Abstract: Optical sensing techniques and devices based on detection of fluorescent emissions at different optical wavelengths by nonlinear optical absorption of different excitation beams at different excitation wavelengths that interact with fluorescently-labeled structures within the sample to cause nonlinear optical absorption of two or more photons at each excitation wavelength. The fluorescent light at different fluorescent emission wavelengths by nonlinear optical absorption of excitation light at a particular excitation wavelength is spectrally separated into different optical channel output beams along different optical channel optical paths at different designated fluorescent imaging wavelength bands and the fluorescent light at different fluorescent imaging wavelengths within each designated fluorescent imaging wavelength is detected.

Abstract: Optical sensing techniques and devices based on detection of fluorescent emissions at different optical wavelengths by nonlinear optical absorption of different excitation beams at different excitation wavelengths that interact with fluorescently-labeled structures within the sample to cause nonlinear optical absorption of two or more photons at each excitation wavelength. The fluorescent light at different fluorescent emission wavelengths by nonlinear optical absorption of excitation light at a particular excitation wavelength is spectrally separated into different optical channel output beams along different optical channel optical paths at different designated fluorescent imaging wavelength bands and the fluorescent light at different fluorescent imaging wavelengths within each designated fluorescent imaging wavelength is detected.