performing gradual protein denaturation studies, we show that the resonant responses are dominantly due to the molecular chirality. 
Mei-Yu Chen, Mikko J. Huttunen, Che-Wei Kan, Yen-Yin Lin, Cin-Wei Ye,   Meng-Jer Wu, Hsiang-Lin Liu and Shi-Wei Chu
physics.bio-ph physics.optics